Tire height
Tire height What are the Advantages/Disadvantages of running a taller tire on the rear. I see races limited to certain size tires only and since my car came with 11in rear ZR1 rims I've always just ran different 315/35/17 drag radials. But what would somebody gain by changing from a 26in tire to a 29in tire? I've been looking at getting some 15" rims and would like to know before I start looking at 15s.
Based on engine HP and gearing.
More hp = more gear = taller tires.
i.e. on my car as a nitrous huffer -- N/A, 420rwhp, 4.30 gears, 30" tires work great went through the traps at 6700rpms. Same engine, same gears, same tires on 150 shot of nitrous (about 600rwhp), ran out of gear at 1000' mark - would have had to change out gears or taller tires (which is not an option)- BUT didn't get a chance as put it on the bumper and broke the engine.
Twin turbo (now): on 10lbs of boost the SS make about 880rwhp; had to drop to 3.50, with 30" tires. Trap about 6800rpm's.
See: more hp, either bigger tires or less gearing.
David
More hp = more gear = taller tires.
i.e. on my car as a nitrous huffer -- N/A, 420rwhp, 4.30 gears, 30" tires work great went through the traps at 6700rpms. Same engine, same gears, same tires on 150 shot of nitrous (about 600rwhp), ran out of gear at 1000' mark - would have had to change out gears or taller tires (which is not an option)- BUT didn't get a chance as put it on the bumper and broke the engine.
Twin turbo (now): on 10lbs of boost the SS make about 880rwhp; had to drop to 3.50, with 30" tires. Trap about 6800rpm's.
See: more hp, either bigger tires or less gearing.
David
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Joined: Oct 2007
Posts: 1,129
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From: Ventura County, California
Advantage: A taller tire with more sidewall has a larger contact patch and will absorb more of the initial hit with the sidewall which helps make it a little less prone to tire spin.
Disadvantage: Running a bigger tire than you need will slow the car down.
If you're thinking of going 15" with a drag radial I would maybe look at a 275 60 15, it will work with your gears and transmission well.
My friend has run 8.30's on that tire with an auto. Another guy I know runs an f-body thats been low 8's with an auto as well.
A 29" drag radial would be too much tire for your power levels now and would most likely make your car slower than if you used one of the smaller drag radials.
Disadvantage: Running a bigger tire than you need will slow the car down.
If you're thinking of going 15" with a drag radial I would maybe look at a 275 60 15, it will work with your gears and transmission well.
My friend has run 8.30's on that tire with an auto. Another guy I know runs an f-body thats been low 8's with an auto as well.
A 29" drag radial would be too much tire for your power levels now and would most likely make your car slower than if you used one of the smaller drag radials.
Last edited by chrismorales75; Oct 10, 2007 at 06:13 PM.
Based on engine HP and gearing.
More hp = more gear = taller tires.
i.e. on my car as a nitrous huffer -- N/A, 420rwhp, 4.30 gears, 30" tires work great went through the traps at 6700rpms. Same engine, same gears, same tires on 150 shot of nitrous (about 600rwhp), ran out of gear at 1000' mark - would have had to change out gears or taller tires (which is not an option)- BUT didn't get a chance as put it on the bumper and broke the engine.
Twin turbo (now): on 10lbs of boost the SS make about 880rwhp; had to drop to 3.50, with 30" tires. Trap about 6800rpm's.
See: more hp, either bigger tires or less gearing.
David
More hp = more gear = taller tires.
i.e. on my car as a nitrous huffer -- N/A, 420rwhp, 4.30 gears, 30" tires work great went through the traps at 6700rpms. Same engine, same gears, same tires on 150 shot of nitrous (about 600rwhp), ran out of gear at 1000' mark - would have had to change out gears or taller tires (which is not an option)- BUT didn't get a chance as put it on the bumper and broke the engine.
Twin turbo (now): on 10lbs of boost the SS make about 880rwhp; had to drop to 3.50, with 30" tires. Trap about 6800rpm's.
See: more hp, either bigger tires or less gearing.
David
315-35-17 have very little tire wall. Answer to your question is yes. the 315's are 25.5" tall x section width of 12.6 on 11" tires (their site doesn't say anything about the actual tread width).
With the stock rear-end, this would work IMO: 15x10 w/7" or 6.5" b/s. Run the M/T DR 275x50Rx15. The height is a little taller than the 315's, but only .5" (26.1 M/T vice 25.5 BFG's). The M/T tread width is 10.4. This "should" give the contact patch you need and let you finish in the 7000rpm range.
NOW, it would be a little different if say you change out your gears to a 4.10. Than go with the 275x60Rx15 -- almost the same but are 28" vice the 26" tall. -- more side wall with the 60's vice 50's.
Daily driver and very little drag: keep the 3.73.. Daily driver but multi-weekend drags: change to the 4.10.
David
With the stock rear-end, this would work IMO: 15x10 w/7" or 6.5" b/s. Run the M/T DR 275x50Rx15. The height is a little taller than the 315's, but only .5" (26.1 M/T vice 25.5 BFG's). The M/T tread width is 10.4. This "should" give the contact patch you need and let you finish in the 7000rpm range.
NOW, it would be a little different if say you change out your gears to a 4.10. Than go with the 275x60Rx15 -- almost the same but are 28" vice the 26" tall. -- more side wall with the 60's vice 50's.
Daily driver and very little drag: keep the 3.73.. Daily driver but multi-weekend drags: change to the 4.10.
David
TECH Fanatic
Joined: Oct 2007
Posts: 1,129
Likes: 0
From: Ventura County, California
A 275 60 15 is *NOT* 28" don't go by the tire company's measurements.
I have a 275 60 15 on my car and it is a hair over 27" tall.
The set of ET Fronts we run are 26" and actually measure 24.75"
Best way before you get any tire is measure it yourself.
A 315 tire will have a tread about 10.50" - 10.75" depending on the brand"
Also I would keep the 3.73's, a 4.10 is a weaker gear (the teeth are smaller) but will add performance in the 1/4, but not much for the price of new gears and getting them put in and as far as gas mileage the difference between 3.73 and 4.10 was not much at all.
I have run 3.42's 3.73's 4.10's and 4.56's in a f-body.
I personally liked the 4.10's all around.
And turbo, blown or nitrous cars can get away with less gear. A buddy of ours runs 3.08's, but then again he has a LOT of power.
I have a 275 60 15 on my car and it is a hair over 27" tall.
The set of ET Fronts we run are 26" and actually measure 24.75"
Best way before you get any tire is measure it yourself.
A 315 tire will have a tread about 10.50" - 10.75" depending on the brand"
Also I would keep the 3.73's, a 4.10 is a weaker gear (the teeth are smaller) but will add performance in the 1/4, but not much for the price of new gears and getting them put in and as far as gas mileage the difference between 3.73 and 4.10 was not much at all.
I have run 3.42's 3.73's 4.10's and 4.56's in a f-body.
I personally liked the 4.10's all around.
And turbo, blown or nitrous cars can get away with less gear. A buddy of ours runs 3.08's, but then again he has a LOT of power.
Last edited by chrismorales75; Oct 10, 2007 at 11:13 PM.
