Wheel offset calculations

[protonvx]

After much research, I came up with the following formula to figure out where the edge of the tire will sit in relationship to the outter edge of the front fender.

I am not sure if it matters much, but I took all my measurements on my Yukon with drop spindles and properly aligned.

I measured 4.25" from the front edge of the brake rotor to the outter edge of the front fender.

You can get the tire width from the manufacture's website. I used an app on on my Iphone to calculate the tire width.

All measurements are in inches.

(((tire width/2)-offset)-4.25)= distance either negative or positive in relation to the outter front fender edge.

Example:

305/40/22 Kumho is 12" wide
My 22x9.5 with a +45mm (1.77") offset

(((12/2)-1.77)-4.25)= -.02

So, my wheels/tires sit in .02".

Hope this helps!

 

[AZSCTACO]

Or you could use this calculator....

http://www.rimsntires.com/specs.jsp


Also your never going to get all 4 wheels/tires flush because the fronts always will stick out a bit farther then the backs because of the offset. The only way to do that is to get different offsets for the rears which will kind of defeat the option of rotating them.

 

[protonvx]

Unless I am missing something, that site does not show relationship of the wheel/tire to the fender which is what most people are concerned about. Mine is pretty dead on. But thank you for sharing the site.

From what I have read, from at least 88 on, gm trucks/suvs front wheel base is 1/2" wider per side than the back. Also the front end (body) tapers in some making the front track width appear wider than it is.

I am running hub-centric spacers in the rear with longer studs and ET style lug nuts. I can still rotate mine just fine. I also drive on crappy roads and haul a boat with no issues.

If one cared enough to get different offsets they would probably spend the money to have the tires remounted and balanced in order to rotate them.

Again, nice link, thanks!

---------- Post added at 11:20 AM ---------- Previous post was at 11:16 AM ----------

There are also several apps out there for the Iphone that are like the site AZSCTACO posted that are cheap or free.