[gripforce-mclaren]

I'd like to try different brand/size tires and I was wondering if it's OK to run non-stock size tires.

 

[360]

I'm about to order a set of Toyo R888 tires for track duty and I was wondering if it's OK to run non-stock size rear tires. The front tires have exact same size as stock P-zeros (235/35ZR-19) but the rear is 315/30ZR-20 vs stock 305/30ZR-20. Does anyone know if this will throw any codes or affect driving dynamics since it has slightly larger overall diameter?

Thanks,
Gregory

Surely it is only the tread width that is different ie 315 v 305, I would not have thought this would affect anything tires do not run that near he arches
Let us all know how they compare to stock tyres, talking to a test river at Castle Combe and he said if Michelin do a PS2 to fit he would try them over the Pirelli

 

[qvpower]

shouldnt be a problem. you are looking at a width difference of 10mm.

 

[texas mongrel]

Gregory
10mm wider section on a 30- series profile means that the radius of the tire will increase by less than one-eighth of an inch, i.e. Insignificant and not a problem. Your speedo will now be 3% slow tho'!

 

[gripforce-mclaren]

Gregory
10mm wider section on a 30- series profile means that the radius of the tire will increase by less than one-eighth of an inch, i.e. Insignificant and not a problem. Your speedo will now be 3% slow tho'!

Hope it's insignificant and won't cause any issues i.e. check engine light.
I can live with 3% slow speedo

 

[qvpower]

dont worry bout it... its already been fitted on there...

 

[gripforce-mclaren]

dont worry bout it... its already been fitted on there...

Great!!! In fact, I just ordered same HRE P44SC wheels in different finish.

 

[Mclaren-tech]

only time it would become an issue is if the speed difference between the front and rear wheels falls out side the parameters set up in the traction control system window. Steering angle input also has and effect on this calculation, but as long as everything stays within the pre-determined envelope you will be fine.

 

[texas mongrel]

When I bust my front tire at the track, we contemplated fitting a used 255/40 on the wheel to get me home (it was the only 19" tire available at the track) . However, we eventually decided that the big increase in diameter would screw up the computers and put me into limp mode; not good for the 100 mile drive home! Hence the ultimate decision to put on a truck. As an FYI for US guys, even tho' Tire Rack doesn't show any stock for the 12 c they actually have the tires and supply regularly to Dealers around the country. Via them, my new front was actually cheaper than tires for my Range Rover!

 

[qvpower]

only time it would become an issue is if the speed difference between the front and rear wheels falls out side the parameters set up in the traction control system window. Steering angle input also has and effect on this calculation, but as long as everything stays within the pre-determined envelope you will be fine.

So if you went with a 235/30/20 and 20" up on the front, which has an overall diameter of 25.55 vs factory 25.48, the speed down from 791 rev per mile factory to 789 rev per mile while retaining a 305/30r20 there would be little to no change. I guess it would only mean the window of that traction control parameter would only be if that speed difference exceeds beyond 5 revs per mile?

 

[Chrigel]

Surely it is only the tread width that is different ie 315 v 305, I would not have thought this would affect anything tires do not run that near he arches
Let us all know how they compare to stock tyres, talking to a test river at Castle Combe and he said if Michelin do a PS2 to fit he would try them over the Pirelli

so how did it go with the Toyo R888 315? I am getting them tomorrow.