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      12-07-2012, 11:07 AM   #1
BmerMeUp's Avatar

Drives: Cinderella: 2008 E91 328xi
Join Date: Nov 2012
Location: Ontario

iTrader: (0)

Tire vs Rim Width Ranges - How do YOU pick?!

Hi. So I think I understand the concept of "stretching" a tire and the risks of putting a too-wide tire on a too-thin rim, but even the calculators I am reviewing give a rim width "Range" for a given tire ratio. Offsets are still an entirely different problem for me, I know what it means, but have NO idea how one would really look compared to another or how that affects my track?!

For example, 235/35/19 says it can go on a rim width of 8 - 9.5 in. That's sort of a big range! Many here have that and call it staggered! So which is it - 8 or 9.5? I found a reference which suggests for every 0.5" of rim width the same sized tire will change in height by 0.2" (Tire Rack Calculator doesn't confirm this however?) so that gives me some idea at least.

But I'm trying to understand how to pick a properly sized tire which isn't stretched, won't rub, and will just "look good," nice and flush with a vertical sidewall. I'm not big on the "mushroom" effect when the tire is too wide for the rim nor do I want (although on some it looks good) the "stretched" look when it's the other way. All I know is I need an 18" rim on a 2008 E91 328xi due to road conditions here - still on the fence for staggered vs. square, and this "rim width range" bit isn't helping!

Arg. Thoughts?
How do you decide what rim and tire widths you think you want and know will fit?
And shouldn't offset-to-flush be a fixed number for a given chassis, based on the width of the rim?

Or MAYBE... Maybe I should just call Gary when I'm ready and give him my Visa number and wait for something nice to arrive at my doorstep?? Ha.