370z Abs light with new tire size
 

This may be the wrong place to post this and I apologize first time using this. But I had a quick question with my current tire size fronts 235/45/18 and rears 265/45/18 I am getting brake and ABs lights. I understand that it is something to do with the wheel speed sensor. I am changing to a squared setup with 245/45/18 all the way around. This will solve the problem correct? And if anyone has the extra time to explain how the calculation work for figuring it out that would be cool.

The correct Sidewall Size for the 245 width 18 inchers is 40. so 245/40R18. Use the Link below to get the correct diameters for your setup. If your diameter measurements are outside of spec by a few percentage points, it will throw an error.

Tire Size Calculator

So this doesn’t make since to me because why would 245/40R18 be the correct size even tho 245/45R18 is the stock size tire for the rear wheels on the car. I also do not understand what tires have to be within the percentage. Am I only allowed to have a small percent difference between the size of the front and back tires. Or does it mean that the tires I run have to be in the percentage difference from what the stock tire size is programmed for? And if this is the case wouldn't it make it impossible to run squared wheels and tires?

To me it seems like 245/45R18 will work fine because it has less than a 1% difference between it and 235/50R18 which is the stock front tire size and is exactly the same as the stock rear tire size.

base model: 225/50R18 245/45R18 = 0.66%
sport model: 245/40R19 275/35R19 = 0.52%
nismo: 245/40R19 285/35R19 = 0.51%


abs/tc is kicked in when the front wheels are spinning at a difference speed than the rear. Has nothing to do with the relationship to the original wheel size afaik

my bad. i though it was a 40 sidewall. I dont have 18s.

The calculator should answer your questions regardless.