Title kind of says it all. I don't fully understand the + or - thing. I'm looking at a set of rims for the quad, and would like to know what I have now compared to what I'm looking at. What's the difference between offset, and backspacing?

The rims I'm looking at are 12" rims, the fronts are 7" wide with +4 offset with 4" backspacing, and the rears are 8" wide with -9 offset with 4" backspacing. Would these rims work, or would I be stressing the hub bearings too much?

 

I don't know what the stock measurements are, but you can take your wheel off and measure it pretty easily.

Using the rim's mounting surface as a reference point, measure toward the inside of the rim to where the plane of the inside bead is, and that will be your Offset "IN" measurement. Subtract that measurement from the rim's total width and you'll get the "OUT" value.

Basically, from where the rims mounting surface is, Offset "IN" and "OUT" is how many inches the rim extends INward toward the center of the ATV, and how many inches it extends OUTward. The total of the two values should equal the rim's total width.

For instance, a 7" rim could have a Offset of 4"IN and 3"OUT, or 5"IN and 2"OUT.
If you had an 8" rim with Offset of 4"IN and 4"OUT, the mounting point of the rim would be located at exactly the midpoint of the rim.

If your stock rear rim was 7" wide and had an Offset of 5"IN and 2"OUT, and you changed to an 8" wide rim with an Offset of 5"IN and 3"OUT, your new tire would stick out 1" more to the outside. If you changed to a 8" rim with 4"IN and 4" OUT, your new tire would stick out 2" more to the outside.

Whew!!!!!

I know that's probably more than what needed to be said, but that's how I understand it and it works for me.....LOL!

 

That's where I'm confused. I understand what you've said but if the rim is 8" wide how can it have a -9 offset? I guess the seller's info is wrong maybe?

 

Offset and Backspacing might not be interchangeable terms.

ADDED:

Check THIS thread for more info. [img]i/expressions/face-icon-small-smile.gif[/img]

 

The offset seems to be in millimeters. It can't possibly be inches. 4 mm is less than the diameter of a BB and shouldn't make any difference at all. -9 offset would mean it's only about 0.36" away from center. That would make sense. Just forget about the offset since it's so confusing and get the right backspace.

 

Typically offset is the differance in measurement between the flange where it meets the hub and the flange where it meets the rim. Its 8" wide the offset is 4" so teh flange mounts in the middle of the rim, and the offset could be 3" moving the rim 1" outword while keeping the support on the rim int he center. Easiest thing to think of is a Bud Wheel on the front of a Dually truck. It hasa negative offset to keep the load in the center of the tire and directly over the ball joint, even though the mounting flange is well outside the edge of the rim.

 

i belave its in inches like 4+3 would be 2" offset then a 3+4? i think. either way if you had a 3+4 and went to a 4+3 it would give you a 2" off set i beelave. correct me guys if im wrong.

 

I might have to take a picture today of my 500 and 800. The 500 has the stock 800 rims and the 800 has SS rims with less inside backspacing. The difference is noticeable.