ABS and Brake light after big tire install
 

I installed 305/45/18 on my 02 TA and the tires are 28in tall. As soon as I started to drive, the ABS light and the brake light kicked on. I checked the connectors on the back brakes where I put the tires on and they are still connected. Is there some issue with this?

its a common problem when stepping up to a tire that much larger than stock. I just swapped to a 28inch dragradial also and it set my abs and brake lights on the instrument cluster off. Im going to see if my tuner can't work something out when we tune the car this coming weekend.

How much of a difference can you get away with without tripping the ABS or traction control? I have traction control on my TA and I'm thinking about a 17/18 combo, but the overall sizes are going to off slightly. I'm thinking about 275/40-17 and 295/35/18.

I just realized it that it is caused by the front and back tires being different diameters. Is there any tuning option that fixes this?

Bump. Anyone?
Any idea what the tolerance is for difference in tire sizes front to rear?

theres really nothing you or the tuner can do. I took my gauge cluster out and covered the bulbs up so it wouldnt look like a christmas tree when Im driving. With my slicks and skinnies mine does the same thing, it also affects the abs working properly or at least did on mine.

I have the same problem ! i just switched to 325-50-15 NITTO's and the brake light came on .... I suppose thats why my cruize control dont work anymore ?????

believe you have to be within .5 of diameter between front and back tires

Pull the ABS fuse. Problem solved, easy to reverse.

I heard it was an inch.
I have 18 in front and 19 out back and the difference between the two tires is .8".

That's an inch in overall tire diameter?
Do you have traction control too or just ABS?

The problem you're seeing is common. You're ABS system is not calibrated for the tires you've chosen. There is no tuning software available for your situation. Our ABS delete kits cure braking issues and also allow for bias control with the adjustable proportioning valve.

Just deleting ABS isn't a workable solution to me for daily driving. It would be fine for temporary deletion at the track, but that's about it.

The question is how the ABS functions. If it operates based on a difference in speed between wheels, then the issue is just keeping non-stock wheels all close enough to the same diameter and what that allowable range is.

You can get rid of the light if that's what is bothering you. I don't really know if it affects the ABS or not when you do it though.

I'm interested in keeping both ABS and Traction Control fully operational. My question is how much that limits my tire choices. If I run the same size tires all around, even if they're non-stock, that "should" still work. There has to be some variance allowed just for going around corners. The question is how much variance in wheel speeds is allowed before it throws a code.

Example, I'm looking at a 17/18 combo with a 275/40-17 front tire. I have a few options for rear tires:
285/35-18 is 0.2" taller in overall diameter - 0.8% difference in wheel speed
295/35-18 is 0.4" taller, 1.8% difference in wheel speed.

I know the 275/40-17 & 295/35-18 combo is pretty common. Does everyone who runs this disable their ABS? How about Traction Control?

I may have to do this as a temporary fix when I get my new wheels/tires before I put the ABS delete kit on. So by taking out the fuse the car is good to go with no issues except for the light being on?

I run a 275/35/18 front, and a 275/40/18 rear, I have my Diablo programmer set to a tire size of 255/40/18. No abs lights/problem in my car.

you have about a 5% variance allowance on most cars. also depends on vehicle speed.

I have ABS and Traction Control

It was a .8" in diameter

Original Tires = 275/40/17
New Tires
Front = 255/35/18
Back = 285/30/19

No issues, besides the obvious light and the fact your ABS won't function.