Anyone A Tire Expert?
Thread Starter
Instructor
Joined: Dec 2006
Posts: 155
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From: SJ CA
Anyone A Tire Expert?
I'm thinking of putting 285/35/18 on my stock 18x9.5 rear wheels and 255/40/17 on my stock 17x8.5 front wheels. I'm wondering if this setup will cause my active handling/abs systems to not work properly or cause any other problems? I perfer running the stock rims during the rainy season and would like a little more rubber on the road! I did a few calculations and came up with the stock rear tire size being roughly 0.98" taller than the stock front's height. The rear 285/35/18 size is roughly 0.82" taller than the height of the front 255/40/17 tires. What do you experts think? Will this work or should I just stick with the stock sizes? Oh yeah, one more thing; will more revolutions of either size tire mess up anything else besides speedometer readings or possibly even odometer readings?
Pro
Joined: Apr 2005
Posts: 651
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From: Littleton NC
From what I understand and everything I had read, you won't have any problems as long as the rear tire is larger than the front. I know I run 18's all the way around and I don't have any problems so I think you will be fine! 
Pro
Joined: Jul 2005
Posts: 569
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From: Nashville TN
This is commonly referred to as "Plus 0" sizing and will work just fine on your car. Do a search for Plus 0 or Plus zero sizing and you'll find lots of info. As far as your speedo, there's a linkthat shows the difference from the OEM tire, but that should only be 2-3% either way for what you're doing (i.e., speedo reads 60 MPH, you're actually doing 61.8 MPH). I just estimated those number, but this link will give you exactly what you are looking for. http://www.1010tire.com/TireSizeCalculator.asp
Race Director
Joined: Jan 2002
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From: I love you & miss you Linda
2017 C7 of the Year Finalist
St. Jude Contributor
Those tires will not cause any problems with the car and will work just fine. They ARE at the extreme limits of those wheels sizes but will be ok.
