well 305/35 and 255/35 are too much difference

[bct10985]

Just put on a set of 20x10 rear and 20x8.5 wheels with 305/35 nitto 555r and 255/35 nitto 555 and got the service stabilitrac message. According to a tire size calculator they should of been within 5%. Will driving around like this hurt anything? So does this mean now i have no stabilitrac no traction control and no abs? Is there any way to dissable this maybe in a tune or something? Or am i screwed

[K32 Camaro]

I have 315/35 and 245/45 20's. No problems here. Are you sure that's the issue?

[bct10985]

The service stabilitrac came on as soon as i put them on and drove less than a mile

[AG454]

I recently went to the same size rims as you, P-zero's 305 in back, but kept stock size 245 in front. No issues. That's a .3" difference. You should not exceed .5" difference is what I was told. I think you are about 1.38" difference, way too much.

[Top Off]

The combo I looked at showed the 255/35/20 at 5.8.

[Nine Ball]

Guys, pay attention to the aspect ratio on those tire sizes. The second number in the size.

305/35-20 and 255/35-20

That 35 is a percentage number, known as "Aspect Ratio". It means the sidewall thickness is 35% of the tire width. On a wider tire, that makes the sidewall taller, too. From your example:

305mm x .35 = 106.75mm sidewall height
255mm x .35 = 89.25mm sidewall height

Total Tire Height is calculated by:

(2 x sidewall) x (0.039 to convert to inches) + wheel diameter inches

Your example:

(2 x 106.75) x (0.039) + 20 = 28.32 inches tall tire
(2 x 89.25) x (0.039) + 20 = 26.96 inches tall tire

Big difference. These two need to be within 0.5 inches of each other.

The correct sized front tire would have been 255/40-20, which is 28.0 inches tall.

Tony

[SSDan]

Originally Posted by K32 Camaro

I have 315/35 and 245/45 20's. No problems here.

That's because those two sizes are the same in tire height which is the stock 20 tire height of 28.7.