... for quicker laps times.. 
Is tire width as important as we think it is?
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From: So.Cal.
Originally Posted by MadBill
Wow, some hot topic I just stumbled into!
There's definitely some good wheat amongst the chaff above, and the post by Knapp in the "Tire Width" link expertly covers the wide Vs. long contact patch issue (and explains why a tall tire/long patch is a plus for drag racing but not cornering), but there are a couple of other factors which have been omitted or touched only lightly upon:
o The classic F = N x mu friction applies to smooth hard surfaces and is only a part of a tire's grip.
o Mechanical interlocking ("hysteresis gearing") of the soft rubber with the track surface is a major factor.
o Molecular bonding of the tire to the track (think Post It Notes) is also significant, particularly on dry roads.
o The last two are temperature sensitive and a wider tire has more area to accept and dissipate heat, thus can be made softer without overheating.
o F1 uses tall sidewalls because they are limited to 15" wheel diameter. Prototype and Sports race cars generally use 18"-19" when rules permit.
o All else being equal, a wider tire will almost invariably corner faster, but may lap slower due to more inertia, higher rolling friction and or air drag.
There's definitely some good wheat amongst the chaff above, and the post by Knapp in the "Tire Width" link expertly covers the wide Vs. long contact patch issue (and explains why a tall tire/long patch is a plus for drag racing but not cornering), but there are a couple of other factors which have been omitted or touched only lightly upon:
o The classic F = N x mu friction applies to smooth hard surfaces and is only a part of a tire's grip.
o Mechanical interlocking ("hysteresis gearing") of the soft rubber with the track surface is a major factor.
o Molecular bonding of the tire to the track (think Post It Notes) is also significant, particularly on dry roads.
o The last two are temperature sensitive and a wider tire has more area to accept and dissipate heat, thus can be made softer without overheating.
o F1 uses tall sidewalls because they are limited to 15" wheel diameter. Prototype and Sports race cars generally use 18"-19" when rules permit.
o All else being equal, a wider tire will almost invariably corner faster, but may lap slower due to more inertia, higher rolling friction and or air drag.
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From: Ft. Lauderdale, FL, USA
When I first got my 436ci installed I still had my stock 275/40/17 Goodyear F1's on for a couple weeks. Could light them up from an 80mph roll. I put the 315's on and that speed went down to 40-50mph.
Wider = better traction.....fact.
From a dig too, a world of difference.
Simple.
1/4 mile drag race car, I have no idea. "Colonel" explained traction once before in a thread awhile ago, for 1/4 mile drag cars, and wider is not better.
Puttin 345/30/19 Hoosier R6's on the rear of my car when the new set-up gets done. We'll see what the RWHP limit is to hook on the street from a 50mph roll. And yes, it's getting a mini-tub to fit those big bitches.
.
Wider = better traction.....fact.
From a dig too, a world of difference.
Simple.
1/4 mile drag race car, I have no idea. "Colonel" explained traction once before in a thread awhile ago, for 1/4 mile drag cars, and wider is not better.
Puttin 345/30/19 Hoosier R6's on the rear of my car when the new set-up gets done. We'll see what the RWHP limit is to hook on the street from a 50mph roll. And yes, it's getting a mini-tub to fit those big bitches.
.
its not much of a comparo but i drove a C6 Zo6 and while my car felt faster i could feel the rear tires. i was crazy it felt like the rear was rolling on steam rollers. i could tell the rear tires were holding the road and grabbing traction way better than my 275s
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From: Dallas, North Mexico
I didn't read the whole thing, but it's not that simple. There is also F-sub-tire, for you engineering folk 
Simple physics is just that, simple. I'm fortunate enough to work in a field that is under high temperatures, pressures, velocities and thoroughly calculated. We account for everything. When you start factoring in everything, everything changes
Simple physics is just that, simple. I'm fortunate enough to work in a field that is under high temperatures, pressures, velocities and thoroughly calculated. We account for everything. When you start factoring in everything, everything changes
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This thread reminds me of old F1 and Indy pics of cars with tires that resembled modern day spare tire doughnuts. Apparently someone realized between now and then that racing goes beyond "simple" physics.
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From: Ft. Lauderdale, FL, USA
Originally Posted by treyZ28
I didn't read the whole thing, but it's not that simple. There is also F-sub-tire, for you engineering folk
Simple physics is just that, simple. I'm fortunate enough to work in a field that is under high temperatures, pressures, velocities and thoroughly calculated. We account for everything. When you start factoring in everything, everything changes
Simple physics is just that, simple. I'm fortunate enough to work in a field that is under high temperatures, pressures, velocities and thoroughly calculated. We account for everything. When you start factoring in everything, everything changes
So, it IS simple.
Wider tire = more/better traction....period. Street and strip.
1/4 mile drag racing.....11 second and slower
Wider tire = more/better traction.....period.
1/4 mile, faster than 11 seconds.
A wider tire starts to become weaker and a skinnier, properly matched tire starts to beat it. Depends on entire set-up and HP.
I'm not even in to drag racing and I know this.
.
Ive cut 1.8 60's on sumitomo 245 50 16 street tires, when i had my 4.11 gears
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
Last edited by 98TADRIVER; May 20, 2007 at 01:18 PM.
Just because a larger wheel and or tire doesn't spin as much as the smaller one did don't account it all to added width. More of the reason is because of the added wieght of the assembly being able to absorb the shift without over powering the grip. Again, width helps but it's not the only thing or the most significant.
Vernon
Vernon
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From: Dallas, North Mexico
Originally Posted by 98TADRIVER
Ive cut 1.8 60's on sumitomo 245 50 16 street tires, when i had my 4.11 gears
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
The rubber compound (sidewall and tread) along with tread pattern make a huge difference. Hop on a sport bike with shitty tires and then on one with good tires. As a matter of fact, I'd suggest a bike to anyone who wants to experience this stuff. Everything from powering through corners to chassis flex to the importance of good rubber.
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From: Dallas, North Mexico
Originally Posted by 98TADRIVER
Ive cut 1.8 60's on sumitomo 245 50 16 street tires, when i had my 4.11 gears
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
this might sound crazy to some, but when i went from 315 35 17 rubber on 17x11 ZR1s to stock T/A wheels with 245 50 16s, i hooked better. for a drag radial, i have MT ET street radials, 255 50 16 and hook like a **** on the street and track
The rubber compound (sidewall and tread) along with tread pattern make a huge difference. Hop on a sport bike with shitty tires and then on one with good tires. As a matter of fact, I'd suggest a bike to anyone who wants to experience this stuff. Everything from powering through corners to chassis flex to the importance of good rubber.
Originally Posted by treyZ28
The rubber compound (sidewall and tread) along with tread pattern make a huge difference. Hop on a sport bike with shitty tires and then on one with good tires. As a matter of fact, I'd suggest a bike to anyone who wants to experience this stuff. Everything from powering through corners to chassis flex to the importance of good rubber.
yea.. but that can set you into a diffrent mindset too.. i can have you hop on a bike with a 160 tire... and then goto a bike with a 180 or 190.... and suddenly you think.. WOW, i turn a hell of alot better with that 160...
Originally Posted by mpe488
that would certainly be the conventional wisdom, but if you looked at the patch as a wider area supporting the same weight, then you could analyze a small fraction of the patch and solve for it's friction force by using the equation (like in solving an integral.) Now the friction force per square unit will be smaller because the same weight is being applied to a greater area, but obviously there will be more square units of contact patch because the tire is wider.
In practice you should find that the total friction force:
(friction force per square unit) * (square units of surface area)
should come out equal in both cases.
In practice you should find that the total friction force:
(friction force per square unit) * (square units of surface area)
should come out equal in both cases.
a bigger "footprint" is always better in driving the vehicle
in our evasive driving course, the main focus surrounded not using brakes so much to be able to keep the four tires even on the pavement and have an equal amount of contact
compound does also make a huge difference, doing over 100 with firestones the tires begin to wobble and warp, leaving at times a smaller footprint and worse handling....
however doing speeds or higher with goodyears and pirelleis theres a huge difference....
these have all been in my patrol car and im not sure of the exact types of tires, just the brands because i never really looked, but i could tell a huge difference in handling and speed with the different types of tires, i do know that the firestones have a higher tendancy to feather up/get skinnier, then the other two brands....leaving a bad footprint....im glad we switched to the goodyears
in our evasive driving course, the main focus surrounded not using brakes so much to be able to keep the four tires even on the pavement and have an equal amount of contact
compound does also make a huge difference, doing over 100 with firestones the tires begin to wobble and warp, leaving at times a smaller footprint and worse handling....
however doing speeds or higher with goodyears and pirelleis theres a huge difference....
these have all been in my patrol car and im not sure of the exact types of tires, just the brands because i never really looked, but i could tell a huge difference in handling and speed with the different types of tires, i do know that the firestones have a higher tendancy to feather up/get skinnier, then the other two brands....leaving a bad footprint....im glad we switched to the goodyears
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Like I always say...college kids are dumb...this section should be renamed to 90% 1st year engineering students and 10% ppl who know wtf they're talking about tech...Do you honestly think your 3 variable equation in physics I can be applied here? Wait till you get out of college and get some real and practical knowledge and sense before you try and solve this with math.