Rolling Circumference Tripping Out Abs/tc

[JimmyRickard]

Hi guys, I recently bought some new tyres for my FG F6 and they are tripping out the ABS & traction control, and also causing a brake failure signal. I took it to Ford Service and was told it was an issue with the size tyres I am using due to the rolling circumference messing with the computer, as they put a set of stockies on which worked fine.

I bought the car secondhand with staggered enkei wheels, which I believe are 19x11 in the rear and 19x8 (?) in the front. Not entirely sure what the size of the wheels are, but the tyres which the car came with were 275/30 in the rear and 245/35 in the front.

I got a set of 285/35's put on the rear as the 275's were stretched, which appears to have caused the issue as I haven't changed the fronts to match. Would putting 40 series tyres on the front fix the problem? I don't want to pay for another set of tyres and have the same issue. Is there a way to calculate this or something?

Cheers

[Sinista32]

Rear (285x35x19) RR is 341.05

Proposed front (245x40x19) RR will be 339.3

Difference is .5% - so should be within tolerances

Try this link http://www.brspecialtuning.co.uk/Tyre%20size%20calculator.htm

Edit: oh and use same type and brand of tyre.

Note also the 2nd number (40) is a percentage of the first number (245).

Edited June 26, 2014 by Sinista32

[JimmyRickard]

Thanks for that, will grab some new tyres and give it a go