[dradernh]

Originally Posted by SerenVoX

Could you tell me if these tires will work with my new wheels?

Currently I have Staggered Setup:
Bridgestone RE-71R 235/40/18 FRONT 8.5
Bridgestone RE-71R 265/35/18 REAR 9.5

I'm switching to Square 8.5 on all 4 wheels. I know the front tires would work but will my rear tires fit? Will this be safe to run on the circuit track?

If the rear tires didn't fit, would it be better performance to run a 245/35/18 on all four 8.5s for the track?

I am XDRIVE if this matters. Ideally Id like to run my tires I already have. But I also want to know which size tire is most ideal for and xdrive on the track with my four 18in 8.5.

Thanks for any clarification on this!
Offsets and suspension is good.

8.5" wheels are not recommended for your rear tires; see the Rim Width Range below:



I assume you could still run it, but I have no idea how safe it would be. Autocrossers, including successful ones, often match tires and wheels well out of the norm, and it works for them. A circuit track is a much different challenge for a tire, though.

The general rule of thumb for matching tires to wheels when going to the track is that the tire's tread width be +/- 1" of the wheel width. In the case of the RE-71R, that puts the 245/40-18 in the sweet spot. Note that there is no 245/35-18 in RE-71R. Although I'd choose a 35-series over a 40-series for the track, I don't know how much difference it's going to make unless you're competing in time trials, autocross, or something like that. All else being equal, the tread compound trumps the series height.

A tire tread width on the minus side of the +/- 1" range will provide the driver with crisper handling (e.g., a tire with 8.1" of tread width on an 8.5" wide wheel will generally have better turn-in characteristics than a tire with 9.1" of tread width on that same wheel). That generalization is widely accepted by track rats who have often tried quite a few variations while looking for the best combination of grip and steering feel.

You too may well end up trying a number of combinations until you find one that you're satisfied with. Same thing with brake pads, tire compounds, and any other variables you choose to play around with (e.g., power, differentials, weight reductions, etc.).