Tyre width advice needed

[wiggy]

Gregor

the difference between front and back can screw up your ABS system if the difference is too much.

Std size wheel of 225/50/16 = 1983.60mm Calculated Rolling Circumference.

I have chosen 225/45/17 fronts = 1992.71mm (0.5% bigger)
I have chosen 255/40/17 rears  = 1997.42mm (0.7% bigger)

Giving only a 0.2% difference front to back

Both of these are within the tolerance allowed for ABS system to function correctly.

Also because of the slight difference in size my speedo will read slightly slow. going off the rears this is what I get.

Revolutions per Kilometre   old 504.1     new500.6
Revolutions per Mile                   old 811.3   new805.7

Fronts

Revolutions per Kilometre   old 504.1     new 501.8
Revolutions per Mile                   old 811.3     new 807.6

regards

[Shark]

hadn;t thought about ABS bud.

Surely the 255 235 combo is okay though as Mazda used it on some of the cars?

[wiggy]

235/45/17 are 1.2% bigger than 255/40/17 and will be fine as far as ABS goes.

I think your allowed about 4% difference before it might srew up the ABS sensors. You can go to a 45 profile on the rears and still get away with it at 2.7% difference.

Cheers