coldfire

Just wondering from which points on the rim do you measure for the dimensions?

I know my rims are 15" (because of the tires R15) but when I measured from lip to lip it was 16" so I take it the official measurement is from the inside???

How 'bout the width?

oldcutlass

Inside lip to lip.

joe_padavano

As you have found, a 15" tire means that the diameter of the hole in the tire is 15". That means that you must measure the bead seating surfaces (for both diameter and width) on the wheel. The dimensions of the lip outside the bead seating surfaces is not standardized, and aluminum wheels typically have larger lips than steel wheels, so you cannot simply measure outside-to-outside.

coldfire

Cool thanks guys,

They've got tires on them right now so I can't measure exactly, but they're almost 8" on the outside... so minus the lips I'm gonna assume they're 15x7... and with snap-in center caps, I'd say I've got myself a set of SS-III's on my '70!

Follow up question -- the tires I'm currently running are 235/60-15 (front) & 255/60-15 (rear) and sometimes I think they look a bit too small. I was thinking of going up to 245 & 275 when I replace them... will the back ones suck in to a 7" wide rim?

oldcutlass

Yes, the P275-60's will work fine on 7" wide wheels.

joe_padavano

Well, I'm not sure about "fine". They will work, but the rule of thumb is that the wheel width should be within an inch of the section width. 275 mm is about 12". 10" or even 8" would be better. The only thing going for you is that the 275s have a relatively tall sidewall, so they will flex.

coldfire

So you'd be worried about these?



(In case it's not obvious -- not my car btw) but I love the look of the wheel/tire combo

I'd say he's running something wider than 7" but still, the tire looks sucked in more than an inch

oldcutlass

BFG recommends a rim width of 7.5 to 10. These are pic's of the Plymouth I used to have with P275's on a 7" rim. They looked really nice under there.