I am looking to move up to 18's (18x10.5) this year and looking at the popular tire sizes it looks like 285-30-18's are pretty popular in most brands. However this presents a dilemma that the diameter of this setup is a full inch smaller than my old setup (275-40-17).

I already had some ground clearance issues on my old setup but this will be too much.

So did anyone else run into this issue? I am running Cusco coilovers so should I just adjust the ride height on them and then tune from there? There are a couple brands like the Hancook RS-3 that offers a 285-35-18 that would put me almost exactly the same diameter as before, however my rubber options are very limited at that point.

Or scrap the 18 idea? Go smaller rim width and run a 275-35-18?

Thanks for the input!

 

285/35/18 is not an oddball size. 275/35/18 will also work on a 10.5"-wide wheel.

 

We ran 285-30-18s in SCCA Touring 2 race trim. No particular problem with ground clearence, except when pulling it on and off the trailer. Since you have coilovers, it would probably be easier to just adjust them slightly.

 

As long as you can keep the alignment in check, go up a little in ride height. You can also go up in spring rate...assuming the dampers can handle it.