Need Tire Size Help 20" Wheels??
Thread Starter
Instructor
Joined: May 2008
Posts: 130
Likes: 0
From: deerfield beach florida
Need Tire Size Help 20" Wheels??
Bought 20" wheels for all around. yes should off went 19's in front but I have seen 20's before on c5's. and there a black rim and always look smaller then they appear. anyways have 8.5 wide in front and 10 wide in rear. I have the back figured out a 285/35/20. But looking for anyone running 20's or know anybody to get tire size that will fit in front? 245/35? or even a 255/35 or do i need a 30 or 25 series tire to fit? Thanks ahead of time for help.....
Tech Contributor
Joined: Oct 1999
Posts: 41,044
Likes: 9,808
From: Charlotte, NC (formerly Endicott, NY)
Because the front tire diameter has to be smaller than the rear diameter. If it is larger than the rear the EBCM thinks the rear tires are spinning and will apply the rear brakes and cut throttle. The EBCM compares wheel speeds at all 4 wheels to enact ABS and or TC.
This has been posted several times in the last few weeks as several newbies got surprised by this fact.
Bill
This has been posted several times in the last few weeks as several newbies got surprised by this fact.
Bill
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Traction control works by comparing front and rear wheel speeds. Altering tire diameter alters those read wheel speeds.
This simple answer is you must run a taller tire on the rear to keep traction control from intervening during normal driving.
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Brett Foote
Safety Car
Joined: Oct 2004
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From: Plano TX
I Have never understood why people put larger rims and tires on their cars without changing out the rear end gears.. The larger (diameter) the wheel and tire.. The slower the acceleration times..WTF?! Can someone please explain why people do this?? Is it for looks? It sure is not for performance... thanks sorry for my ignorance,.. just trying to understand the philosophy behind this concept
Last edited by David426; Aug 1, 2008 at 03:57 AM.
Uber Waxer
Joined: May 2004
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From: Hanover MD
Cruise-In 8-9-10-11 Veteran
CI 9, 10 & 11 Car Show Winner
St. Jude Donor '08-'10
I Have never understood why people put larger rims and tires on their cars without changing out the rear end gears.. The larger (diameter) the wheel and tire.. The slower the acceleration times..WTF?! Can someone please explain why people do this?? Is it for looks? It sure is not for performance... thanks sorry for my ignorance,.. just trying to understand the philosophy behind this concept
you are probably thinking 4wd trucks that get the huge tires and dont change gears to compensate.
I have 20's on the rear of my car and performance is certainly not lacking.
Drifting
Joined: Feb 2008
Posts: 1,765
Likes: 2
From: St. Clair Shores Mi
I Have never understood why people put larger rims and tires on their cars without changing out the rear end gears.. The larger (diameter) the wheel and tire.. The slower the acceleration times..WTF?! Can someone please explain why people do this?? Is it for looks? It sure is not for performance... thanks sorry for my ignorance,.. just trying to understand the philosophy behind this concept
if done correctly nothing really changes i.e.
if the tires are the overall tire diameter