clayton3854

gonna be ordering rims by end of the summer and wondering what the difference is between the 2 styles. thanks

s14unimog

offset is the distance measured from the center line of the wheel; in or out and is usually in mm (+ or -). Back spacing is the distance from the inside lip to the wheel mating surface and is usually in inches.


Here is a fun site to see the differences...
http://www.rimsntires.com/specs.jsp

ultimate-xj

They are the same thing just different ways of saying it

Hoooper

NO. Two wheels with 4" backspace but different widths will have the exact same distance from inside lip to WMS, but their offset will be different. Similarly, two different width wheels with the same offset will have different backspacing.

ultimate-xj

Yes you are correct I was saying that they mean the same thing it's just two ways of saying it. Like centimeters and inches, 1 in doesn't equal 1 mm but they both measure length. Both offset and backspacing measure where the mount surface is.

Pnguyen7

so you measure offset from center line of tire to the wheel hub surface that the wheel bolts to?

Pnguyen7

im tryng to find best 33/12.5/15 and wheel combo. i was thinking 15x8 with 4" BS someone said 3.75" with 15x8 and 33's but with 15x10, 4"BS if not that.
(which is what i got)

ultimate-xj

There is only 1/4" difference between the 15 x 8 so not a big difference. The 15 x 10 will make the tire look wider but that also means that you have a lot better chance of rubbing. The extra 2" of wheel will be on the outside of the rim, so it will stick out 2" farther than the 8's.
An

Pnguyen7

so i want my 15x10s kinfda i like the wider tire look.

clayton3854

so if you want the tire to stick out farther then it doesnt matter what you look for offset vs backspacing? they both do the same thing which is stick your tire out farther? just differnt measurements and different ways of saying it?

and 15x8 15x10 15x7? i thought that was all the size of the rim? not the width of the rim? have i been under the wrong impression this entire time?

Hoooper

Height x width is what you're looking at. Those wheels are 15" tall by 7" wide, 8" wide, and 10" wide. With the same offset, the 10" wheel will stick out further. But with less backspacing, they will all stick out further

Xjtim

I have 15x8 with 4" BS with 33x12.50x15 bfg ats...no rubbing at full lock at all. I'm at 4.5" and haven't trimmed the fenders, so I do rub, I didnt bumpstop correctly and the jeep gave it's tires a "custom" siping job lol....I wouldn't go with 3.75", it's more harsh on the wheel bearings, plus I think 4" is very stable, with or without the sway bar...I'm happy with mine. I think it has a nice stance too. 15x10 is too wide for a 12.50 tire IMO...15x8 will hold the bead down to like 5 psi or so...at 15x10 you'll have more of a chance to pop a bead.

Pnguyen7

yea i know but they were free so couldnt pass on them

Xjtim

Can't beat that! Lol

andecase

so i found this picture with where you measure from and all that jazz

it this correct from what you guys know? their calling the backspace "rear spacing"