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Car Forum / Subaru Cars / January 2007Tire profile vs tire performance
All that alloy vs steel business got me thinking (plus a guy bitching on the ford newsgroup about the lack of 80 profile tires): why there are no high profile high performance tires? I think RE960 which is not exactly the top performer cuts off at 60 and I think the tallest RE950 was 70 (for 14" rims). Do Americans perceive sidewall flex as a real problem or something? Is that a real problem? Someone mentioned that the sidewall on tires of Formula 1 cars is pretty high and I think you can get the same brake disk performance by making it fatter versus larger in diameter so the breaks argument does not fly wery well. The reason I'm asking is because 13-15" alloys should weight way less than 17-18" alloys and 185/60 HR14 RE960 is 18 lbs vs 32 lbs for 285/30 ZR20 Looks like the tire weight is almost directly proportional to the width with the sidewall responsible for the "almost" part. For 285mm W 60 profile tire with outer diameter (OD) of 26.8" I'd need a 13" rim: 26.8" - (286mm x 60 x 2 / 100 / 25.4)=26.8 - 13.6 =13.2" Needless to say there are no ultra high performance all seasons. let alone max performance in 286/60 R13 size. Heck, I think there are no street tires in that size period. Is the reason the "performance" looks or low profile tires for the rice boys??? Any links to the articles over a few paragraph in length on F1 tires? > All that alloy vs steel business got me thinking (plus a guy bitching > on the ford newsgroup about the lack of 80 profile tires): [quoted text clipped - 28 lines] > > Any links to the articles over a few paragraph in length on F1 tires? Good question. My 'guesses' would be ; too limiting on the 'swept area' of the brakes(probably a 'fatness'- if you meant 'arc length'/whatever - limit for clearing gasses and dust) and ,again - maybe, the sidewall thickness starts adding weight or other factors (more heat?) detrimental to the 'system'. Interesting. I have read of 1 or 2 autox-ers that stay with 16s saying there's no improvement going to 17s, and likely 16s for rallyx would help in rim longevity but I guess construction factors and course topography play as big a roll. hmmm...yeah, I'd like to know too. Carl  Signatureto reply, change ( .not) to ( .net) > > All that alloy vs steel business got me thinking (plus a guy bitching > > on the ford newsgroup about the lack of 80 profile tires): [quoted text clipped - 34 lines] > thickness starts adding weight or other factors (more heat?) detrimental > to the 'system'. Interesting. According to the tirerack tech archive the sidewall is typically 100% polyester. http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=9¤tpage=38 > I have read of 1 or 2 autox-ers that stay with 16s saying there's no > improvement going to 17s, and likely 16s for rallyx would help in rim > longevity but I guess construction factors and course topography play as > big a roll. Well, slotted rotors work better within the same rotor diameter and going from 16" to 17" allows for a 1" increase in rotor size so if you have 10" rotor with 16" and you can now clear 11" rotor you have 11x11 / (10x10) = 21% greater area to dissipate heat. I just don't understand why can't they just make a 21% fatter rotor. WRX has 24mm rotors and STI has 30mm. Granted, STI rotor diameter is larger, but there is nothing that prevents Brembo from making say 45 mm rotors. Would that require using wheels with larger offset to clear fatter calipers? Any pictures/drawings of wheel/tire/brake cross section of a Formula 1 car? > Do Americans perceive sidewall flex as a real problem or something? > Is that a real problem? Someone mentioned that the sidewall on tires of > Formula 1 cars is pretty high and I think you can get the same > brake disk performance by making it fatter versus larger in diameter > so the breaks argument does not fly wery well. Formula 1 wheels are fixed in size by the regulations, to enforce reduced performance. Combined with very very stiff suspension setups, the result is that a large percentage of the suspension travel on an F1 car is in the sidewall of the tyre, which is undamped. AIUI this makes the transient behaviour of the car much more difficult to model and control. Therefore, you probably would not want to take this route with a road car. SignaturePhil http://www.usefilm.com/photographer/31307.html >> Do Americans perceive sidewall flex as a real problem or something? >> Is that a real problem? Someone mentioned that the sidewall on tires of [quoted text clipped - 9 lines] > control. Therefore, you probably would not want to take this route with > a road car. Makes sense. Carl Signatureto reply, change ( .not) to ( .net) > > Do Americans perceive sidewall flex as a real problem or something? > > Is that a real problem? Someone mentioned that the sidewall on tires of [quoted text clipped - 9 lines] > control. Therefore, you probably would not want to take this route with > a road car. It's an extremely wide 13" rim. Apparently the width is allowed to vary. I mean - they allow rims that are wider than their height. I also read that the wheel makers often won't deliver their wheels to F1 teams until they get their final tires, maybe a few weeks before the start of the season. And steel seem to be legal. Apparently F1 teams don't subscribe to Jiri's logic that steel is good enough. Really - a magnesium alloy is probably the ideal material for its light weight and stiffness. <http://fia.com/resources/documents/119845428__21_12_2005_F1_regs_2008_fnl.pdf> "12.3 Wheel material : All wheels must be made from an homogeneous metallic material. 12.4 Wheel dimensions : 12.4.1. Complete wheel width must lie between 345mm and 365mm when fitted to the front of the car and between 440mm to 460mm when fitted to the rear." > It's an extremely wide 13" rim. Apparently the width is allowed to > vary. I mean - they allow rims that are wider than their height. Yeah, the tyres are very wide, because they have a lot of power to put down, and they're grooved, because allowing narrower tyres would significantly reduce drag, increasing top speeds, which is Not Safe. IANA vehicle dynamicist, so I can't tell you what aspect ratio does to tyre dynamics. F1 wheels and tyres, like much of F1, are determined much more by the rulebook than by the technical ideal, which would be more like what Peugeot have fitted to the 908 LMP1 race car. They probably have some rules on wheels but LMP1 is more flexible than F1, I think. SignaturePhil http://www.usefilm.com/photographer/31307.html > > It's an extremely wide 13" rim. Apparently the width is allowed to > > vary. I mean - they allow rims that are wider than their height. [quoted text clipped - 6 lines] > more by the rulebook than by the technical ideal, which would be more > like what Peugeot have fitted to the 908 LMP1 race car. They probably What wheels sizes and tires are used on 908 and how are brakes cooled on LMP cars? it looks like the fit in the wheel wells is tight with not much airflow > What wheels sizes and tires are used on 908 and how are brakes cooled > on LMP cars? it looks like the fit in the wheel wells is tight with not > much > airflow I don't know what size the wheels are, sorry. The only detail on the Peugeot Sport website is that they're BBS magnesium wheels - the website doesn't have photos of the real car though, so perhaps the technical details will be updated at some point. Brake cooling will be achieved by ducting air into the wheel well from the two channels that run between the wheelarches and the nose - if you look at the photos of the front on www.motorsport.com you can see the brake duct intakes. The air is then vented through the alloys and out sideways. SignaturePhil http://www.usefilm.com/photographer/31307.html > 12.4 Wheel dimensions : > 12.4.1. Complete wheel width must lie between 345mm and 365mm > when fitted to the front of the car and between 440mm to 460mm > when fitted to the rear." And how does the wheel know where has it been fitted to? In article <1168401278.316712.215920 @i39g2000hsf.googlegroups.com>, aglyport@gmail.com says... > Do Americans perceive sidewall flex as a real problem or something? > Is that a real problem? You're joking, right? >In article <1168401278.316712.215920 >@i39g2000hsf.googlegroups.com>, [quoted text clipped - 3 lines] > >You're joking, right? ...'Why aren't anyone using square tires?' Signature"...Luigi follow only the Ferraris." In article <13efq29micc0mij2c3auqc1o9c3vgimams@ 4ax.com>, tifoso@mindspring.com says... > >In article <1168401278.316712.215920 > >@i39g2000hsf.googlegroups.com>, [quoted text clipped - 5 lines] > > ...'Why aren't anyone using square tires?' It's tough to take a question like that seriously--particularly from a nick like "bodyroll". > All that alloy vs steel business got me thinking (plus a guy bitching > on the ford newsgroup about the lack of 80 profile tires): > why there are no high profile high performance tires? > I think RE960 which is not exactly the top performer cuts off at 60 > and I think the tallest RE950 was 70 (for 14" rims). I'd have to say because a tall sidewall is the opposite of what a performance tire is, which is all about sidewall flex. Even in a straight line, a tall sidewall will flex more than a low profile one will (think of a brush and then cut the bristles in half and check the stiffness again.) Flex = heat. Heat is bad. Ironically, if you check the hardness on most "high performance" tires with a Z or Y speed rating, you'll find the rubber is rock hard at room temperature so they don't come apart under sustained high speeds. I have one question -> what do YOU define a high performance tire as? if you're defining it based on speed rating, then see my comments re:sidewall flex. These are high performance tires and are completely different designs: 1-Ice racing tires. 2-Drag racing tires. 3-Tires designed for autocrossing. 4-Tires designed for a 500 mile endurance race. 1-soft tread compound at -30 2-soft sidewalls for maximum launch 4-designed to get sticky with minimal warmup 5-designed to handle heat from extended high speed running. heck, even in NASCAR they use different compounds at different tracks. They even have right side and left side tires for ovals. Ray > > All that alloy vs steel business got me thinking (plus a guy bitching > > on the ford newsgroup about the lack of 80 profile tires): [quoted text clipped - 12 lines] > the rubber is rock hard at room temperature so they don't come apart > under sustained high speeds. Good point. I'll get the tires with the lowest speed rating that the tire shop would sell. Thanks! > I have one question -> what do YOU define a high performance tire as? for max performance summer tires I'd define it as "grips tenaciously to the wet pavement at the temperatures above 45F" and speeds in 0-120 mph range. Ventus R-S2 and Ecsta MX worked well for me. Drooling over F1 GS D3 now. > if you're defining it based on speed rating, then see my comments > re:sidewall flex. I could see how that could be a problem on the track with the average speeds in triple digits, but don't see how that helps in driving on public roads. > These are high performance tires and are completely different designs: > 1-Ice racing tires. [quoted text clipped - 6 lines] > 4-designed to get sticky with minimal warmup > 5-designed to handle heat from extended high speed running. How are ice racing tires different from "performance winter" and "studless winter" tires for the street? > heck, even in NASCAR they use different compounds at different tracks. > They even have right side and left side tires for ovals. Ok. My curiosity is all about the technology carryover and applicability to the street legal tires. > Good point. I'll get the tires with the lowest speed rating > that the tire shop would sell. Thanks! they sell tools to measure the rubber "softness" - but that's not always the best indicator either, because room temperature hardness doesn't always translate to operating temperature hardness, and unfortunately, you have no cheap way to "test" multiple brands of tires on your own car... >> I have one question -> what do YOU define a high performance tire as? >> > for max performance summer tires I'd define it as "grips tenaciously > to the wet pavement at the temperatures above 45F" and speeds > in 0-120 mph range. Ventus R-S2 and Ecsta MX worked well > for me. Drooling over F1 GS D3 now. fwiw, I have the Ecsta MX's on my Trans Am. They weren't any better than the OEM Goodyear Eagle F1's. Probably worse. IOW, I won't be replacing them with another set. And I define high performance street tire as dry grip, which is why my next set of tires for it will be BFG KD's. Not the KDW, because I try not to drive it in the rain. >> if you're defining it based on speed rating, then see my comments >> re:sidewall flex. [quoted text clipped - 3 lines] > in triple digits, but don't see how that helps in driving on public > roads. well, I saw rec.autos.sport.f1 in the newsgroup line... >> These are high performance tires and are completely different designs: >> 1-Ice racing tires. [quoted text clipped - 9 lines] > How are ice racing tires different from "performance winter" and > "studless winter" tires for the street? I was comparing them against each other - they are all a high performance tire yet other than being black and round are completely different applications. > Ok. My curiosity is all about the technology carryover and > applicability > to the street legal tires. I see. If it's any consolation, tire selection and pressure is a black art if I ever saw one. Ray > >> I have one question -> what do YOU define a high performance tire as? > >> [quoted text clipped - 5 lines] > than the OEM Goodyear Eagle F1's. Probably worse. IOW, I won't be > replacing them with another set. I can't tell much of a difference between Ventus R S2 and Ecsta MX and that's 5th vs 15th place in C&D test. Haven't tried F1 GS D3 yet. F1 GS D3 is significantly more expensive and is not available in 195 55 R15. My only choice now is to put them on outback nadasport but suspension is so soft it very silly to do that. RE-960s for me? > And I define high performance street tire as dry grip, which is why my > next set of tires for it will be BFG KD's. Not the KDW, because I try > not to drive it in the rain. Do KD offer noteceably more grip than KDW in the dry? Do you know of they break away in a controllable fashion in the wet? > >> if you're defining it based on speed rating, then see my comments > >> re:sidewall flex. [quoted text clipped - 4 lines] > > roads. > well, I saw rec.autos.sport.f1 in the newsgroup line... I was wondering in the original post if tires with very tall sidewall work in F1 with speeds over 200mph why there are only crappy compounds available for street tires with tall sidewalls and speculating that rice kids are paying for R&D on 18"s with rubber band tires, so the rest of us have to live with those tire sizes as well if we are to get any grip. Probably the consumer retorts public is buying crap like triple treds in high sidewall sizes and there is no demand for 60 or 70 profile f1 gs D3s so Goodyear does not make them in that size? > > How are ice racing tires different from "performance winter" and > > "studless winter" tires for the street? > I was comparing them against each other - they are all a high > performance tire yet other than being black and round are completely > different applications. Haven't seen any tires for racing on ice on tirerack so had to ask what are they. Any model numbers you have in mind or those are one-offs provided directly to the race teams? > > Ok. My curiosity is all about the technology carryover and > > applicability > > to the street legal tires. > I see. > If it's any consolation, tire selection and pressure is a black art if I > ever saw one. It sucks to be left in the dark by the tire companies, isn't it? >> And I define high performance street tire as dry grip, which is why my >> next set of tires for it will be BFG KD's. Not the KDW, because I try >> not to drive it in the rain. >> > Do KD offer noteceably more grip than KDW in the dry? > Do you know of they break away in a controllable fashion in the wet? KD: Number one in dry cornering*. What it is: Track-ready ultra high performance tire with near race-level grip. Multi-time magazine showdown winner. The highest dry cornering mark (1.08g) one leading testing organization has ever recorded for a full tread depth street-legal tire*. Who it’s for: High-performance car owners and weekend track event competitors seeking absolute no-compromise, dry cornering performance. *As of 6/10/04. For additional information go to www.bfgoodrichtires.com/g-Force. KDW: Bringing ultra high performance to more vehicles than any other tire line. What it is: Your go-to ultra high performance tire.With 92 sizes – from 15” to 24” – it covers more car, truck and SUV fitments than any other UHP tire line. Many unique sizes and a choice of tread patterns for ultimate customization. Excellent wet and dry traction. Who it’s for: The vast majority of owners of stock and customized performance cars and trucks seeking outstanding performance and improved appearance. Especially Plus-1, Plus-2, dub and other custom sizes. All I care about is dry grip. You don't want to be driving a KD in the rain. > I was wondering in the original post if tires with very tall sidewall > work [quoted text clipped - 6 lines] > for 60 or 70 profile f1 gs D3s so Goodyear does not make them > in that size? I can't find a tire size on an F1 tire, but it looks low profile to me - a 355/30-15 has a sidewall almost the same height as a 205/50-15... and the tires in F1 are purposely crippled to reduce cornering speeds. You can read about it on formula1.com > It sucks to be left in the dark by the tire companies, isn't it? Oh, they'll all convince you their products are all the best. ;) After going from brand to brand, I'm staying with BFG for the time being until someone can convince me to switch. Ray > I can't find a tire size on an F1 tire, but it looks low profile to me - > a 355/30-15 has a sidewall almost the same height as a 205/50-15... I can never remember the formula, but assuming that for highest grip, the teams fit the biggest wheels allowed, that would mean a rolling diameter of 660mm, with 355mm wide wheels at the front and 380mm wide wheels at the back. The front tyre tread width may not exceed 270mm. I'm actually struggling to find the rule that sets the size of the rims, but I thought they were 13". It must be in the regulations somewhere but for some reason it's eluding me today. SignaturePhil http://www.usefilm.com/photographer/31307.html >> I can't find a tire size on an F1 tire, but it looks low profile to me - >> a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 3 lines] >diameter of 660mm, with 355mm wide wheels at the front and 380mm wide >wheels at the back. The front tyre tread width may not exceed 270mm. HAAHAHHAHAAHAHHAAAHAHAHAHHHHAAAAAHAAHAHAHA ...hee [cough] >I'm >actually struggling to find the rule that sets the size of the rims, but >I thought they were 13". It must be in the regulations somewhere but for >some reason it's eluding me today. Signature"...Luigi follow only the Ferraris." >>> I can't find a tire size on an F1 tire, but it looks low profile to me - >>> a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 4 lines] > > HAAHAHHAHAAHAHHAAAHAHAHAHHHHAAAAAHAAHAHAHA ...hee [cough] I knew you'd like that one. SignaturePhil http://www.usefilm.com/photographer/31307.html >> I can't find a tire size on an F1 tire, but it looks low profile to me >> - a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 6 lines] > I thought they were 13". It must be in the regulations somewhere but for > some reason it's eluding me today. found the rules: http://www.fia.com/sport/Regulations/f1regs.html the max size allowed is a 460mm wide rear tire that can't be taller than 710mm. that size of a tire on various wheels: 13" - 460/40-13 14" - 460/38-14 15" - 460/35-15 16" - 460/33-16 17" - 460/30-17 so, even if they're running a 13" wheel, that's only a 40 aspect tire, which I believe is a low profile tire. Ray > >> I can't find a tire size on an F1 tire, but it looks low profile to me > >> - a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 9 lines] > found the rules: > http://www.fia.com/sport/Regulations/f1regs.html What the heck are the "exteme weather tyres" (as opposed to dry and wet weather tires). of which you potentially need 3 sets? Do they have F1 races during snowstorms or something? Would be fun to watch that "F1 gone rally" event :-] Note that they require homegenious compounds in all three types: no pumice impregnated center rib for Mikka Hakkinen! > the max size allowed is a 460mm wide rear tire that can't be taller than > 710mm. [quoted text clipped - 8 lines] > so, even if they're running a 13" wheel, that's only a 40 aspect tire, > which I believe is a low profile tire. That settles my grievance then. >> found the rules: >> http://www.fia.com/sport/Regulations/f1regs.html [quoted text clipped - 4 lines] > snowstorms or something? > Would be fun to watch that "F1 gone rally" event :-] Typically, dry weather tyres are used until the drivers are unable to get the power down or turn in, whichever becomes a problem first, then they change onto wet weather tyres (often termed "intermediates"). If there is significant standing water on the track, the intermediates will suffer from aquaplaning, and extreme weather tyres (often termed "full wets") are used. In 2007, the teams are limited to 14 sets of dry tyres, 4 sets of wets and 3 sets of extreme weather tyres per car per weekend. There are also limitations on the number of sets that can be used in the first two practice sessions. SignaturePhil http://www.usefilm.com/photographer/31307.html > >> I can't find a tire size on an F1 tire, but it looks low profile to me > >> - a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 9 lines] > found the rules: > http://www.fia.com/sport/Regulations/f1regs.html Thanks. Did you see the pictures of "extreme weather" F1 tires anywhere? Are they slicks or there is some grooves for water evacuation? I wonder how different they are from "wet weather tires". >>>> I can't find a tire size on an F1 tire, but it looks low profile to me >>>> - a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 13 lines] > Are they slicks or there is some grooves for water evacuation? > I wonder how different they are from "wet weather tires". no, but your comment about an F1 race in the snow made me chuckle. :) >no, but your comment about an F1 race in the snow made me chuckle. I wasn't in the country at the time and my memory is a bit hazy after all these years but sometime in the late 70's / early 80's an F1 car went out for a few exploratory laps around Brands Hatch when there was snow on the ground, possibly around April time if I recall. <scratches head> It might have been the aborted Race of Champions in 1982 or possibly a Gunnar Nilsson memorial. -- >>no, but your comment about an F1 race in the snow made me chuckle. > [quoted text clipped - 7 lines] > It might have been the aborted Race of Champions in 1982 or possibly a > Gunnar Nilsson memorial. I was at Montreal when it snowed the weekend of an F1 race. I'm not sure what year it was, perhaps 1980? Montreal can be odd even in June. Sometimes it's rained heavily at the hairpin while being dry as a bone at the opposite end of the circuit. >I was at Montreal when it snowed the weekend of an F1 race. I'm not sure what >year it was, perhaps 1980? > >Montreal can be odd even in June. Sometimes it's rained heavily at the hairpin >while being dry as a bone at the opposite end of the circuit. Just like Silverstone or Spa most years. I've been at a race during the summer either in the UK or Europe where there were hailstones an inch or more deep on the ground, again my intermittent memory doesn't recall where right now! -- I think it was 1979 >>I was at Montreal when it snowed the weekend of an F1 race. I'm not sure >>what [quoted text clipped - 10 lines] > > -- >I think it was 1979 >> [quoted text clipped - 10 lines] >> inch or more deep on the ground, again my intermittent memory doesn't >> recall where right now! Here's a treat. It's Google Video of the BBC coverage for the Montreal Grand Prix from 1985. Murray Walker / James Hunt 35 minutes of good fun with drivers of legendary time. http://video.google.ca/videoplay?docid=2527303899278312594&q=f1+1985 > > I think it was 1979 > >"Not Bernie Ecclestone" <nospam@nospam.com> wrote in message [quoted text clipped - 20 lines] > > http://video.google.ca/videoplay?docid=2527303899278312594&q=f1+1985 Lovely! Thanks for the link :-) SignaturePaul-B Formula 1 - cheat-free version coming soon. > > I think it was 1979 > >"Not Bernie Ecclestone" <nospam@nospam.com> wrote in message [quoted text clipped - 20 lines] > > http://video.google.ca/videoplay?docid=2527303899278312594&q=f1+1985 Great drive by Steve Johnson ( ;-), and I'd forgotten how casual F1 was in those days... marshalls wandering around, tables and umbrellas set-up outside the safety barrier, mayhem in the pits, and that lovely JPS Lotus livery. SignaturePaul-B Formula 1 - cheat-free version coming soon. >> > I think it was 1979 >> >"Not Bernie Ecclestone" <nospam@nospam.com> wrote in message [quoted text clipped - 25 lines] > set-up outside the safety barrier, mayhem in the pits, and that lovely > JPS Lotus livery. What's also cool is how there were almost no grandstands on the corner exiting the hairpin. We used to buy a general admission ticket for C$ 20, show up early, lay down a blanket and have the time of our lives! Now the entire place is packed with grandstands where seats cost 20 times as much, and general admission is a complete waste of time. > no, but your comment about an F1 race in the snow made me chuckle. > > :) A truly international race..... the Antarctic Gran Prix. Black tie attire required for all spectators ;=) > > I can't find a tire size on an F1 tire, but it looks low profile to me - > > a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 6 lines] > I thought they were 13". It must be in the regulations somewhere but for > some reason it's eluding me today. It's now about 14". From the 2008 rules: 12.4.4 Wheel bead diameter must lie between 354mm and 358mm. ** ** I downloaded the 2004 rules, and it was around 13" then: 12.4.4 Wheel bead diameter must lie between 328 and 332mm. > It's now about 14". From the 2008 rules: > [quoted text clipped - 5 lines] > > 12.4.4 Wheel bead diameter must lie between 328 and 332mm. Just as a clarification, About 14" is for 2008. The 2006 and 2007 rules on rim height (bead diameter) are the same as 2004. I didn't look up 2005, but I suspect it's the same. >> I can't find a tire size on an F1 tire, but it looks low profile to me - >> a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 6 lines] >I thought they were 13". It must be in the regulations somewhere but for >some reason it's eluding me today. IIRCC, the rim size is not regulated, just the diameter of the tyre, when fitted to the wheel. Since the width of the tyre dictates the ideal aspect ratio for the wall height, all of them would end up with roughly the same rim size. SignatureRegards, Frank >>> I can't find a tire size on an F1 tire, but it looks low profile to me - >>> a 355/30-15 has a sidewall almost the same height as a 205/50-15... [quoted text clipped - 10 lines] > ideal aspect ratio for the wall height, all of them would end up with > roughly the same rim size. If you read the whole thread you'll see that the bead diameter is regulated, and hence the diameter of the rim must be more or less the same as the bead diameter, give or take. SignaturePhil http://www.usefilm.com/photographer/31307.html >>>> I can't find a tire size on an F1 tire, but it looks low profile to >>>> me - a 355/30-15 has a sidewall almost the same height as a [quoted text clipped - 15 lines] > regulated, and hence the diameter of the rim must be more or less the > same as the bead diameter, give or take. If it's a 14" diameter wheel that the tire requires, you're going to have a hard time fitting any other wheel on that. I'm assuming the suppliers of tires have a list of possible sizes. Ray > for max performance summer tires I'd define it as "grips tenaciously > to the wet pavement at the temperatures above 45F" Hi, This is a "summer" tire? What kinda summer weather do you guys have where you are? Rick >>for max performance summer tires I'd define it as "grips tenaciously >>to the wet pavement at the temperatures above 45F" [quoted text clipped - 3 lines] > This is a "summer" tire? What kinda summer weather do you guys have > where you are? To be fair, I think the meaning is for the traditional "3-season tire" that is somewhat incorrectly refererred to as a "summer tire". > > All that alloy vs steel business got me thinking (plus a guy bitching > > on the ford newsgroup about the lack of 80 profile tires): [quoted text clipped - 12 lines] > the rubber is rock hard at room temperature so they don't come apart > under sustained high speeds. There are a whole lot of Z/W speed rated all-season tires that aren't exactly rock hard at typical spring temperatures. There seem to be a lot of things done to reduce temperatures at high speeds, like the stiffer sidewalls, nylon caps, and extra sidewall material. I'm sure some advances might allow a softer compound to hold up when it heats up. It might be a little squishy though. I'm pretty sure when you get to a Y speed rating, a harder compound is almost a necessity. |
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