Subaru Forester Owners Forum banner

1 - 3 of 3 Posts

·
Registered
2004 Forester XT
Joined
·
372 Posts
Discussion Starter #1 (Edited)
Ok tire tech geeks...help me figure this out (or at least agree or disagree)... :icon_biggrin:

-------------------
Tire "A" is 235/50-17 has a section width of 9.5", and a tread width of 7.7"

Tire "B" is 215/55-17 has a section width of 8.9" and a tread width of 7.8" (and considering the measured rim width is 7", when mounted on a 7.5" rim, section width becomes ~9.1" according to a couple of the manufacturer's websites)

Both are mounted on a 7.5" rim.

Therefore, both tires would have the same approximate footprint (actual rubber to road), yet the 215 wide would end up with a straighter sidewall and 235 (with ~0.4" more of section width) would just be more "bulgy"?
-------------------

All of this is because I wanted to put 235/50-17 on my STi BBS's but it's quickly becoming a PITA (fitment wise on the rear strut). I wanted 235's to maximize my footprint with the 7.5" wheel. But if what I wrote above is correct, I may be able to get the same width of actual rubber hitting the pavement with a 215 as I would with 235, only difference being a straighter sidewall, which actually might give me a stiffer sidewall with more steering response and no strut rubbing? Can anyone just tell me I'm not crazy, or am I?
 

·
Registered
Joined
·
4,235 Posts
your thinking is right. The first number in the tire specs should be taken with a grain of salt; looking at the actual widths is what you want to do.

So, that "215" is actually a pretty beefy tire that should work well for what you are looking to do.
 

·
Registered
2004 Forester XT
Joined
·
372 Posts
Discussion Starter #3
your thinking is right. The first number in the tire specs should be taken with a grain of salt; looking at the actual widths is what you want to do.

So, that "215" is actually a pretty beefy tire that should work well for what you are looking to do.
Thanks! I just couldn't help but wonder if I was overlooking something. I've always taken the listed section width (as in 215 or 235) as cut and dry with only slight variation. I've never had to work with something this tight where a mere couple of mm made all the difference. Too bad selection is better for performance tires in 235/50 vs. 215/55, but I'll find something. :icon_biggrin:
 
1 - 3 of 3 Posts
Top