Traction Control issue

[blacksnake]

I just had new tires installed on the rear this morning. Same size as the ones that I wore out (Pirelli 255-50's). On the way back to work the traction control starts kicking in when the car shifts from first to second. There is no loss of traction to cause this.
What have these idiots done to my car?

[ts-pa]

Did you have any other service done at the same time?
I don't know how a tire change would effect the Traction Control. Maybe there is an oil film on the tread surface that might cause this.

[cyclopsram]

Even though the tires are the same marked size, they may have enough diameter difference from OEM to set off the TC, or they could have damaged the TC senders when lifting or changing tires.... I bet they did not even hand torque the nuts to 100 lb/feet. Any chance they rotated the tires before they put on the new rears...and you wound up with the old rears on the front? Try starting with the tranny in 2 and when you get to speed put it back in drive... this will eliminate first gear for the single event. Slow driving in 2 in snow is like having 4wd. Less torque to break the tires loose.

[carterj]

I just posted the same problem on my 04 MM. I had the front tires and front rims put on the rear, until my new replacement tires arrive. I wonder if the rims are dedicated to the front or rear?

[Bluerauder]

I just posted the same problem on my 04 MM. I had the front tires and front rims put on the rear, until my new replacement tires arrive. I wonder if the rims are dedicated to the front or rear?
Rims are identical front and rear. It is the tire size that makes the difference. 235/50s on the front. 245/55s on the rears. Makes for a difference in tire height and circumference. Need to maintain that ratio to within 5% or less to avoid T/C issues.

[ts-pa]

Rims are identical front and rear. It is the tire size that makes the difference. 235/50s on the front. 245/55s on the rears. Makes for a difference in tire height and circumference. Need to maintain that ratio to within 5% or less to avoid T/C issues.

Good call Charlie!:up: I can't believe that I didn't think of that, DOH:(!

[ckadiddle]

I bet your new rears were mounted on the front.

[blacksnake]

Thanks for the matrix info Bluerauder. You've got a "probably not" beside the size I used as it relates to ABS/TC issues. I also saw the other thread by carterj.
Although not stock, the Pirelli 255/50's have been my rear tire of choice for 3 years. Why the car would suddenly have a problem with them is beyond me.

I assume the only fix is via programming? Any other ideas would be appreciated.

[Raudermaster]

That's odd. I was going to suggest it's because it's not a 55 like stock, but you said you've been using them for 3 years. That really is strange for them to act up now. Try disconnecting the battery for about 15 min and see what happens.

[Bluerauder]

Thanks for the matrix info Bluerauder. You've got a "probably not" beside the size I used as it relates to ABS/TC issues. I also saw the other thread by carterj.
Although not stock, the Pirelli 255/50's have been my rear tire of choice for 3 years. Why the car would suddenly have a problem with them is beyond me.

I assume the only fix is via programming? Any other ideas would be appreciated.
Breadfan gets credit for the Tire Matrix. He put in lots of research to come up with all of that info for the site. :up:

Best I can figure is the wear/size differential between new rears and old fronts. 3-4 millimeters of wear on the fronts could put you above a + 7.5% ratio on front/rear tire size difference. That may just be enough to push you outside the normal margin allowance. When you started with both new fronts and new rears, they were both wearing at about the same rate and the ratio of front to rear size was staying approximately the same. Getting new rears reset the game against those worn front tires. This is just speculation on my part.

Two questions --- 1) How much wear on your front tires? 2) How's your tire pressure on the fronts?