Ive got some 17 inch c5 rims in the front and 18s in the back. My traction control kicks in at 60 like the car has no traction. I have to turn off the ASR in order for the gas pedal to work also, when I break hard the ABS brakes kick in. How do I fix this, I've got HPTuners and the speedo is set for the rear 18s.

Thanks

 

what are your tires like? i have the same set up as you and i do not have that problem.....im at a loss...anyone else?

 

my setup is the way it came from GM on the vettes 245s in the front 275s in the back

 

What is the full tire size spec (including aspect ratio)? With a 245/45-17 in the front and a 275/40-18 in the back you would have a diameter difference of about 1".

 

what does this mean? The difference of one inch, should I adjust the tire size to be between those two sizes?

 

That shouldn't cause problems with the traction control, but it might. Borrow a pair of stock diameter tires for the back and see if the problem goes away.

Are your tire sizes exactly the ones I assumed?

 

you guessed correctly. My car's ABS comes on even when the the car isnt slipping and once the car hts 60 the ASR comes on unless i have it turned off Help Please! I have HPTuners and I programed the new tire size for the rear tires, but should I calculate it to an average of the front and rear tires to prevent this problem from happening again?

 

Sounds like you may have a wheel sensor problem. The easiest way to rule out the discrepancy in front and rear tire sizes would be to try a set of stock diameter tires on the back. If the problem is still there, its not related to tire size.

I can't imagine why they would make the ABS and TCS sensitive to a 1" difference in tire diameter.... you can get differences that large when you mix and match brands in the same size, allow for new tread vs. bald, and allow for over- and under-inflation.

Have you ever had a "scan" done on the ABS/TCS computer?

 

Can I do the Scan with HPTuners? I dont think I have, but the car naver had this problem until I put the C5 wheels on and programing for the new diamater didnt help at all. I heard the TCS(ASR)/ABS system are separate and I cant program for them. Are new sensors epensive? Could I replace them just as a troubleshooting measure, or would that be too costly?

 

can anyone help? This is getting annoying!

 

Did you throw a set of stock size tires on there yet?

 

We've been trying to help, but you seem to be ignoring our suggestions. Try swapping the tires. Get it scanned by a technician with a Tech-2 scanner. I doubt that you can do it with HP Tuners.

 

99's have 4 channel, right?(sensors at the end of the axle tubes?) I know when I was swapping rears I cleaned up a LOT of shaving that were on the sensors by the reluctor rings. Could that have anything to do with it??

 

All years with TCS have the 4-channel system, with the reluctor wheels behind the axle hubs.