What offset do we need for 3rd gen wheels? Should it be positive or negative?

 

What width tire and wheel do you want to run>?

How much do you want the tire to stick out, or be even with body?

 

My backspacing will be between 4.5 and 5". I'm gonna run anywhere from a 36x15.5 to a 40x15.5 on a 10 or 11" wide wheel when I make up my mind.

I was just wondering about off sets for our trucks and caliper clearance on 20" wheels.

 

Factory offset is +41mm (or very close to that).

A 4.5" or 5" B.S. on a 10" or 11" wide wheel is going to have negative offset, which means they'll stick out a mile and require lots of lift.

 

If you're refering to how wheels shops generally generalize it... You want positive... At least in my application to run 35's.

 

40-41mm positive-- this won't change with wheel width (unlike BS).

On a very wide wheel, the BS number can get huge to maintain proper offset.

 

But proper offset varies with wheel width and tire size.

 

That's what I was thinking. I would try and keep my backspacing to 5.5"+ at a minimum. I think stock is like 6.25" or 6.5".....

 

I disagree. The offset is the distance from the hub flange to the wheel's centerline. If you make a wheel wider while preserving the offset, that means that you've split the additional width evenly between the inside and outside of the wheel. IN this case, backspacing will increase by half the added width, while offset is constant.

Changing offset will move the wheel in or out relative to the hub. This has implications for bearing alignment and such.

Of course, this assumes that "proper" offset means maintaining factory wheel/bearing geometry. If you mean something else by "proper" then this indeed could vary considerably.

For example, the factory geometry may not allow tire fitment of max size, in which case reducing offset might delay the CA rub associated with larger tires.

Factory 2nd gen 16X8 alloy wheels (01-02) are only +20mm on the offset, so try a set of those if yoy don't mind downgrading to a 16" wheel.

JH

 

Correct.

Correct.

My definition of proper offset is one which allows a full range of motion in steering and suspension without rubbing. The whole bearing thing doesn't matter to me. While its logical to assume a reduced offset can adversely affect bearing life the larger wheel and/or tire also affects longevity whether factory offset is maintained or not.

Bingo. There are other things that may rub, also. And an improper offset could limit tire size to something much less than maximum tire size.

Won't fit over the brakes.

 

Unruly,

Your intended backspacing of 4.5 to 5 sounds about right for a 36" tire to keep it from rubbing at full turn. Rubbing the control arms that is. But with that offset and a 10 inch wheel you'll have some serious fender rubbing issues. Sounds like you are planning a big lift as part of the deal. They will probably stick out about 2-3 inches.

John