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Car Forum / Driving, Maintenance, Tuning / Driving / July 2008suicyclists again
jeez... these idiots really are trying to kill themselves. Leaving Metro station, I come to a four way stop in a residential neighborhood. I stop, look left, right, left, proceed. I'm just entering the intersection when this idiot roadie, who was apparently hugging the curb on the street crossing mine, blows the sign at about 15 MPH and has the audacity to give me a "whaaaat? whaaaa'd I do?" look as I screech to a stop and lay on the horn. f.cking retards. No reason for this whatsoever, he was too busy chatting with his buddy who peeled off to the right at the intersection (also blowing the sign.) No way I could have reasonably seen either one (or they me, for that matter, unless they had slowed to a near-stop; there's a REASON there's a stop sign there) there was a tall hedge right up against the sidewalk. Goddamn, some people are just too stupid to live. My only "consolation" is that one of these pricks will end up on the ground someday, but I have no doubt that they'll keep blaming "cagers" for their misfortunes, and likely some motorist will wrongfully accept legal blame for the incident. nate  Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel > jeez... these idiots really are trying to kill themselves. Leaving > Metro station, I come to a four way stop in a residential neighborhood. [quoted text clipped - 12 lines] > doubt that they'll keep blaming "cagers" for their misfortunes, and > likely some motorist will wrongfully accept legal blame for the incident. Between saturday and sunday I rode 60 miles. On sunday on my way home I am approaching a red signal in the right lane. I am doing it at speed which would be acceptable while driving. This woman driving a minivan zooms up on my left and then changes lanes into the right lane (intending to turn right) to stop in front of me I have to take evasive action for her. Since this is towards the end of 60 miles of riding I am getting a little tired of such asshattery. I pass her back saying 'two can play this game' as I pass her open window. I stop in my proper place in the queue where upon she goes into some tirade about how bicyclists don't belong on the road. I even rode some glorified sidewalk when I didn't feel up to keeping up a sprint for miles on a two lane road. It sucked more than I remember it sucking. potholed worse than the road, ducking tree limbs, blind driveways... arg. >> jeez... these idiots really are trying to kill themselves. >> Leaving Metro station, I come to a four way stop in a [quoted text clipped - 23 lines] > into the right lane (intending to turn right) to stop in front > of me I have to take evasive action for her. Why did you have to take evasive action? Shouldn't you have been slowing down for the red light that you were approaching? >>>jeez... these idiots really are trying to kill themselves. >>>Leaving Metro station, I come to a four way stop in a [quoted text clipped - 26 lines] > Why did you have to take evasive action? Shouldn't you have been > slowing down for the red light that you were approaching? I'm envisioning that she in effect did a swoop and squat on Brent, albeit not necessarily with malice. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >>>>jeez... these idiots really are trying to kill themselves. >>>>Leaving Metro station, I come to a four way stop in a [quoted text clipped - 31 lines] > > nate evidently,the bike's speed was -not- "acceptable" to the driver... SignatureJim Yanik jyanik at kua.net > evidently,the bike's speed was -not- "acceptable" to the driver... Yanik, it's the 'must pass bicycle' mentality of people like you. They aren't rational. I've approached that light at the same speed driving and nobody ever pulled that sort of move on me. I often ride 25mph on 25mph residential streets. Drivers will do anything (including kicking it up to about 40mph) they can to pass me. I drive 25mph on the same streets and not one driver has *EVER* passed me. There is a whole host of sh.t people will do when you're biking that they don't even think of doing if you are driving. > evidently,the bike's speed was -not- "acceptable" to the driver... Bingo. If a driver is capable of doing a "swoop and squat" with more than 3 feet of clearance in front of a biker, he's entitled to. >> evidently,the bike's speed was -not- "acceptable" to the driver... > > Bingo. If a driver is capable of doing a "swoop and squat" with more > than 3 feet of clearance in front of a biker, he's entitled to. If you hurt someone doing that galt I hope you're charged at least as severely as that doctor. >> evidently,the bike's speed was -not- "acceptable" to the driver... > > Bingo. If a driver is capable of doing a "swoop and squat" with more > than 3 feet of clearance in front of a biker, he's entitled to. Wow, I'm glad you guys don't live around here. Oh, wait, you just might. Drivers here seem just as assaholic as you. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >>> evidently,the bike's speed was -not- "acceptable" to the driver... >> [quoted text clipped - 4 lines] > > Oh, wait, you just might. Drivers here seem just as assaholic as you. I just had a woman in an SUV do that galt stunt on me maybe 10 minutes ago. Her windows were open so I pulled up next to the driver's side tail lamp and started talking to her and about how she had acted. She put her fingers over her left ear and just looked forward. Sick people. They really think that sort of behavior is acceptable and that other people are less than weeds to them. I should have given the 1/4 panel of her suv a good non-damaging thwap to see if she could have heard that.... They value their vehicles enough that might be the only way to get them to start behaving properly. >>> evidently,the bike's speed was -not- "acceptable" to the driver... >> [quoted text clipped - 6 lines] > > nate doesn't it seem to you that Brent P has a LOT of problems while biking? after reading many of his posts,I get that impression. Also seems that he's aggressive. SignatureJim Yanik jyanik at kua.net >>>>evidently,the bike's speed was -not- "acceptable" to the driver... >>> [quoted text clipped - 10 lines] > after reading many of his posts,I get that impression. > Also seems that he's aggressive. You just advocated very aggressive driving, so I really don't care what your opinion of Brent may be. I too am constantly annoyed while driving, mostly because neither drivers nor cyclists seem to give a f.ck about legality or safety. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >>>>>evidently,the bike's speed was -not- "acceptable" to the driver... >>>> [quoted text clipped - 12 lines] > > You just advocated very aggressive driving, No,I did not;I disputed Brent's description of the situation. I'm saying his nature -seems- to take offense at a lot of things,and I wonder about the true situation. > so I really don't care what > your opinion of Brent may be. Well,that says a lot right there..... I guess there's no need to take this any further,your mind is made up. Adios. > I too am constantly annoyed while driving, mostly because neither > drivers nor cyclists seem to give a f.ck about legality or safety. > > nate SignatureJim Yanik jyanik at kua.net > No,I did not;I disputed Brent's description of the situation. > I'm saying his nature -seems- to take offense at a lot of things,and I > wonder about the true situation. I think you need to look up "aggressive" then. And as far as 'taking offense', gee Jim, how about you have someone ignore that there is a left lane and decide to brush pass you just because the don't like bicyclists.... how about you get cut off and then have someone nail the brakes... see if you 'take offense'. Do I take offense when someone decides to risk my life so they can wait at red signal a little longer? Sure, that's pretty natural I think. Look at all the things that have been criminalized that are drivers puting a cop's life at risk. Cops seem to 'take offense' to having someone brush past them at 50mph. >>>>>>evidently,the bike's speed was -not- "acceptable" to the driver... >>>>> [quoted text clipped - 16 lines] > I'm saying his nature -seems- to take offense at a lot of things,and I > wonder about the true situation. You'd be offended too if someone cut you off with three feet to spare and nailed the brakes. >>so I really don't care what >>your opinion of Brent may be. > > Well,that says a lot right there..... > I guess there's no need to take this any further,your mind is made up. > Adios. If you truly believe that three feet is enough clearance to give another road user, your opinion is meaningless. nate >>I too am constantly annoyed while driving, mostly because neither >>drivers nor cyclists seem to give a f.ck about legality or safety. >> >>nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >>>> evidently,the bike's speed was -not- "acceptable" to the driver... >>> [quoted text clipped - 8 lines] > > doesn't it seem to you that Brent P has a LOT of problems while biking? Not for where I do it and the milage I do. I've worked with guys who rode a lot and when they rode the same roads I did they had problems. > after reading many of his posts,I get that impression. Because I never talk about all the miles I do that have no event to speak of duh. This thread branch was about one above average idiot I encountered in 60 miles of biking. ONE in SIXTY miles. > Also seems that he's aggressive. I'm riding along minding my own business when someone decides to brush pass me, swoop and squat, or whatever hostile or ignorant act they decide on and I'm the 'aggressive' one? I think you're using the gpstroll dictionary. >>> jeez... these idiots really are trying to kill themselves. >>> Leaving Metro station, I come to a four way stop in a [quoted text clipped - 26 lines] > Why did you have to take evasive action? Shouldn't you have been > slowing down for the red light that you were approaching? I am still wondering if you're a troll or just very stupid. She cuts me off and nails the brakes. She just shortened my stopping space by the length of her minivan and the space in front of her to the next vehicle. My rate of slowing was set to use most of that space. DUH! >>> Between saturday and sunday I rode 60 miles. On sunday on my >>> way home I am approaching a red signal in the right lane. I am [quoted text clipped - 11 lines] > to the next vehicle. My rate of slowing was set to use most of > that space. DUH! Nah, I'm neither Brent, regardless of your childish name calling. >>>> Between saturday and sunday I rode 60 miles. On sunday on my >>>> way home I am approaching a red signal in the right lane. I am [quoted text clipped - 13 lines] > > Nah, I'm neither Brent, regardless of your childish name calling. unless you're on a sandy,dirty,oily,or icy road,bikes can stop in very short distances. Without tossing yourself over the handlebars.... SignatureJim Yanik jyanik at kua.net > unless you're on a sandy,dirty,oily,or icy road,bikes can stop in very > short distances. Without tossing yourself over the handlebars.... Um... bicycles take longer to stop than most cars from the same speed. Basic physics of contact patch and swept braking area are in play. A road bicycle has very little of each. On Jul 9, 12:23 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > unless you're on a sandy,dirty,oily,or icy road,bikes can stop in very > > short distances. Without tossing yourself over the handlebars.... > > Um... bicycles take longer to stop than most cars from the same > speed. Gotta cite...? > Basic physics of contact patch and swept braking area are in > play. A road bicycle has very little of each. Have you ever considered just having your mommy drive you to the bus station? I have a strong suspicion you couldn't walk there on your own without experiencing your usual trials and tribulations. ----- - gpsman On Jul 9, 12:23 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > unless you're on a sandy,dirty,oily,or icy road,bikes can stop in very > > short distances. Without tossing yourself over the handlebars.... > > Um... bicycles take longer to stop than most cars from the same > speed. Do you really think so? I can stop my bikes pretty darn quick. In approximately one bike length if I don't mind tumbling over the handlebars, but even without the tumble I can stop very shortly. All the weight back, but over the rear tire, and grab the front brakes. Pull until rear wheel is airborne and approaching flipover point, modulate as necessary. How long do you figure it takes the average car to stop from 25mph? I'd bet I could stop shorter on a bicycle. Very high performance cars may give me a run for my money. > Basic physics of contact patch and swept braking area are in > play. A road bicycle has very little of each. You forgot mass you're bringing to a stop. Since the bicycle also has very little mass in motion, it needs much less of a contact patch. >On Jul 9, 12:23 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> >wrote: [quoted text clipped - 13 lines] >car to stop from 25mph? I'd bet I could stop shorter on a bicycle. >Very high performance cars may give me a run for my money. A car with 1g coefficient of friction between its tires and asphalt can stop from 25mph in about 21 feet. A bicycle with 1g coefficient of friction between its tires and asphalt cannot, because the rider will be thrown from the bike before he stops. That is why a bicycle takes longer than a car to stop. >> Basic physics of contact patch and swept braking area are in >> play. A road bicycle has very little of each. > >You forgot mass you're bringing to a stop. Since the bicycle also has >very little mass in motion, it needs much less of a contact patch. At low speed, to first order, mass is not a factor. Nor is the contact patch or the swept braking area; they come into play for a higher-speed stop however, or for braking multiple times in succession. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. On Jul 9, 4:28 pm, russo...@grace.speakeasy.net (Matthew T. Russotto) wrote: > In article <c157c134-8158-44f7-9fd5-dc462835b...@t54g2000hsg.googlegroups.com>, > [quoted text clipped - 37 lines] > > - Show quoted text - From Edmunds I found the following stopping distances from 30MPH: 2008 Civic Si: 32.9 Feet 2008 VW GTI: 32.3 Feet http://tinyurl.com/6ffffw I looked at quite a few vehicles, all 2008 models, and all were over 30 feet, most between 32 & 35. I assume older cars require even more distance to stop, so it’s still not the “most cars” you referenced. I’d guess the stopping distance to be much higher if you took a sampling of the first 30 cars to drive by on an average road. Still, I’d bet I can beat 30 feet from 30MPH on my pedal bike, which would be better than _any_ of the cars. If I can find the time tonight I’ll check it out and see just how quick I can stop my bike. Where did you get the 21’ from 25MPH? What type of tire and road conditions have a 1g coeffecient? Brents claim was for an average car, I would be less surprised to hear that a supercar could outbrake my bicycle than your average 10 year old sedan. > 2008 Civic Si: 32.9 Feet > 2008 VW GTI: 32.3 Feet [quoted text clipped - 8 lines] > better than _any_ of the cars. If I can find the time tonight I?ll > check it out and see just how quick I can stop my bike. I bet you can't without falling. Especially when going down hill. This past weekend I rode a rather decently steep downhill. I knew there was a stop sign at T-intersection below where I had to turn right. I was on the brakes the whole way down so I could make that stop. > Where did you get the 21? from 25MPH? What type of tire and road > conditions have a 1g coeffecient? Brents claim was for an average > car, I would be less surprised to hear that a supercar could outbrake > my bicycle than your average 10 year old sedan. Brakes haven't changed that much in the last 15 years. And if you discount ABS we're talking around 30. Bicycles can change direction fast. They do not stop very fast from automotive type speeds. Biking 15mph is not the same as biking 30mph or more. There's the one downhill where the light at the bottom changed on me a little earlier than I thought. I could have stopped my car in the space remaining... I stopped well into the intersection on the bike. I had even locked the rear wheel briefly and took the tread layer in a section of the almost new tire. Any attempt at faster braking would have put me on the pavement. Maybe I'll pace out a 25mph stop later. I don't think I have 30mph in me today... nor the space to reach it without dealing with traffic. > > 2008 Civic Si: 32.9 Feet > > 2008 VW GTI: 32.3 Feet [quoted text clipped - 10 lines] > > I bet you can't without falling. Especially when going down hill. I planned to test this theory tonight, but we got serious thundershowers on my ride home. My bike, the roads and myself are all wet. Maybe I'll give it a whirl tomorrow. I'm not saying I know I can, just that I suspect I can. What's the bet? I may take it. > This > past weekend I rode a rather decently steep downhill. I knew there was a > stop sign at T-intersection below where I had to turn right. I was on > the brakes the whole way down so I could make that stop. Again, I'd like a more detailed description of "on the brakes" in your riding. Not to be argumentative, I could very well be wrong about all this, but just in the interest of having the details. For me, if I'm in an all-out brake, the rear wheel will leave the ground for at least part of my speeds descent. > > Where did you get the 21? from 25MPH? What type of tire and road > > conditions have a 1g coeffecient? Brents claim was for an average [quoted text clipped - 3 lines] > Brakes haven't changed that much in the last 15 years. And if you > discount ABS we're talking around 30. I agree. I'd say the average car has moderate, but not great tires and ABS. I'd be willing to put odds I could outstop my pickup, but it's not an average car, and has a stopping distance of more than what I'd consider an average car. I just want to make sure we're talking about the same average - not an 08 showroom car with great condition extra-wide tires, and not my beat up old truck. > Bicycles can change direction fast. They do not stop very fast from > automotive type speeds. Biking 15mph is not the same as biking 30mph or [quoted text clipped - 6 lines] > of the almost new tire. Any attempt at faster braking would have put me > on the pavement. The fact that you skidded your rear tire enough to take tread off of it suggest to me you were not stopping as shortly as you could have been. > Maybe I'll pace out a 25mph stop later. I don't think I have 30mph in me > today... nor the space to reach it without dealing with traffic. I'd be very curious with your results (even more curious if you measured rather than paced the distance). I'll be able to produce mine next dry afternoon, hopefully tomorrow. I'll have a spotter or two to make sure I am braking right at the mark, and I'll make a few runs for consistency. I'll leave a marker at each stop point and measure with my 30' tape. It'll have to be the mountain bike as it's the only one with gears to get me to 30MPH. I'd actually be more comfortable doing it from 25 but couldn't find 25-0 specs on any cars. >> > 2008 Civic Si: =A032.9 Feet >> > 2008 VW GTI: =A032.3 Feet [quoted text clipped - 15 lines] >wet. Maybe I'll give it a whirl tomorrow. I'm not saying I know I >can, just that I suspect I can. What's the bet? I may take it. That you can't stop within 30 feet from 30mph on a bicycle on flat ground, without injuring yourself? I'd be in for $100, but I'd want independent verification of course. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. On Jul 10, 4:04 pm, russo...@grace.speakeasy.net (Matthew T. Russotto) wrote: > In article <7f70e54a-4707-4090-84de-308028cfd...@y38g2000hsy.googlegroups.com>, > [quoted text clipped - 28 lines] > > - Show quoted text - I won't bet $100, since I'm not in the position to lose it and I'm not that sure. Like I said, I think I can, I'm not sure. The initial deal was is a bicycle capable of stopping as fast as an average car from 30MPH. The brand new cars I found on Edmunds were mostly 33-35 feet from 30MPH. That leads me to believe average car (most cars have worn tires, many are older, not all brakes are brand new, etc) is more like 35-38, but I'll stick with 33-35. Call it 33, there's no way to claim an "average car" can stop faster than that from 30MPH, agreed? My intention was a "fun bet", a $10 Starbucks gift card or something. Your willingness to bet a c-note combined with your fondness for physics certainly has me doubting myself, but I still think I can do it (although with less fervor than before). Also, you mentioned road bike. I am planning to execute my test on a mountain bike, since it's the only one I have with gears, and as such the only one I have that can reach 30MPH. Does this change your opinion of my test, or make it seem more likely? The extra tire shouldn't matter since I won't be skidding the front wheel regardless, it's simply a matter of how much brake can I apply without going over the bars and how fast will that stop me. Also, I'm not sure what you'd want for independent verification, unless you have any friends on the seacoast by the NH/MA border that would like to swing by tonight. I could have someone record it on my digital camera, but am not sure how the resolution will pan out. Even if the general action plays out, there'd be no way to show my speedo and the tape measure I'll be stopping alongside. I guess we’ll have to settle for a gentlemen’s bet, with my word I’ll be honest and you reserving the right to call bullshit on my stopping distances if you so choose. >I won't bet $100, since I'm not in the position to lose it and I'm not >that sure. Like I said, I think I can, I'm not sure. Smart move. >The initial >deal was is a bicycle capable of stopping as fast as an average car [quoted text clipped - 3 lines] >like 35-38, but I'll stick with 33-35. Call it 33, there's no way to >claim an "average car" can stop faster than that from 30MPH, agreed? Sure. I think it's still impossible to stop a bike faster than that too. But I wouldn't be as willing to risk the C-note as for the sheer impossibility of 30 feet. >it (although with less fervor than before). Also, you mentioned road >bike. I am planning to execute my test on a mountain bike, since it's [quoted text clipped - 4 lines] >brake can I apply without going over the bars and how fast will that >stop me. A mountain bike with knobbies on pavement should be worse than a road bike on pavement. With slicks, no big difference. >and the tape measure I'll be stopping alongside. I guess we=92ll have >to settle for a gentlemen=92s bet, with my word I=92ll be honest and you >reserving the right to call bullshit on my stopping distances if you >so choose. I think you'll be surprised. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. On Jul 10, 5:19 pm, russo...@grace.speakeasy.net (Matthew T. Russotto) wrote: > In article <1493ccb8-1ead-4dde-8d4d-eb3c56820...@p25g2000hsf.googlegroups.com>, > [quoted text clipped - 4 lines] > > Smart move. Fair enough. > >The initial > >deal was is a bicycle capable of stopping as fast as an average car [quoted text clipped - 7 lines] > too. But I wouldn't be as willing to risk the C-note as for the sheer > impossibility of 30 feet. What's your guess on the stopping distance? It does have knobbies, by the way. I still think the limiting factor will be not flipping as opposoed to traction, so I don't think it'll make much of a difference. > >it (although with less fervor than before). Also, you mentioned road > >bike. I am planning to execute my test on a mountain bike, since it's [quoted text clipped - 7 lines] > A mountain bike with knobbies on pavement should be worse than a road bike on > pavement. With slicks, no big difference. I'll be on knobbies. I don't forsee skidding the front, so I don't expect much of a difference. > >and the tape measure I'll be stopping alongside. I guess we=92ll have > >to settle for a gentlemen=92s bet, with my word I=92ll be honest and you > >reserving the right to call bullshit on my stopping distances if you > >so choose. > > I think you'll be surprised. I very well may be. That's the fun of experimentation. >What's your guess on the stopping distance? It does have knobbies, by >the way. I still think the limiting factor will be not flipping as >opposoed to traction, so I don't think it'll make much of a >difference. I'll say 38'. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. >On Jul 9, 4:28pm, russo...@grace.speakeasy.net (Matthew T. Russotto) >wrote: [quoted text clipped - 50 lines] >Id bet I can beat 30 feet from 30MPH on my pedal bike, which would be >better than _any_ of the cars. I'd bet you can't. You'd need a coefficient of friction slightly GREATER than 1, and you'd need not to flip over. >Where did you get the 21 from 25MPH? What type of tire and road >conditions have a 1g coeffecient? Brents claim was for an average >car, I would be less surprised to hear that a supercar could outbrake >my bicycle than your average 10 year old sedan. The 21 feet is a theoretical minimum for a tire with coefficient of friction of 1. This is actually a pretty reasonable number for a performance car tire; there are a few tires with Cf > 1. I doubt road bike tires have a Cf that high; you simply don't need tires that sticky on a bike, because of the limited torque available. Minimum stopping distance is given by the formula (v^2) / (2 * Cf * g), where v is velocity and g is acceleration due to gravity. Notice that mass is not a factor, nor is swept braking area, nor is contact patch size. When you get into stops from higher speeds, you have to consider that the energy has to go somewhere. But for a single stop from 25mph, it's not a big issue. Notice also that this formula applies to bikes and cars equally -- until you reach the point at which the bike flips over. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. On Jul 10, 3:54 pm, russo...@grace.speakeasy.net (Matthew T. Russotto) wrote: > In article <187d1e8a-eb60-40e0-97d8-343ea89c9...@25g2000hsx.googlegroups.com>, > [quoted text clipped - 83 lines] > > - Show quoted text - Quite a thorough and well thought out response. Makes sense to me, so perhaps I was mistaken in my thougth I can reel it in that quick. We'll find out tonight. If nothing else I learned something today, so I'm already ahead of the game (unless someone takes me for that coffee card bet). > Do you really think so? I can stop my bikes pretty darn quick. In > approximately one bike length if I don't mind tumbling over the [quoted text clipped - 4 lines] > car to stop from 25mph? I'd bet I could stop shorter on a bicycle. > Very high performance cars may give me a run for my money. Sorry, not from 30+mph on a downhill you aren't. Or 30mph period. I am not talking normal car braking vs. full out bicycle braking. I am talking full decel possible of both from the same speed. Remember, I ride and drive. I know full well the limitations of the bicycle brakes. >> Basic physics of contact patch and swept braking area are in >> play. A road bicycle has very little of each. > You forgot mass you're bringing to a stop. Since the bicycle also has > very little mass in motion, it needs much less of a contact patch. I didn't forget it. I live it. > > Do you really think so? I can stop my bikes pretty darn quick. In > > approximately one bike length if I don't mind tumbling over the [quoted text clipped - 8 lines] > not talking normal car braking vs. full out bicycle braking. I am > talking full decel possible of both from the same speed. I agree. I'm sure the edmunds distances are max stopping in deal conditions. I am thining of the same on my bike. > Remember, I ride and drive. I know. That's one of the reasons I responded to you. > I know full well the limitations of the > bicycle brakes. If you wouldn't mind, describe your max braking technique for your bike. How much of the lever(s) you pull in, which levers, body position, does the rear wheel unweight or lift? > >> Basic physics of contact patch and swept braking area are in > >> play. A road bicycle has very little of each. > > You forgot mass you're bringing to a stop. Since the bicycle also has > > very little mass in motion, it needs much less of a contact patch. > > I didn't forget it. I live it. > > Do you really think so? I can stop my bikes pretty darn quick. In > > approximately one bike length if I don't mind tumbling over the [quoted text clipped - 8 lines] > not talking normal car braking vs. full out bicycle braking. I am > talking full decel possible of both from the same speed. Yeah, and he's telling you you don't know what the f.ck you're talking about, as usual. > Remember, I ride and drive. I know full well the limitations of the > bicycle brakes. Except you don't know those limitations are yours. > >> Basic physics of contact patch and swept braking area are in > >> play. A road bicycle has very little of each. > > You forgot mass you're bringing to a stop. Since the bicycle also has > > very little mass in motion, it needs much less of a contact patch. > > I didn't forget it. I live it. I can't wait to hear your problems riding escalators. ----- - gpsman >>>Do you really think so? I can stop my bikes pretty darn quick. In >>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 29 lines] > > - gpsman Brent's right. You can only brake hard enough for the rear wheel to lift off the ground (assuming that your front brake is strong enough.) Any harder, and you're going for a very unpleasant ride. Cars don't generally have this problem with their much longer wheelbase. In wet/slick conditions it's even worse, as if you slide the front wheel, you're falling down. Oh, wait, it's you. I forgot, you've built your whole Usenet persona about being as wrong as possible on about everything you post. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel > >>>Do you really think so? I can stop my bikes pretty darn quick. In > >>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 33 lines] > lift off the ground (assuming that your front brake is strong enough.) > Any harder, and you're going for a very unpleasant ride. The braking we are talking about is threshhold. For bikes that's "don't flip over the bars", and for cars it's traction. I make a point of stopping VERY short all the time when I ride, and think 30ish feet from 30MPH sounds reasonable. Since the bike I usually do this with doesn't normally have a speedo, and our roads don't have 10' incremental markers on them, I'll have to experiment to see how close my perception is to reality. Anyone want to guess how long I need to stop from 30MPH? > Cars don't generally have this problem with their much longer wheelbase. In > wet/slick conditions it's even worse, as if you slide the front wheel, > you're falling down. I agree. However, the data from Edmunds we're up against was done on a track, in what I'd consider optimal conditions. I won't worry so much about optimal conditions on the bike since traction won't be my limiting factor, but I still won't be doing it on wet roads. I wouldn't begin to make the argument bikes can stop as well on wet/ slick roads as cars can on a track or skidpad. > Oh, wait, it's you. I forgot, you've built your whole Usenet persona > about being as wrong as possible on about everything you post. [quoted text clipped - 5 lines] > > - Show quoted text - >>>>Do you really think so? I can stop my bikes pretty darn quick. In >>>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 36 lines] > wet/slick conditions it's even worse, as if you slide the front wheel, > you're falling down. in wet/slick conditions,one gives themselves more braking distance. if your bike has such lousy braking characteristics,then you have no business GOING 30mph,or even being on a public road. It certainly is not 'cricket' to blame others for that shortcoming of your choice of vehicle. it's called "going too fast for conditions";the conditions being your equipment. > Oh, wait, it's you. I forgot, you've built your whole Usenet persona > about being as wrong as possible on about everything you post. > > nate I doubt Brent was actually going "30MPH" when that woman moved in front of him and braked. SignatureJim Yanik jyanik at kua.net > >>>>Do you really think so? I can stop my bikes pretty darn quick. In > >>>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 59 lines] > > - Show quoted text - Anyone else care to join us in this threshhold braking experiment? My numbers will either prove my claim or show that I was mistaken, but it would be nice to have other peoples data as well. >>>>>>Do you really think so? I can stop my bikes pretty darn quick. In >>>>>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 63 lines] > numbers will either prove my claim or show that I was mistaken, but it > would be nice to have other peoples data as well. You'll have to wait until DC de-swampifies itself. This time of year, even *thinking* about going for a ride makes this transplanted damnyankee all sweaty and smelly. Heck, walking out to my car at 7:30 AM makes me all sweaty. Air conditioning is a wonderful invention. nate (still thinks Philthydelphia would have made a much better capital city...) Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >(still thinks Philthydelphia would have made a much better capital city...) Heck, no, we don't want them up here. Unless you put them across the river in Camden. And take away their bodyguards and cars. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. >>(still thinks Philthydelphia would have made a much better capital city...) > > Heck, no, we don't want them up here. Unless you put them across the > river in Camden. And take away their bodyguards and cars. They'll eventually move to Colorado Springs or some other secure military area in the middle of the country. > Anyone else care to join us in this threshhold braking experiment? My > numbers will either prove my claim or show that I was mistaken, but it > would be nice to have other peoples data as well. Ok... I couldn't find a spot where I could get up to 30, do a full decel stop and then spend time measuring... so I did 25mph on residential roads. I did 4 runs. The first run I braked hard and kept the rear on the edge of lock. 36 of my size 13s. On the second run a woman in an SUV pulled out in front of me and stopped in my path with a deer in the headlights look. Needless to say I aborted. 3rd run the rear wheel locked and lifted I eased back and then found the threshold. 46 of my size 13s. Third run was really from 26mph and change. Again I locked the rear wheel but I think I kept it from actually lifting. 52 of my size 13s. So... this converts to 39 ft, 49.8 ft, and 56.3 ft respectfully. >> Anyone else care to join us in this threshhold braking experiment? My >> numbers will either prove my claim or show that I was mistaken, but it [quoted text clipped - 9 lines] > to say I aborted. 3rd run the rear wheel locked and lifted I eased back > and then found the threshold. 46 of my size 13s. FOURTH run was really correction in caps. > from 26mph and change. Again I locked the rear wheel but I think I kept > it from actually lifting. 52 of my size 13s. > > So... this converts to 39 ft, 49.8 ft, and 56.3 ft respectfully. >>>>>Do you really think so? I can stop my bikes pretty darn quick. In >>>>>approximately one bike length if I don't mind tumbling over the [quoted text clipped - 40 lines] > if your bike has such lousy braking characteristics,then you have no > business GOING 30mph,or even being on a public road. Who said it's "lousy?" The assertion was that it may not be as good as a car, which is a true statement. That doesn't mean that it's unacceptable. > It certainly is not 'cricket' to blame others for that shortcoming of your > choice of vehicle. it's called "going too fast for conditions";the > conditions being your equipment. You mean being cut off? (the situation that Brent described.) Please tell me, what is a safe speed to be cut off at, and how will I know when I'm about to be cut off? >>Oh, wait, it's you. I forgot, you've built your whole Usenet persona >>about being as wrong as possible on about everything you post. [quoted text clipped - 4 lines] > I doubt Brent was actually going "30MPH" when that woman moved in front of > him and braked. It's possible. It's certainly not hard to maintain 20+ on flat ground. Yours Truly can even do that, and I'm a little on the large side for a cyclist. nate Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel > in wet/slick conditions,one gives themselves more braking distance. > if your bike has such lousy braking characteristics,then you have no > business GOING 30mph,or even being on a public road. > It certainly is not 'cricket' to blame others for that shortcoming of your > choice of vehicle. it's called "going too fast for conditions";the > conditions being your equipment. With a bicycle you can change directions easily. This is what you use in emergencies. You don't panic brake like some idiot driving a car. You do that you're gonna meet the pavement. > I doubt Brent was actually going "30MPH" when that woman moved in front of > him and braked. I was going about 17mph. Perfectly acceptable when you have two and half car lengths of space remaining in front of you. I certainly wouldn't have been driving faster in the same location and nobody has ever pulled that move on me when I've been driving. Only when biking. >> Remember, I ride and drive. I know full well the limitations of the >> bicycle brakes. > >Except you don't know those limitations are yours. Do the physics, GPSTroll. SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. >> > unless you're on a sandy,dirty,oily,or icy road,bikes can >> > stop in very short distances. Without tossing yourself over [quoted text clipped - 7 lines] > the handlebars, but even without the tumble I can stop very > shortly. Bicycle stopping distance calc: http://www.exploratorium.edu/cycling/brakes2.html 25mph in 23ft using the default values. Average car stop about 100-130 feet. A Vette can probably stop in 40 feet. I suspect Brent real problem is that he was going to blow through the red light like I see most bicyclists do, and is pissed a vehicle caused him to stop. > Bicycle stopping distance calc: > http://www.exploratorium.edu/cycling/brakes2.html > > 25mph in 23ft using the default values. > Average car stop about 100-130 feet. A Vette can probably stop in 40 > feet. Not this crap again. First you're taking the ABSOLUTE MINIMUM POSSIBLE FOR A BICYCLE WITH DISC BRAKES. A typical bicycle doesn't have disc brakes. Second for a car, you are using absurd Carl Talyor 'speed kills' numbers which include the reaction time of a dead cat and the braking power of a model T ford on Excursion. > I suspect Brent real problem is that he was going to blow through the > red light like I see most bicyclists do, and is pissed a vehicle > caused him to stop. I think you're a stupid troll in the mold of gpstroll, Larry. First, you have the piss-poor memory and reading comprehension ( as I stated before there was already a vehicle stopped in the right lane at the light). Second you assign me assinine qualities (blowing red signals) that I have stated many times I don't do. Thirdly, you act stupid not being able to figure out the most simple of concepts and need them explained to you. This includes tired topics in this newsgroup you should know by now. And fourth, you're getting the same obessive need to reply to my posts where ever you think you see a crack to exploit or a troll to make. On Jul 10, 1:45 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > Bicycle stopping distance calc: > >http://www.exploratorium.edu/cycling/brakes2.html [quoted text clipped - 6 lines] > FOR A BICYCLE WITH DISC BRAKES. A typical bicycle doesn't have disc > brakes. I thought we were talking about absolute minimum stopping distances for all vehicles in question, including bikes? Disc brakes are not really relevant as most rim brakes have more than enough stopping power to lock the front wheel at speed. Discs become an advantage in wet conditions, which is not what we are talking about here. Anyway, the bike I plan to perform my tests on has rim brakes. I'm very confident I will stop far shorter than you did, and would be willing to bet that I'll be able to beat the distance from 30MPH that Edmunds finds most 2008 model cars stopping at (referenced above). Any takers on guessing how long it'll take me to stop from 30MPH (using rim brakes, not that it's relevant) tonight? Anyone want to bet on whether can stop under within 30 feet, which is unarguably faster than most cars (going way back to the start of this whole thing)? I'm trying to think of a fun bet, maybe a set of Koolstop salmon brake pads (I'm looking at you on that one Brent) or a gift certificate for a coffee? Also, Brent, I'm still very curious to hear you describe your max braking technique. How much of the lever(s) do you pull in, which levers, body position, does the rear wheel unweight or lift, etc? I'm surprised by the variation in your stopping distances as well, 39 feet to 56.3 feet is a huge spread. > On Jul 10, 1:45 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > wrote: [quoted text clipped - 9 lines] >> FOR A BICYCLE WITH DISC BRAKES. A typical bicycle doesn't have disc >> brakes. > I thought we were talking about absolute minimum stopping distances > for all vehicles in question, including bikes? Not theoretical calculations! That web site is put numbers in and then it does some theoretical calculation of the minimum. At least follow the farking links first! > the bike I plan to perform my tests on has rim brakes. I'm very > confident I will stop far shorter than you did, and would be willing > to bet that I'll be able to beat the distance from 30MPH that Edmunds > finds most 2008 model cars stopping at (referenced above). As soon as you start skidding and lifting the rear wheel watch your stopping distances increase. > Any takers on guessing how long it'll take me to stop from 30MPH > (using rim brakes, not that it's relevant) tonight? 60+ft based on the results I got last night if you skid/lift the rear wheel. > Anyone want to bet on whether can stop under within 30 feet, which is > unarguably faster than most cars (going way back to the start of this > whole thing)? I'm trying to think of a fun bet, maybe a set of > Koolstop salmon brake pads (I'm looking at you on that one Brent) or a > gift certificate for a coffee? I'm not going to put any material items on what comes down to one's word. That just gives real incentive to cheat. > Also, Brent, I'm still very curious to hear you describe your max > braking technique. How much of the lever(s) do you pull in, which > levers, body position, does the rear wheel unweight or lift, etc? I'm > surprised by the variation in your stopping distances as well, 39 feet > to 56.3 feet is a huge spread. I was going by feel trying for the edge of lock of the rear wheel. I got it the first time. (I even re-measured that one) The other times I got lock and backed off so I wouldn't fall or skid the tread off the tire. I was in my normal upright riding posistion. I don't like riding in the drop. On Jul 10, 4:35 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > On Jul 10, 1:45 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > > wrote: [quoted text clipped - 15 lines] > it does some theoretical calculation of the minimum. At least follow the > farking links first! I'm aware. I'm still curious to conduct my own experiment, is that so wrong? > > the bike I plan to perform my tests on has rim brakes. I'm very > > confident I will stop far shorter than you did, and would be willing [quoted text clipped - 3 lines] > As soon as you start skidding and lifting the rear wheel watch your > stopping distances increase. Why would the distance increase once the rear wheel is lifted? At that point hasn't the front wheel taken any extra braking force the rear could have applied? > > Any takers on guessing how long it'll take me to stop from 30MPH > > (using rim brakes, not that it's relevant) tonight? > > 60+ft based on the results I got last night if you skid/lift the rear > wheel. I'll be shocked if it's 60+ feet. It may be (and seems it will be) over 30, but 60? That's 21 more than your best from 25MPH, quite an increase. Could very well be. We'll see what I get for numbers. In light of the new info provided by MTR, my guess is 40ft. > > Anyone want to bet on whether can stop under within 30 feet, which is > > unarguably faster than most cars (going way back to the start of this [quoted text clipped - 4 lines] > I'm not going to put any material items on what comes down to one's > word. That just gives real incentive to cheat. Fair enough. You don't have any friends in my neck of the woods, do you? Anyway, at this point I figure I will lose the bet, and am perfectly content betting nothing. At least I'm getting guesses now, makes it all a little more fun. I'm still curious what my stopping distances will be. I'll check and be honest, you can choose to believe or ignore my results. No skin off my back either way. > > Also, Brent, I'm still very curious to hear you describe your max > > braking technique. How much of the lever(s) do you pull in, which [quoted text clipped - 7 lines] > was in my normal upright riding posistion. I don't like riding in the > drop. Thanks for the reply. If your weight had been way back off the saddle do you think you would have been able to stop any shorter? > On Jul 10, 4:35 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > wrote: >> As soon as you start skidding and lifting the rear wheel watch your >> stopping distances increase. > Why would the distance increase once the rear wheel is lifted? At > that point hasn't the front wheel taken any extra braking force the > rear could have applied? To put it simply and crudely, because you're not going to want to plant your face in the pavement. >> > Any takers on guessing how long it'll take me to stop from 30MPH >> > (using rim brakes, not that it's relevant) tonight? >> 60+ft based on the results I got last night if you skid/lift the rear >> wheel. > I'll be shocked if it's 60+ feet. It may be (and seems it will be) > over 30, but 60? That's 21 more than your best from 25MPH, quite an > increase. Could very well be. We'll see what I get for numbers. In > light of the new info provided by MTR, my guess is 40ft. My best was _WITHOUT_ skidding. You only need to go five feet longer for 4mph faster _WITH_ skidding. >> I was going by feel trying for the edge of lock of the rear wheel. I got >> it the first time. (I even re-measured that one) The other times I got >> lock and backed off so I wouldn't fall or skid the tread off the tire. I >> was in my normal upright riding posistion. I don't like riding in the >> drop. > Thanks for the reply. If your weight had been way back off the saddle > do you think you would have been able to stop any shorter? I haven't ridden a bicycle small enough for me to pull that trick in ages. And I couldn't get one like that up to 30mph these days either. On Jul 10, 4:59 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > On Jul 10, 4:35 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > > wrote: [quoted text clipped - 6 lines] > To put it simply and crudely, because you're not going to want to plant > your face in the pavement. I am of the impression you've achieved maximum braking when you've fully unweighted the rear tire. I can comfortable stop on the front wheel alone, rear wheel hovering. > >> > Any takers on guessing how long it'll take me to stop from 30MPH > >> > (using rim brakes, not that it's relevant) tonight? [quoted text clipped - 7 lines] > My best was _WITHOUT_ skidding. You only need to go five feet longer for > 4mph faster _WITH_ skidding. Where did skidding come into play? I don't even intend to touch my rear brakes, much less skid. > >> I was going by feel trying for the edge of lock of the rear wheel. I got > >> it the first time. (I even re-measured that one) The other times I got [quoted text clipped - 6 lines] > I haven't ridden a bicycle small enough for me to pull that trick in > ages. And I couldn't get one like that up to 30mph these days either. Think mountain bike. I still have a BMX, however, and I think it tops out right around 30mph. Not much of a stopper though, being rear- brake only. > On Jul 10, 4:59 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > wrote: >>> Why would the distance increase once the rear wheel is lifted? At >>> that point hasn't the front wheel taken any extra braking force the >>> rear could have applied? >> To put it simply and crudely, because you're not going to want to plant >> your face in the pavement. > I am of the impression you've achieved maximum braking when you've > fully unweighted the rear tire. I can comfortable stop on the front > wheel alone, rear wheel hovering. As you apply the front brake, you increase force to the point that the rear wheel starts coming off the ground. Ideally you would want to keep the application force constant at that point, but in reality, it's hard not to decrease the amount of force applied. That in itself would increase braking distance to some extent. >As you apply the front brake, you increase force to the point that the >rear wheel starts coming off the ground. Ideally you would want to keep >the application force constant at that point, but in reality, it's hard >not to decrease the amount of force applied. That in itself would >increase braking distance to some extent. The ideal for a bicycle would be to hold the front brake at the point such that when the bicycle stops, you just reach the tipping point at which the bicycle flips over. All things being perfect, you'd actually stop with the bicycle balanced over the front wheel (but since that's an unstable equilibrium, it isn't going to happen) SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. > On Jul 10, 4:59 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > wrote: [quoted text clipped - 9 lines] >> To put it simply and crudely, because you're not going to want to plant >> your face in the pavement. > I am of the impression you've achieved maximum braking when you've > fully unweighted the rear tire. I can comfortable stop on the front > wheel alone, rear wheel hovering. You've achieved it and past it by. >> >> > Any takers on guessing how long it'll take me to stop from 30MPH >> >> > (using rim brakes, not that it's relevant) tonight? [quoted text clipped - 4 lines] >> > increase. Could very well be. We'll see what I get for numbers. In >> > light of the new info provided by MTR, my guess is 40ft. >> My best was _WITHOUT_ skidding. You only need to go five feet longer for >> 4mph faster _WITH_ skidding. > Where did skidding come into play? I don't even intend to touch my > rear brakes, much less skid. Front brake only eh... your fastest possible stop is a face plant. >> >> I was going by feel trying for the edge of lock of the rear wheel. I got >> >> it the first time. (I even re-measured that one) The other times I got [quoted text clipped - 6 lines] >> I haven't ridden a bicycle small enough for me to pull that trick in >> ages. And I couldn't get one like that up to 30mph these days either. > Think mountain bike. I still have a BMX, however, and I think it tops > out right around 30mph. Not much of a stopper though, being rear- > brake only. I don't drive or ride SUVs. On Jul 10, 7:05 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > Front brake only eh... your fastest possible stop is a face plant. Probably... but that's irrelevant to the discussion, since it's faster than your asinine braking technique when applied just below the threshold of a face plant. But, nice try at applying your typical nirvana fallacy. http://www.csbomb.com/images/stoppie.jpg > I don't drive or ride SUVs. You really don't "drive" or "ride" anything, you only "steer". (I'd give you about 30' at 30mph, Dan.) ----- - gpsman On Jul 10, 7:05 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > > On Jul 10, 4:59 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> > > wrote: [quoted text clipped - 14 lines] > > You've achieved it and past it by. How so? Please explain. > >> >> > Any takers on guessing how long it'll take me to stop from 30MPH > >> >> > (using rim brakes, not that it's relevant) tonight? [quoted text clipped - 10 lines] > > Front brake only eh... your fastest possible stop is a face plant. Without question. And if we allow over-the-bar tumbles (which still won’t equal a face plant, at least with me riding), I guarantee I can out stop most cars, and stop well under 30'. Being an experienced rider, however, I am able to brake hard enough to lift the rear wheel for some time without going over the bars. I do it on a regular basis. Kinda fun, and it facilitates a very short stop (even without the face plant). So, considering I can brake hard enough with the front to unweight the rear without going over the bars, please explain where skidding comes into play or how I'd stop any faster using the rear brake. > >> >> I was going by feel trying for the edge of lock of the rear wheel. I got > >> >> it the first time. (I even re-measured that one) The other times I got [quoted text clipped - 11 lines] > > I don't drive or ride SUVs. Ever hear of the right tool for the job? I do a lot of my riding off- road, on very technical trails. What type of bike would you suggest for that style of riding? As an aside, my bad knee was swelled up ~3 times more than usual when I got home last night, so I skipped the experiment in favor of icing down the knee. I brought the mountain bike today and plan to tool home slowly, using the gears to maintain a proper cadence for a leisurely ride (mostly off-road - again - right tool for the job) tonight, so I should be in reasonable shape to execute the experiment tonight. >> > I am of the impression you've achieved maximum braking when you've >> > fully unweighted the rear tire. I can comfortable stop on the front [quoted text clipped - 3 lines] > > How so? Please explain. If you were correct, that means the rear brake and rear wheel would be entirely useless for slowing. If the brake were useless it would be deleted to save weight. Once you've weight shifted everything on to the front wheel you've past the point of maximum braking because now the rear wheel is doing nothing. >> > Where did skidding come into play? I don't even intend to touch my >> > rear brakes, much less skid. >> Front brake only eh... your fastest possible stop is a face plant. > Without question. And if we allow over-the-bar tumbles (which still > won?t equal a face plant, at least with me riding), I guarantee I can [quoted text clipped - 3 lines] > basis. Kinda fun, and it facilitates a very short stop (even without > the face plant). I don't think you're stopping as fast as you think you are. And I simply cannot fathom under what math a one wheel stop is better than two wheel stop. If it were true we could delete rear brakes on passenger cars and bicycles. > So, considering I can brake hard enough with the front to unweight the > rear without going over the bars, please explain where skidding comes > into play or how I'd stop any faster using the rear brake. First I said skidding _AND_ lifting. Unless you're going to shift your weight over the handlebars to intentionally lift the rear wheel it's going to skid before it lifts unless you don't use the rear brake. If you're not going to use the rear brake forget about minimum stopping distance. >> I don't drive or ride SUVs. > Ever hear of the right tool for the job? I do a lot of my riding off- > road, on very technical trails. What type of bike would you suggest > for that style of riding? 'techincal trails' is that to say trails that are purposely designed for mountain bike entertainment riding? I suppose you'll need one for jumping and other such things. However, I've never found an actual trail that was designed to be used to get from A to B that I could not take a road bike over. And that includes the rocky thing in Iowa that was called a trail to get to the top of the bluff along the miss. river. >If you were correct, that means the rear brake and rear wheel would be >entirely useless for slowing. They are not useless for slowing. They are useless for a maximum-effort stop. >If the brake were useless it would be deleted to save weight. I'm sure that in many racing categories if they weren't required by the rules they'd be deleted. >Once you've weight shifted everything >on to the front wheel you've past the point of maximum braking because >now the rear wheel is doing nothing. It doesn't matter that the rear wheel is doing nothing. The braking force on the front wheel has been increased by as much as braking force on the rear wheel has been decreased. >I don't think you're stopping as fast as you think you are. And I simply >cannot fathom under what math a one wheel stop is better than two wheel >stop. If it were true we could delete rear brakes on passenger cars and >bicycles. Passenger cars do not shift weight forward enough during maximum braking to unweight the rear wheels, so they still need rear brakes for a maximum effort stop. >jumping and other such things. However, I've never found an actual >trail that was designed to be used to get from A to B that I could not >take a road bike over. And that includes the rocky thing in Iowa that >was called a trail to get to the top of the bluff along the miss. river. You'd take a road bike over gravel? A touring bike, sure, but a road bike with 25x700c tires inflated to 100+psi? SignatureThere's no such thing as a free lunch, but certain accounting practices can result in a fully-depreciated one. On Jul 11, 3:58 pm, russo...@grace.speakeasy.net (Matthew T. Russotto) wrote: > You'd take a road bike over gravel? A touring bike, sure, but a > road bike with 25x700c tires inflated to 100+psi? I often ride on a gravel alley near my house because it saves me from having to cross a four lane road. granted it's only ab lock long but no worries. I think my tires are actually 32s but I've been thinking of trying narrower ones (my bike is a CX model because I wanted a road- feeling bike that could be abused and smacked around, and ridden on semi-rough trails without worry) nate >>If you were correct, that means the rear brake and rear wheel would be >>entirely useless for slowing. > They are not useless for slowing. They are useless for a > maximum-effort stop. Not at all if you want to remain stable. >>If the brake were useless it would be deleted to save weight. > I'm sure that in many racing categories if they weren't required by > the rules they'd be deleted. >>Once you've weight shifted everything >>on to the front wheel you've past the point of maximum braking because >>now the rear wheel is doing nothing. > It doesn't matter that the rear wheel is doing nothing. The braking > force on the front wheel has been increased by as much as braking > force on the rear wheel has been decreased. Either the rear wheel starts coming around on you like the rear end of a car or the motion changes into roation of the frame and rider about the front wheel. >>I don't think you're stopping as fast as you think you are. And I simply >>cannot fathom under what math a one wheel stop is better than two wheel >>stop. If it were true we could delete rear brakes on passenger cars and >>bicycles. > Passenger cars do not shift weight forward enough during maximum braking to > unweight the rear wheels, so they still need rear brakes for a maximum > effort stop. On they do become unweighted enough that the rear of the car starts coming around and/or the rear lifts up on the suspension. I'll wager that if the rear end did not have a suspension but was solidly mounted like a bicycle's wheels we'd see lift of the wheels off the ground. The suspension travel and spring displacement simply takes up the motion. >>jumping and other such things. However, I've never found an actual >>trail that was designed to be used to get from A to B that I could not >>take a road bike over. And that includes the rocky thing in Iowa that >>was called a trail to get to the top of the bluff along the miss. river. > You'd take a road bike over gravel? A touring bike, sure, but a > road bike with 25x700c tires inflated to 100+psi? I've ridden road bikes on gravel many times. One of the through the forest preserve bike trails I use because it actually goes somewhere is a fine gravel. Not that I haven't ridden on the larger stuff. I don't like it, it's not pleasant when the stones are larger but I can do it. When I was in the 4th grade or so I wanted one of what are now called mountain bikes. Back then they were dirt bikes with gears. Anyway they were more money than a regular road ten-speed so I had to settle for a road going ten-speed. I road it on the trails anyway. I learned what I had to do. Now I won't give up the on road handling and speed and I can still ride trails because I know how to navigate them. Sure I can't take a course with jumps and ramps and other nonsense but I never encounter trails that rough. Ok... I decided to think... what's a way to settle this... I started googling for motorcycle testing. I found this: http://www.motorcyclecruiser.com/streetsurvival/advanced_braking/index.html Myth #1: Use Only the Front Brake <...> So, how do you stop in the shortest distance possible? The textbook response states you should achieve full application of both brakes without skidding. As you apply more and more pressure on the front brake (up to the point of lockup), you will have more traction available to the front tire (for more braking) resulting in progressively less traction available to the rear. To keep from skidding the rear wheel, you will need to modulate the rear brake. <...> ------------------------ That's what I was able to do in my shortest run. sadly I cannot find any road tests where braking distances from different speeds were given. But there's enough advantage with motorcycle brakes and tires over a bicycle's that I would guess they would be pretty close to cars. On Jul 11, 8:58 pm, Brent P <tetraethylleadREMOVET...@yahoo.com> wrote: > Ok... > [quoted text clipped - 15 lines] > traction available to the rear. To keep from skidding the rear wheel, > you will need to modulate the rear brake. That's the equivalent of basic driver's ed. Fine for a casual rider, but if you're busting a.s you better have busting a.s stopping skills. The only way to attain busting a.s stopping skills is practice, and becoming comfortable with your rear wheel off the ground. First, you practice from a velocity insufficient to result in a face plant, and progress from there as your balance, coordination, "seat of the pants" feel and courage or stupidity allow. Then you keep practicing. Not at all unlike achieving expertise in any number of disciplines, almost all biking activity can and should be directed toward "practice", with an eye toward the elimination of errors and improvement of technique. You ride through a puddle and ride figure-8s, try to make a single track, etc.; when you have to stop you practice your track stand, and, of course, you can practice maximum braking from any velocity, and should. We used to flatten a pop can and see who could brake their front tire on it and slide the farthest. AAR, you should obtain some biking expertise before purporting yourself as a biking authority. You obviously ain't got none. ----- - gpsman >Ok... > [quoted text clipped - 7 lines] > ><...> In the deleted section: "Unless you are braking so hard that the rear wheel of your motorcycle is in the air, you can shorten your stopping distance wi |
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