Hi, does anyone know what % tolerance there might be on rolling diameter (circumference) on staggered wheel sizes.

I have a 60nm vc in the oppliger box and supra read diff weir kit then quaife at up front.

I am thinking of trying 16x8 ET 32 on rear and 16x7 et25 n front. (205 45 16 front and 225 40 16 rear)

This comes off a comparison website (0.77% speedo error between wheels at 30mph)


1856mm vs 1842mm front to rear.



Diameter 590.9mm 586.4mm Circumference 1856.4mm 1842.2mm

0.77% Reading at 30mph 30mph 30.23mph Reading at 60mph 60mph 60.46mph Ride height gain 0mm -2.25mm Arch gap loss 0mm -2.25mm


Compared to your existing wheel, this new wheel will have an inner rim which is 19.7mm closer to the suspension strut. The outer rim will poke out 5.7mm more than before.

 

Bump up

 

Spoke to Bara today and he said limit of 1% would be ok...need to work out what tyres are available to allow this.


1856 vs 1842 is bang on 0.99%

 

What happens though when the rear tyres wear down compared to the fronts? Might be 4x4, but you still have a split ratio. Might be too much difference when the tyres are half worn.

 

I have no idea of the percentages Toby, but when I get time I'm going to be fitting 9.5's to the rear of my car with 8's at the front.

Pretty sure tyre sizes are 255/35 & 225/40

Could be wrong though as it's been a while