Why my Traction Control System goes crazy
 

I have installed some 18" rims and new tires on my 350Z the overall diameter is now 1" smaller than the stock 17" and tires. So how can I fix my Traction Control problem from thinking my tires are losing grip when its not really losing grip at all? making my TCS light flicker and lose power even at 15 miles an hour around a corner.

I suspect your tire sizes are the problem. What sizes are the new tires?

Fronts are 245/40ZR18
Rears are 275/35ZR18

how would someone fix this problem?

Put 40 or 35 series on back and front

You saying keep all 4 tires 40 series or 35 series and that would fix the problem?

You need 275/40 on the rear. Read this... https://my350z.com/forum/showthread....1&postcount=45

Items in bold are your problem. Need 245/35 front OR, and more preferably, a 275/40 rear and the problem will go away.

Current front = 25.7, stock front = 26.0
Current rear = 25.6, stock rear = 26.7

Front got a little shorter, rear got a lot shorter - this is the problem.

Thanks for all the input this really helped out a lot

I wonder why he thought all his tires were 1 inch shorter than stock.

I do not think this is a tire size problem. I think it is a new tire problem. New tires are slippery.

Is why I burn mine down to 50% before I even start driving on them.

I could think of another possible issue as well, but I'll let someone else dive into that.

275/35ZR18: Actual speed 100.0 MPH. Speedometer will read 104.3 MPH. This will NOT cause SLIP but it is a significant difference.

It will cause a slip, his rear tire is shorter than the front.

I had to re-read David's post a few times myself. Maybe he hit the Vicodin before posting that up, as that is an unusual slip for him.

Yes my speedometer is off a little bit due to the fact that my tire size is different than stock but not enough to make a difference, also i seriously doubt my tires are losing traction at 15 miles an hour if so i need to get rid of the tires. I'm assuming and am pretty sure the fact that my fronts are now overall bigger than my rears even by just a few specs it will leave my car thinking im losing traction on the rear tires when really there just spining faster due to them being smaller than the fronts....


if your burning %50 of your tire off its your money not mine go ahead but as far as i know tires dont need all that

as for me thinking about my tires being 1" smaller than stock is because they are, after going bigger rims and smaller tires they measured out to be 1" smaller in diameter overall

What is the old tire size? What is the new tire size? Need all three numbers - for example, 245/45/18

old size was:
235/50/17
255/50/17

new size is:
245/40ZR18
275/35ZR18

Only the rear tire is shorter that stock, if you had a 245/35-18 front tire on it you would be fine. The problem is your tire height, revove the rear tires, and install 275/40-18's and save the 275/35-18's for front tires.

How did this work out? Did you get new tires or did TCS fix itself.