pros / cons of "stretching" thin tyres onto fat rims?
05-21-08, 04:38 PM
#26
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To be fair, that's jumping in a rally, which puts insane stresses on wheels that wouldn't be replicated on the street or on the track. There's a reason why wheels designed for rally use are heavy, they have to be to withstand the stresses.
05-22-08, 12:32 AM
#27
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You can get cheap, light, and strong with enkei. The rpm2 is a hella strong wheel thats about the same weight and price as the fno1rc. My friend hit a curb at 50-60mph and launched the car ~6ft up and landed on top of a hill. The slightly dented wheel held air. He broke everything else, caliper bracket, control arm, brake rotor, etc.
In front of the wheel is the hub area of the rotor that is still behind the wheel
In front of the wheel is the hub area of the rotor that is still behind the wheel
05-22-08, 01:32 AM
#28
They're about 14lbs for a 15x8, and are the ONLY ones I've found that will fit an FC in that size that aren't heavy steel wheels, drag wheels that can't handle cornering, heavy chrome muscle car wheels, or super expensive custom wheels ($550 shipped for Rotas vs. $2k+ for custom wheels).
How heavy are your wheels?
While the whole light, strong, cheap, pick any two thing is true in the extremes, there is some middle ground to be had, and then there's the RPF1's, which are strong, reasonably priced, and are in fact lighter (often significantly lighter) than most of the traditionally drooled over Volks, Gram Lights, SSR's, etc. Then there's things like the 5Zigen FN01R's which are a bit cheaper, only a bit heavier and still strong.
How heavy are your wheels?
While the whole light, strong, cheap, pick any two thing is true in the extremes, there is some middle ground to be had, and then there's the RPF1's, which are strong, reasonably priced, and are in fact lighter (often significantly lighter) than most of the traditionally drooled over Volks, Gram Lights, SSR's, etc. Then there's things like the 5Zigen FN01R's which are a bit cheaper, only a bit heavier and still strong.
17x9
17 lbs
05-22-08, 09:17 AM
#29
You can get cheap, light, and strong with enkei. The rpm2 is a hella strong wheel thats about the same weight and price as the fno1rc. My friend hit a curb at 50-60mph and launched the car ~6ft up and landed on top of a hill. The slightly dented wheel held air. He broke everything else, caliper bracket, control arm, brake rotor, etc.
05-23-08, 12:37 AM
#32
you know, i totally disagree with what the "OEM" setup is. its too skinny, too tall ratio, and generally looks like total ***. i dont disagree with strech, but too often people get carried away. but, im also not against HUGE WIDE tires, if you are putting down the HP, then strech dont ******* cut it. you need as much rubber on the road as possible. it gets to the point where rolling resistance doesnt matter as much as traction.
oh, and how are enkei rpf-1's cheap? theyre light and ******* strong. but DEFF not cheap. i guess a better wheel for the price, and better than 4000$ for volk anything of that size.
thing is about stretched tires is oppinion. guys that roll HUGE WIDE tires dont do touge or anything that calls for a ton of side to side quick turns. no, they are straight line minded. they go for something like 295/40/18. something that is still stiff, but has enough give for the high hp launches.
on the other hand, you have guys like us that have relatively low hp that use the cars and rely on the lower profile for the lateral movement of the car and cant have the sidewall flex that the muscle car guys can deal with.
Lloyd
oh, and how are enkei rpf-1's cheap? theyre light and ******* strong. but DEFF not cheap. i guess a better wheel for the price, and better than 4000$ for volk anything of that size.
thing is about stretched tires is oppinion. guys that roll HUGE WIDE tires dont do touge or anything that calls for a ton of side to side quick turns. no, they are straight line minded. they go for something like 295/40/18. something that is still stiff, but has enough give for the high hp launches.
on the other hand, you have guys like us that have relatively low hp that use the cars and rely on the lower profile for the lateral movement of the car and cant have the sidewall flex that the muscle car guys can deal with.
Lloyd
05-23-08, 01:07 AM
#33
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They're about 14lbs for a 15x8, and are the ONLY ones I've found that will fit an FC in that size that aren't heavy steel wheels, drag wheels that can't handle cornering, heavy chrome muscle car wheels, or super expensive custom wheels ($550 shipped for Rotas vs. $2k+ for custom wheels).
How heavy are your wheels?
How heavy are your wheels?
plus my tires are lighter than yours since they have much less sidewall (I run 235/30 in front an 255/35 in back).
and I paid $1200 for the set of 4 wheels. probably not as cheap as your rota's, but mine look better, are really ******* light(for the size), and much bigger so I can put much bigger tire on them.
tell me you'd still get the 15x8 just based on performance.
05-23-08, 01:11 AM
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05-23-08, 05:47 PM
#35
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I typed up a big long reply earlier, but it seems to have gotten lost, so here's the cliff notes version.
No RPF1's aren't "cheap", but compared to what you'd have to spend to get comperable wheels, they're an absolute bargain, and even going with cheap wheels you won't be able to save that much.
Yes I still would use the 15x8's as my track wheels, because performance and price are really the only criteria that matter, and the 15's win hands down in both. Besides, I think your wheels look rediculous, they're still heavier, lip is weaker than a more traditional rim profile, and they're more expensive.
No, the 18" tires AREN'T lighter, I looked it up, and for something like a BFG g-Force Sport, the 15's are 23lbs and the 18's (that's a 235/40/18, right?) are 25lbs and 26lbs, which goes to show that for any given tire the 18's will be heavier (and I checked other tires to confirm). This is due to the smaller diameter of the 15" tires, which helps give better gearing, a lower CG for better handling and the moment of inertia will be significantly less for both the wheels and tires due to the lighter weight and the weight being closer to the hub. This all means that the car will accelerate, brake and corner better.
No RPF1's aren't "cheap", but compared to what you'd have to spend to get comperable wheels, they're an absolute bargain, and even going with cheap wheels you won't be able to save that much.
Yes I still would use the 15x8's as my track wheels, because performance and price are really the only criteria that matter, and the 15's win hands down in both. Besides, I think your wheels look rediculous, they're still heavier, lip is weaker than a more traditional rim profile, and they're more expensive.
No, the 18" tires AREN'T lighter, I looked it up, and for something like a BFG g-Force Sport, the 15's are 23lbs and the 18's (that's a 235/40/18, right?) are 25lbs and 26lbs, which goes to show that for any given tire the 18's will be heavier (and I checked other tires to confirm). This is due to the smaller diameter of the 15" tires, which helps give better gearing, a lower CG for better handling and the moment of inertia will be significantly less for both the wheels and tires due to the lighter weight and the weight being closer to the hub. This all means that the car will accelerate, brake and corner better.
05-23-08, 06:34 PM
#36
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Of course you are going to pay more for that security, but well worth it when your life is on the line at high speed.
Majik,
In my E36 M3 (235rwhp in that state of tune) I could notice a SIGNIFICANT difference in how the car felt with my forged BBS RGR wheels and lighter tires, vs. my stock forged motorsport wheels and much heavier tires. In total it was a difference of almost 15lbs a corner, but only a difference of about 6lbs per wheel. Some R-comp tires are HEAVY! I used the RGR on the street with Goodyear F1 GSD3...which was a pretty light tire if I remember correctly.
That's my experience...
Original Poster:
Run the size tire, that the rim was designed for...and vice versa... Seems strange to do differently, but to each their own.
05-23-08, 10:56 PM
#38
05-23-08, 11:24 PM
#39
Majik,
In my E36 M3 (235rwhp in that state of tune) I could notice a SIGNIFICANT difference in how the car felt with my forged BBS RGR wheels and lighter tires, vs. my stock forged motorsport wheels and much heavier tires. In total it was a difference of almost 15lbs a corner, but only a difference of about 6lbs per wheel. Some R-comp tires are HEAVY! I used the RGR on the street with Goodyear F1 GSD3...which was a pretty light tire if I remember correctly.
That's my experience...
In my E36 M3 (235rwhp in that state of tune) I could notice a SIGNIFICANT difference in how the car felt with my forged BBS RGR wheels and lighter tires, vs. my stock forged motorsport wheels and much heavier tires. In total it was a difference of almost 15lbs a corner, but only a difference of about 6lbs per wheel. Some R-comp tires are HEAVY! I used the RGR on the street with Goodyear F1 GSD3...which was a pretty light tire if I remember correctly.
That's my experience...
I'm not saying lightweight wheels show no difference. But I am saying that the difference is only realized in certain applications. People need to pick the proper wheel for the proper application.
If someone said they wanted to run some boat anchors on the street, I would say go for it. There is nothing they should be doing on public streets anyway for heavy rims to matter. However, they said they were looking to gain performance for AutoX, my response would be different.
Gist of the point: Pick the right wheels for the right application.
05-24-08, 02:13 PM
#40
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I
Yes I still would use the 15x8's as my track wheels, because performance and price are really the only criteria that matter, and the 15's win hands down in both. Besides, I think your wheels look rediculous, they're still heavier, lip is weaker than a more traditional rim profile, and they're more expensive.
No, the 18" tires AREN'T lighter, I looked it up, and for something like a BFG g-Force Sport, the 15's are 23lbs and the 18's (that's a 235/40/18, right?) are 25lbs and 26lbs, which goes to show that for any given tire the 18's will be heavier (and I checked other tires to confirm). This is due to the smaller diameter of the 15" tires, which helps give better gearing, a lower CG for better handling and the moment of inertia will be significantly less for both the wheels and tires due to the lighter weight and the weight being closer to the hub. This all means that the car will accelerate, brake and corner better.
Yes I still would use the 15x8's as my track wheels, because performance and price are really the only criteria that matter, and the 15's win hands down in both. Besides, I think your wheels look rediculous, they're still heavier, lip is weaker than a more traditional rim profile, and they're more expensive.
No, the 18" tires AREN'T lighter, I looked it up, and for something like a BFG g-Force Sport, the 15's are 23lbs and the 18's (that's a 235/40/18, right?) are 25lbs and 26lbs, which goes to show that for any given tire the 18's will be heavier (and I checked other tires to confirm). This is due to the smaller diameter of the 15" tires, which helps give better gearing, a lower CG for better handling and the moment of inertia will be significantly less for both the wheels and tires due to the lighter weight and the weight being closer to the hub. This all means that the car will accelerate, brake and corner better.
ok....
sure, the 255's in the back are going to be a little heavier, but the much wider tire is going to offer a lot more grip. and with 350whp, the extra grip of a 255 vs. a 225 is going to help a lot more with acceleration than the maybe 6 pounds you're saving with your 15x8's.
plus, I always have the option of going with a much bigger tire, where as you're pretty much stuck with the size you have.
sure, you've got me beat on tire cost.
05-24-08, 02:44 PM
#41
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Like I said, these are my TRACK wheels, so why would I be running anything other than R's? (225/50/15 Hankook Z211 btw) Yes, there are wider 15's, you can get a 275/35/15 Hoosier for instance, but on an NA FC like I'm running, a 225 is probably the fastest tire width anyway, since anything wider will have increased rolling resistance which will slow you down on the straights, and I'm not exactly having problems with wheel spin now, so there's no need to go wider (I'd go stickier first anyway). Like I said before, my 15's are about 14lbs.
No, on the street I wouldn't be running 15's (and I don't, I've got 17's for that) and it's probably not the right setup for a turbo car (you'd want more tire and room for bigger brakes maybe), but that's not what I've been saying anyway.
I've NEVER said that there's one ideal setup that everyone should run or something like that, but for any given car there is one such setup.
No, on the street I wouldn't be running 15's (and I don't, I've got 17's for that) and it's probably not the right setup for a turbo car (you'd want more tire and room for bigger brakes maybe), but that's not what I've been saying anyway.
I've NEVER said that there's one ideal setup that everyone should run or something like that, but for any given car there is one such setup.
05-24-08, 03:20 PM
#42
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my 18x10 and 18x11.5, one of each combined weigh like 42pounds, wrapped in a box (I know this from shipping, lol). , so thats less than 21 pounds each.
plus my tires are lighter than yours since they have much less sidewall (I run 235/30 in front an 255/35 in back).
and I paid $1200 for the set of 4 wheels. probably not as cheap as your rota's, but mine look better, are really ******* light(for the size), and much bigger so I can put much bigger tire on them.
tell me you'd still get the 15x8 just based on performance.
plus my tires are lighter than yours since they have much less sidewall (I run 235/30 in front an 255/35 in back).
and I paid $1200 for the set of 4 wheels. probably not as cheap as your rota's, but mine look better, are really ******* light(for the size), and much bigger so I can put much bigger tire on them.
tell me you'd still get the 15x8 just based on performance.
05-24-08, 04:56 PM
#43
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Figured I’d chime in on this conversation and provide an insiders’ understanding on the subject.
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
05-24-08, 06:47 PM
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05-25-08, 12:51 AM
#45
Figured I’d chime in on this conversation and provide an insiders’ understanding on the subject.
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
05-25-08, 01:01 AM
#46
Figured I’d chime in on this conversation and provide an insiders’ understanding on the subject.
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
When I was working for Michelin’s Motorsports and Business Development Group, we introduced the Pilot Sport Cup tire, primarily targeted at the Porsche weekend racer as an alternative to the Hoosier and Yoko products available at the time. The tire was designed to last up to 3 times the number of heat cycles as the Hoosier product, while only falling off the pace approx. 4 tenths of a second (actually faster than the Hoosier in races lasting longer than 20 min). That translated into a competitive tire that could last a full season of, say, PCA events – no need to lay down cash for 3 sets of tires for a season anymore.
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall. The stretching allowed the tires’ contact patch to maintain a more consistent profile during “track out” and “turn in” transitions. While the consistent footprint showed promise, the design also had other advantages.
The stiffer sidewall created a healthy increase in the overall spring rate per corner. The consequent reduction in actual spring rate via softer springs allowed the suspension to conform to the road surface better, and as most know, the more the suspension is actually in touch with the surface, the faster you’re gonna go.
The “stretch” design was born of observing the Boser Blick style that’s been around in Europe for quite some time-a style not unlike that of the drifting community in Japan where a narrower than normal tire would be fitted on a wider wheel enhancing overall performance. Michelin has an extensive track record when it comes to unorthodox visions-just google “twheel”, or “tweel” and you’ll see what I mean!
Another important point when referring to manufacturers’ suggested sizes is that one must remember who the tire manufactures are catering to with their products. Most look at COMFORT and HIGH MILEAGE (or at least higher than the competitor), overall grip is a bit lower down the marketing research list.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing. The shoulder connects the contact patch and the sidewall and happens to be the hottest area on the tire! As an example, take a paper clip and bend it into a 90 degree angle-now start bending that paper clip back and forth from the ends. You will notice that the bend heats up rather quickly then eventually breaks. This is the same phenomenon that a tire goes though on a daily basis. Even R-Compound tires have that comfort factor designed into them because the tire manufacturers know that most r-compound buyers keep their R’s on even after their event and drive the car to and from work!
I’m of the belief that you can go too far in either direction. Both extremes have consequences that can be a detriment to performance, although some stretch, with proper spring rate correction can be a good thing. I know I’ve written a bit, but I’m thinking it’s better some manufacturer knowledge gets on these boards than to let bad information seed itself within the forum. Thanks
~Mike
gotta love it when someone that actually knows their **** chimes in!
thanks a million.
:: HIGHFIVE!! ::
Lloyd
05-25-08, 08:19 AM
#48
The tires’ design utilized a new construction that incorporated a trapezoidal profile that “stretches” the tires’ sidewall.
If a manufacturer could make all of their tires have a stretched design and still provide a high comfort level, they would as this would keep the tire’s shoulder from flexing.
05-25-08, 12:59 PM
#49
Lives on the Forum
Also, its pretty clear to me that he's saying that it's beneficial only to a point, and that like everything, while some may be good, more is not always better. This is where the drifters don't seem to get it.
I would add to the point about comfort being designed into R's in that it would only be true for certain R's, basically those with tread that are used OE on some cars such as the Michelin Pilot Sport Cup, Pirelli P Zero Corsas, and Yokohama A048R, whereas virtually slick tires like the BFG R1, Hoosier R6, Kumho V710, Hankook Z214 and such would have been designed purely for racing.
I would add to the point about comfort being designed into R's in that it would only be true for certain R's, basically those with tread that are used OE on some cars such as the Michelin Pilot Sport Cup, Pirelli P Zero Corsas, and Yokohama A048R, whereas virtually slick tires like the BFG R1, Hoosier R6, Kumho V710, Hankook Z214 and such would have been designed purely for racing.