Question about tire diameter?

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Apr 21, 2006 | 06:13 AM

LSs1Power

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Question about tire diameter?

Im running 315/35/17 tires now which should be around 25 or 26" right? Im running out of 4th gear in the traps.

My question is how much would a 28" tire help in this situation? How much faster can you go in 4th gear with a 28" tire compared to 25-26" at the end of the traps?

Thanks

Apr 21, 2006 | 09:41 AM

RaNsOm

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your tire is about a 26". what size gears do you have?

I use 4.33's and a rev limiter of 6700 and I have stuff enough RPM left using 27" tires.

Apr 21, 2006 | 11:26 AM

Anidote00

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A 28" would help out alot!! You could probably run at least another 8-10 mph if not more, with a 28" tire.

Apr 21, 2006 | 12:17 PM

T6Rocket

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Quote:

Originally Posted by LSs1Power

Im running 315/35/17 tires now which should be around 25 or 26" right?

It is 25.6", pretty small. 28" tires would be a big difference!

Al

Apr 21, 2006 | 02:44 PM

LSs1Power

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So a 28" tire should be good for around 136mph in traps with a 3.73 gear? My 25.6 tires got close to 6700RPM with a slipping clutch trapping 127mph. Thats when i had 548rwhp on the dynojet. Now i have 130-160rwhp more that before with a new clutch. If the 28" tire can give me up to 136mph that would be great.

Isnt there a way to calculate the speed possible with tire size and gearing?

Apr 21, 2006 | 04:34 PM

RaNsOm

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Quote:

Originally Posted by LSs1Power

www.f-body.org/gears

Apr 21, 2006 | 05:11 PM

LSs1Power

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Quote:

Originally Posted by RaNsOm

www.f-body.org/gears

Thanks for the link

I did the numbers there and it showed 13 mph more at 6700RPM running 28" tires instead of 25.6"

Im not really sure about the calculator though because it showed the 25.6 tire good for 137mph while i was close to my limiter which is around 7K RPM (I remember getting shift light on before i passed the traps and my shift light is set at 6300RPM) and only trapped 127mph.

I used these gearings numbers for the T-56, 2.66, 1.78, 1.3, 1.00, 0.74, 0.50