turbotater1

i am putting a set of 28" rear tires on a 2001 camaro and when i do i get an ABS error .
Is there a parameter in HP Tuners that lets me correct for a tire diameter difference front to rear?

mike

high n dry

iTrader: (18)

U'll have to get rid of abs all together... that's the only fix! HP tuners or any other software doesn't offer any type of abs "tuning"

rudytirerack

If you change the height from the front versus the rear to drastically the tires rotate at different speeds tricking your ABS system. I am not aware of any tuners that can fix this issue.

Firebrian

Just an ABS warning light/error is not so bad. If there's enough speed difference the system will activate the ABS and start buzzing and clicking. It would probably also kick in every time you slow the car down to under 10-15 mph...and you'd feel the pulses through the brake pedal. Those are the same symptoms you'd see with a cracked or damaged ABS tone/reluctor ring.

turbotater1

That sucks.
There is no symptoms currently other than the AB'S light on and not knowing if the system would work if needed.
Any idea how much difference in height you can have front to rear and be ok?

Firebrian

You can certainly test the car out with sandy or wet road skids and see if/how the ABS performs. The 28" diam tire is approx 9% greater in circumference than a stock BFG 25.7" 275/40/17 tire (2.3 in). Seems to me that 9% is quite a bit of wheel speed difference for the ABS. More than approx 1" difference might be too much (>5% or 1"). The ABS system gets confused and shuts down (warning light on). Only way to be sure is do some on-line research or go for a spirited test drive. There's also a small chance that one of the sensors was damaged during the tire install....but a 2" tire diameter differential is pretty big. On some cars that ABS warning might come in at around 50 mph. With a smaller difference, it might take a higher speed to bring it on. In doing a little reading 3/4" or even 1" can get you by. But some have reported issues at 1.5" difference. The system has to allow some tolerance for a mix of new vs. worn tires as well as differences in mfg sizing. One guy's 26" tire might be 1/2" difference from the other guy. To answer the orig question....something in the 3% to 5% range is about the limit.

HISS

iTrader: (52)

Pull the abs fuse, and pull the cluster and put a piece of black tape over the mil's that are illuminated. That way if you go back to smaller tires it's easy to reverse what you've done.

Firebrian

Any thoughts to whether one's insurance company would have an issue with the ABS being disabled (ie the policy is written for a standard car of that model year with operable safety systems - ABS, air bags, seat/shoulder belts, etc.).

01ssreda4

iTrader: (96)

If the light is on, the system is inoperable.