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Car Forum / Mazda / Mazda Miata / February 2007NC Precision Alignment
Just got my NC's precision 4-wheel alignment done at Stokes Tire / Santa Monica. Same place I had my NB done. I've been very satisfied with their work. I showed the Tech my NB's specs before alignment. Here are NB and NC specs: NB Initial Final FRONT Lt.Caster 6.18° 5.71° Rt.Caster 6.12° 5.83° Lt.Camber -0.13° -0.96° Rt.Camber -0.38° -0.93° Lt.Toe 0.09° 0.03° Rt.Toe 0.18° 0.03° Total 0.27° 0.06° REAR Lt.Camber -0.87° -1.49° Rt.Camber -1.36° -1.51° Lt.Toe 0.39° 0.08° Rt.Toe -0.08° 0.08° Total 0.31° 0.16° Thrust Angle 0.23° 0.00° ------------ NC Initial Final FRONT Lt.Caster 5.87° 5.65° Rt.Caster 5.64° 5.91° Lt.Camber 0.21° -0.90° Rt.Camber -0.11° -0.87° Lt.Toe 0.11° -0.04° Rt.Toe 0.22° -0.05° Total 0.33° -0.09° REAR Lt.Camber -0.72° -1.63° Rt.Camber -0.96° -1.60° Lt.Toe 0.11° 0.16° Rt.Toe 0.36° 0.16° Total 0.47° 0.32° Thrust Angle -0.13° 0.00° ------------- I just got back from an early-morning run thru twisty Latigo Canyon. Couldn't wait to compare the 2 cars - I drive this canyon a lot. First thing - Oversteer. Rear end of NC is considerably looser, to me. There's one banked hairpin that's good test. You can easily see if anyone's coming (opp. direction), so when it's open, you can take the turn hard-as-you-want. Did this a lot w/NB. Could enter this turn at 35, drift a little, power out. Well, the NC almost changed ends when I did same thing w/it, first-time. Tried again. Little better, but rear end less neutral than NB, kept coming around. Dropped speed into turn - to 25, and I could sorta drift thru, power out. But NC just wasn't as 'sticky' as NB. NB had Michelin Pilot, 195/50R15's. NC: Yokohama Advan A11A, 205/50R16's. Could be the difference? But NC front end stuck, no oversteer at all. So - I don't know. Going back to Stokes for adjustment(?) on Tuesday. Again, same place, same Tech as NB, yet car feels different, looser. First thoughts; NC is heavier. Battery no longer in trunk (way up-front, engine compartment, passenger-side). Is NC *really* a 50-50 wt. distr. car? -- Steve McMahon Green '07 Sport Steve, this statement confuses me; But NC front end stuck, no oversteer at all. So - I don't know. Can you clear this up for me? Also, I'm pretty sure that you're monitoring tire pressures, correct? You know that you can fine tune the understeer / oversteer balance with those tire pressures, right? I mean, you can't fix a bad handling car or change it from understeer to oversteer but you can do the fine tuning once you have the alignment real close. Chris 99BBB > Steve, this statement confuses me; > > But NC front end stuck, no oversteer at all. So - > I don't know. No, not clear, sorry 'bout that. What I meant was that the car never understeered; the front tires never, ever broke adhesion, but the rears did break. So, what I was thinking - if the tires lacked adhesion, then the fronts, as well as rears would break adhesion, at least sometimes? > Can you clear this up for me? I have no experience whatsoever w/Yokohamas. Can't ever remember reading about them in this group. Trying to say that car never 'ploughed' and that if tires weren't that good, then front would break - sometime? Okay - maybe Yokohama A11A's aren't very good tires? I Don't know. > Also, I'm pretty sure that you're monitoring tire pressures, correct? 29lbs. - Mazda recommended pressure. I ran my NB at 28lbs. (30 recommended). So, yeah, I'll probably pull a few lbs., like to 27lbs. for the next run. You > know that you can fine tune the understeer / oversteer balance with those > tire pressures, right? I mean, you can't fix a bad handling car or change > it from understeer to oversteer but you can do the fine tuning once you > have the alignment real close. Yes, sorta what I found w/NB, but the first drive w/precision alignment, if memory serves & I think it does, was better in the NB. Lowered pressure and got more grip, if memory serves. I'm sorta wondering if there's too much toe in or too much neg camber. Haven't beeen able to find anything on NC setup so, kinda guessing. > Chris > 99BBB Thanks much for your input, Chris. any ideas? I'm open. -- SM >> Steve, this statement confuses me; >> [quoted text clipped - 5 lines] >break. So, what I was thinking - if the tires lacked adhesion, then the >fronts, as well as rears would break adhesion, at least sometimes? Not necessarily. Depends on the weight on the wheels and the heating characteristics of the tires. The front tires may be hotter. Anyway, if the rears break out first, how do you judge when the fronts would be doing it? >> Can you clear this up for me? > >I have no experience whatsoever w/Yokohamas. Can't ever remember reading >about them in this group. Trying to say that car never 'ploughed' and that >if tires weren't that good, then front would break - sometime? Okay - maybe >Yokohama A11A's aren't very good tires? They are OEM summer tires, according to tirerack. They have no further info, I would assume they are cheap, since they are the base offering. The tires on my grand touring package are *very good*. Also, it has not much to do with who made them, more with how much Mazda paid for them. Yokohama makes some very good tires, but at a price. I still remember the horrible tires that came on my 96 in my nightmares. Bridgerocks. > I Don't know. > >> Also, I'm pretty sure that you're monitoring tire pressures, correct? > >29lbs. - Mazda recommended pressure. I ran my NB at 28lbs. (30 >recommended). The NA has 26 recommended. I did not know Mazda changed it that much on the NB? > So, yeah, I'll probably pull a few lbs., like to 27lbs. for >the next run. I would assume you would want to *increase* tire pressure on the rear, rather than reduce it? Why do you want to reduce from the OEM setting which no doubt is based on comfort? If you go still lower, wheel or tire damage become more likely? >You >> know that you can fine tune the understeer / oversteer balance with those [quoted text clipped - 5 lines] >memory serves & I think it does, was better in the NB. Lowered pressure and >got more grip, if memory serves. What month was that? >I'm sorta wondering if there's too much toe in Too much toe *in*? I would probably try to *increase* toe in in the rear a bit after putting front toe to zero, if it was me. But it may kill your tires. > or too much neg camber. Reducing front negative camber a bit might help I would think. >Haven't beeen able to find anything on NC setup so, kinda guessing. Mazda gives different numbers for car height, but as usual, there is so much slop that you wonder why they bother. Leon >> Chris >> 99BBB > >Thanks much for your input, Chris. any ideas? I'm open.  SignatureLeon van Dommelen :) Bess, the Miata :) Bozo, the Miata :) rammm@dommelen.net http://www.dommelen.net/miata The only thing better than a white Miata is two white Miatas >> So, yeah, I'll probably pull a few lbs., like to 27lbs. for >>the next run. [quoted text clipped - 3 lines] > which no doubt is based on comfort? If you go still lower, wheel or > tire damage become more likely? I thought that decreasing, in-creased grip - thinking that making tire 'softer' put more rubber-on-road. Seemed to me that in-creasing pressure, making tire 'harder', would de-crease grip. Just going on self-logic & experience here, not tech expertice - at all (have none). You're saying the opposite is true? Honestly curious 'bout this. Why does more pressure yield more grip? Thanx. >>Yes, sorta what I found w/NB, but the first drive w/precision alignment, >>if [quoted text clipped - 3 lines] > > What month was that? Feb. of 2002. Can't remember weather but know it was dry. Think it was pretty much like weather we're having now. >>I'm sorta wondering if there's too much toe in > > Too much toe *in*? I would probably try to *increase* toe in in the rear > a > bit after putting front toe to zero, if it was me. But it may kill your > tires. That is *exactly* what I'm going to tell Tech this week. Zero Front Toe-in, and slight toe-in Rear. Mind-me-asking? How Much Toe-in do you have on Rear? >> or too much neg camber. > > Reducing front negative camber a bit might help I would think. Will do. How much do you think? Thanks so much. Again, would like to know how much Toe-in you have on Rear. -- SM >>> So, yeah, I'll probably pull a few lbs., like to 27lbs. for >>>the next run. [quoted text clipped - 10 lines] >opposite is true? Honestly curious 'bout this. Why does more pressure >yield more grip? Thanx. You are right that if you decrease pressure you put more rubber on the road and that that tends to increase grip. However, the reduced tire pressure causes the sidewalls to roll-over in hard turns, and that kills grip. And the Mazda recommendation is for comfort, meaning soft side walls. I would not go below it. >>>Yes, sorta what I found w/NB, but the first drive w/precision alignment, >>>if [quoted text clipped - 6 lines] >Feb. of 2002. Can't remember weather but know it was dry. Think it was >pretty much like weather we're having now. OK. Temperature is not the reason then. My guess then is mainly tires. >>>I'm sorta wondering if there's too much toe in >> [quoted text clipped - 6 lines] >and slight toe-in Rear. Mind-me-asking? How Much Toe-in do you have on >Rear? IIRC, on my NA, last time I told them to set the toe to zero both ends, (or Lanny's minimum, maybe) since replacing tires is somewhat of a hassle. My NC has whatever Mazda put on there. I have not yet done an alignment. >>> or too much neg camber. >> >> Reducing front negative camber a bit might help I would think. > >Will do. How much do you think? One degree difference seems to work well on my NC (assuming that it is up to Mazda's specifications.) At AutoX it breaks evenly at both ends. The workshop manual specifications are at http://dommelen.net/tmp012.jpg http://dommelen.net/tmp013.jpg http://dommelen.net/tmp014.jpg As far as I am concerned, when I get around doing an alignment, in the absence of a more expert opinion, I will probably give them Mazda's numbers plus another quarter or half degree of camber at both ends. >Thanks so much. Again, would like to know how much Toe-in you have on Rear. Leon SignatureLeon van Dommelen :) Bess, the Miata :) Bozo, the Miata :) rammm@dommelen.net http://www.dommelen.net/miata The only thing better than a white Miata is two white Miatas >Just got my NC's precision 4-wheel alignment done at Stokes Tire / Santa >Monica. Same place I had my NB done. I've been very satisfied with their [quoted text clipped - 38 lines] >Rt.Toe 0.22° -0.05° >Total 0.33° -0.09° You now have toe out in front. Mazda specifies toe in on both front and rear. >REAR >Lt.Camber -0.72° -1.63° >Rt.Camber -0.96° -1.60° Mazda specifies a degree more camber in rear than in front. >Lt.Toe 0.11° 0.16° >Rt.Toe 0.36° 0.16° >Total 0.47° 0.32° Toe-in rear has been reduced. >Thrust Angle -0.13° 0.00° > [quoted text clipped - 13 lines] >NB had Michelin Pilot, 195/50R15's. NC: Yokohama Advan A11A, 205/50R16's. >Could be the difference? That would be my guess. The tires tend to make most of the difference. My NC is *much* more forgiving than my NA; both have performance tires, and my NA has a heavier front sway bar. Increasing the difference between front and rear camber may make some difference. Also, what were the tire pressures? And what was the temperature out there? It is February now. > But NC front end stuck, no oversteer at all. You just said it had? Oversteer does not come per end. > So - >I don't know. [quoted text clipped - 4 lines] >First thoughts; NC is heavier. Battery no longer in trunk (way up-front, >engine compartment, passenger-side). But the engine and fuel tank have been repositioned closer to the center. > Is NC *really* a 50-50 wt. distr. car? According to Mazda literature, the front/rear 50/50 weight distribution is near perfect including driver. Car and driver reports 52%/48%, I assume empty. This is what it was before. Leon SignatureLeon van Dommelen :) Bess, the Miata :) Bozo, the Miata :) rammm@dommelen.net http://www.dommelen.net/miata The only thing better than a white Miata is two white Miatas >>NC >> Initial Final [quoted text clipped - 11 lines] > You now have toe out in front. Mazda specifies toe in on > both front and rear. I agree. Pardon my ignorance, but I thought - (minus) was toe In, so, - (minus) number is Toe Out? So, for Toe-In, I want a positive number? >>REAR >>Lt.Camber -0.72 -1.63 >>Rt.Camber -0.96 -1.60 > > Mazda specifies a degree more camber in rear than in front. I will ask about that. Thanks. >>Lt.Toe 0.11 0.16 >>Rt.Toe 0.36 0.16 >>Total 0.47 0.32 > > Toe-in rear has been reduced. Again, I had this backwards. Going to clear this up Tuesday. I want toe-In F/R. >>NB had Michelin Pilot, 195/50R15's. NC: Yokohama Advan A11A, 205/50R16's. >>Could be the difference? > > That would be my guess. The tires tend to make most of the difference. > My NC is *much* more forgiving than my NA; both have performance tires, > and my NA has a heavier front sway bar. What are you running on your NC? > Increasing the difference between front and rear camber may make some > difference. Also, what were the tire pressures? And what was the > temperature out there? It is February now. 29lbs. - Mazda spec. About 64-degrees this morning. I drove it once up/don to heat up tires before run. Going to lower pressure to 27lbs. >> But NC front end stuck, no oversteer at all. > > You just said it had? Oversteer does not come per end. Sorry - yeesh! - I meant 'under'steer. Front end 'ploughing'. Never saw understeer. My Mistake. >> Is NC *really* a 50-50 wt. distr. car? > > According to Mazda literature, the front/rear 50/50 weight distribution > is near perfect including driver. Car and driver reports 52%/48%, I > assume empty. This is what it was before. I read somewhere that elimination of hidden headlights rendered 50-50 in the NB. The rear end felt 'heavier' to me. Sorta like an Old Porsche (not as bad). thanx to all -- SM >>>NC >>> Initial Final [quoted text clipped - 14 lines] >I agree. Pardon my ignorance, but I thought - (minus) was toe In, so, - >(minus) number is Toe Out? So, for Toe-In, I want a positive number? http://en.wikipedia.org/wiki/Toe_(automotive) It is always confusing me too. But looking at my Custom Alignment printouts, rear toe is listed as positive and front toe as negative. I gave them Millman's alignment at the time so negative is listed by these machines as out. >>>REAR >>>Lt.Camber -0.72 -1.63 [quoted text clipped - 21 lines] > >What are you running on your NC? 29 to 31 psi at AutoX, depending on whether I get around adding some air. >> Increasing the difference between front and rear camber may make some >> difference. Also, what were the tire pressures? And what was the [quoted text clipped - 20 lines] >I read somewhere that elimination of hidden headlights rendered 50-50 in the >NB. Then the driver weight would presumably change it to 48/52? So you would have a bit more weight on the rear wheels in the NB. >The rear end felt 'heavier' to me. Sorta like an Old Porsche (not as bad). > >thanx to all Leon SignatureLeon van Dommelen :) Bess, the Miata :) Bozo, the Miata :) rammm@dommelen.net http://www.dommelen.net/miata The only thing better than a white Miata is two white Miatas What diffs are the two cars running? Open, Torsen or LSD? Could make a *big* differance drifting. Both models had several diff options. > Just got my NC's precision 4-wheel alignment done at Stokes Tire / Santa > Monica. Same place I had my NB done. I've been very satisfied with their [quoted text clipped - 77 lines] > Steve McMahon > Green '07 Sport > What diffs are the two cars running? Open, Torsen or LSD? Could make a > *big* differance drifting. Both models had several diff options. NB: Torsen NC: Open But have had several (mostly) open diff cars, so I'm aware of wheel spin coming out of turn, straightening w/power. Going to switch out diffs as soon as a '06/'07 LSD shows up at local boneyard. -- SM >> What diffs are the two cars running? Open, Torsen or LSD? Could make a >> *big* differance drifting. Both models had several diff options. > >NB: Torsen > >NC: Open I of course have Torsen. Maybe that is indeed the difference. I wanted to mention it earlier and then I forgot. Though I do not understand why it would make much of a difference without applying power; I thought the Torsen only did something if there was a noticeable torque difference between wheels. Leon >But have had several (mostly) open diff cars, so I'm aware of wheel spin >coming out of turn, straightening w/power. > >Going to switch out diffs as soon as a '06/'07 LSD shows up at local >boneyard. SignatureLeon van Dommelen :) Bess, the Miata :) Bozo, the Miata :) rammm@dommelen.net http://www.dommelen.net/miata The only thing better than a white Miata is two white Miatas Steve, I won't jump into the alignment fray as these guys are much more comfortable with the 'add this, gets you that' kind of stuff and for me, I have to go back thru it making notes and such to re-learn it each time I get back into it but, my bad memory is another story all together. My comment is in reference to the tire pressure issue. My understanding (and experience) tells me that you are correct in your belief that relatively lower pressure adds grip and relatively higher pressure reduces grip. This isn't universal so let's not go there but, in the situation we are talking about here, it does apply. While Leon is correct that decreased pressure will add a bit to the tires tendancy to 'rollover' when pushed sideways, it's my belief / understanding that rollover is less affected by these small differences in inflation than grip. Point being that rollover is more a factor of the design / construction of a particular tire than the exact tire pressure. After all, we're talking about increments of 2~3 lbs here. Remember that we're talking about running front and back pressures different, it's the difference that changes the cars handling characteristics. If you're worried that dropping a couple lbs in the rear will be a problem, you can get a similar effect by bumping the fronts up a bit. When autocrossing, similar to performance driving on the street, the miata has plenty of grip on the front tires. This allows bumping pressure up quite a bit. Most miata a-x'ers that I know, run 34~38lbs because they still have sufficient grip up front and by doing this, they decrease the tires response / turn-in time. When I started autocrossing the NB it had much more tendancy to understeer at the limit than my old modified 92 so I had to soften the front shock settings, stiffen the rears AND bump the rear tire pressures before I could get it to 'come around' like I wanted it to. With the NC, you're in barely chartered waters, keep us posted guys! Chris 99BBB |
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