My specific question is: What is the smallest (ie, available in all season formulations) tire I can fit on the 9" wide wheels in the back of my '89 951 (stock tire size of 245/45/16)? But with that asked (and already getting some pointers from the kind folks in the 944 Turbo forum), being the sort who'd like to 'learn to fish,' is there a resource out there I could use to figure this out myself? Most of the tire 101 faqs I've found don't address this issue. http://www.1010tires.com/TireSizeCalculator.asp is a useful tire calculator, but it's pretty onerous to harvest allowable rim width data. And I don't like the answer it gives me - I want to believe I can use 225/50/16's on the 9" wide rear rims, so of course I'm looking for a second opinion . Is there a list of tire sizes with the width rim they can be safely run on somewhere? A simple formula I can bang into Excel? Or is this a tire-specific question, with answers differing a bit amongst tire models or brands?

Thanks

 

Adding a few notes to my own question:

Tirerack has spec pages that get close to answering my question, such as seen here http://www.tirerack.com/tires/Spec.j...irePageLocQty= And the answer to is there an all season tire that will fit on a 9" rim (per manf's recs) is no. Dangit all. Digging through the tire spec pages for other brands is really making me think I'm going to need to breakdown and get some narrower rims for the rear and garage the 9" wide rims. At least this thread , https://rennlist.com/forums/wheel-and-tire-forum/291556-205-wide-tire-on-a-9-rim.html , shows I could be thinking sillier things than a 225 on a 9" rim (gotta love the cringe-worthy pics in it).

 

I would recommend using the tire "specs" section of our website under any given tire to determine it's mfgr. recommended rim width. Some are +/- the average. try to keep OD as close to OE as possible. Proper width will be determined by year make model, and wheel width / offset.

Or you can always call me.