Taller Tires, will it effect the computer?
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Instructor
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From: Tampa Fl
Taller Tires, will it effect the computer?
I'm putting drag radials on my car for a track day this weekend. I have 295/35/18's on the car now and I'm going to put 305/45/18's on the car.
The 305/45/18's are 28'' tall as opposed to the 26'' 295/35/18's, will the computer get all screwy with the different diameter tire?
The 305/45/18's are 28'' tall as opposed to the 26'' 295/35/18's, will the computer get all screwy with the different diameter tire?
Race Director
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As long as the back tires are taller than the fronts, you'll be fine. The taller tire has less revolutions per mile than a shorter tire, and that's what the EBCM monitors through the speed sensors in each wheel. It compares front to back wheel speed, if it senses the backs spinning faster than the fronts, it will invoke traction control.
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Instructor
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From: Tampa Fl
Thanks for the reply back. I didn't even think about the traction control being an issue.
I was mainly referring to a thread I read earlier about "changing the rear gears", and had mentioned about the speedo calibration and the car going into "limp mode". Someone said that as long as the tires are the same size, there wouldn't be any problems.
Here's the Thread, under Post #4
http://forums.corvetteforum.com/show....php?t=1986164
I was mainly referring to a thread I read earlier about "changing the rear gears", and had mentioned about the speedo calibration and the car going into "limp mode". Someone said that as long as the tires are the same size, there wouldn't be any problems.
Here's the Thread, under Post #4
http://forums.corvetteforum.com/show....php?t=1986164
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If you go with more than a 2% variation from the assumed tire diameter in the PCM calibration, you can damage your powertrain.
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From: Ok! So you don't believe in conspiracies, but will you acknowledge the possibility of there being coordinated activities in secret places? Texas
Administrator
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Thread Starter
Instructor
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From: Tampa Fl
I'm getting the 305/45/18's brand new for free. It's only for the track.
What if I turn TC off? Shouldn't that fix the problem??
What if I turn TC off? Shouldn't that fix the problem??
Night Owl for life
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From: Bugs Bunny should'a made a left turn here
i'm not sure if a 305/45/18 28.8"OD tire would even fit back there without severly modifying the wheelwell.
i know a 335/30/20 with an OD of 28.0" needs wheelwell modifications.
http://forums.corvetteforum.com/show...2&postcount=43
Thread Starter
Instructor
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From: Tampa Fl
i run a 345/30/19 tire and it's very tall @ 27.4"OD .
i'm not sure if a 305/45/18 28.8"OD tire would even fit back there without severly modifying the wheelwell.
i know a 335/30/20 with an OD of 28.0" needs wheelwell modifications.
http://forums.corvetteforum.com/show...2&postcount=43
i'm not sure if a 305/45/18 28.8"OD tire would even fit back there without severly modifying the wheelwell.
i know a 335/30/20 with an OD of 28.0" needs wheelwell modifications.
http://forums.corvetteforum.com/show...2&postcount=43
Okay, thanks for that tidbit. I'm not modifying the wheelwell. I'll just see about having them exchanged for some Nitto 285/35/18's (25.91'' tall)or 305/35/18's (26.42" tall).
Thanks for your help.
Burning Brakes
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From: Columbia, SC
The most likely won't fit issue is primarily why I asked. To throw in my 2cents, if it's for the track, I'd go shorter to help your gearing. I run 315/30/18's which are an inch shorter than stock and about three feet wider than stock. On factory Z06 wheels, they work great.
Racer
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From: Dayton Ohio
Thread Starter
Instructor
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From: Tampa Fl
The most likely won't fit issue is primarily why I asked. To throw in my 2cents, if it's for the track, I'd go shorter to help your gearing. I run 315/30/18's which are an inch shorter than stock and about three feet wider than stock. On factory Z06 wheels, they work great.
I mounted them and balanced them this afternoon and they're on the car with the fatory 5 spokes for this Saturday's Track day.
Last edited by Hysteria; May 8, 2008 at 05:24 PM.
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Very funny. What I said is not a guess, its a fact. The Corvette was not designed with drag racing in mind and aside from the TC issue you can put undue stress on the rear axle by going with tires that are 2% taller than stock.
Drifting
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Uhh, No!
Now, how do 2% taller tires put extra stress on the rear axle?
Le Mans Master
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The tire will make a 10.2% difference in your speedometer reading. When your speedometer reads 60 mph you will actually be traveling at 66.1 mph. be careful if you drive to the track with them on.
Heres a web site that will calculate this information for you.
http://www.miata.net/garage/tirecalc.html
Heres a web site that will calculate this information for you.
http://www.miata.net/garage/tirecalc.html
Thread Starter
Instructor
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From: Tampa Fl
The tire will make a 10.2% difference in your speedometer reading. When your speedometer reads 60 mph you will actually be traveling at 66.1 mph. be careful if you drive to the track with them on.
Heres a web site that will calculate this information for you.
http://www.miata.net/garage/tirecalc.html
Heres a web site that will calculate this information for you.
http://www.miata.net/garage/tirecalc.html
