Got my new set of US Wheel 15" 7"wide 4.5" backspace 6lugs with Kumho Mud tires on, but now have a question about the wheels.

 

Subaru factory wheel are perfectly flat where it mates with the drumface, but the us wheels have two ridges, one about 1/8 high just on the outside circumfrence of the hub section, and one about 1/16" on the inside, both protruding toward the drum (see diagram). So if you bolt up two of the lugs, then look through the other holes with no lugs , you see that the suface you bolt the lugs to has a 1/8 gap between the wheel and the drumface.

 

My concern is;when I go to torque the lugs, only a small part of the wheel will actually contact the hub, also, wouldn't it bend the wheel slightly at the proper torque. I was thinking I could make a circular shim out of flat stock, that would fit in the little vally (with holes drilled for the lugs), but if I don't need to, I would rather not.

 

Cross Section of wheel and drumface at one lug bolt (my best attempt anyway):

 

TRY TO IGNORE THE DOTS - ONLY WAY IT WOULD LET ME DRAW IT!

 

..wheel ..........................subaru

...hub ............................drumface (imagine perfectly flat vertically)

.....[ ...............................[

.....[............................... [

......) -large ridge 1/8" .......[

___[____________________[ -----> towards truck

. lug bolt///////////////////// [

.______/////////////////////._[

.....} -small ridge 1/16....... [

.....[............................... [

 

 

 

Anyone have experience with this? Appreciate any help!

I just got a simular set of rims, however i havent mounted mine yet.

 

I think that,,,,

If you look closer at the rim hole you will notice that it curves in causing a "valley" to run along the bolt pattern. Oridginaly this design was to alow the rims to be tightend up while not streching or damaging the threads on the stud. The steel rim would flex just a minute amount.

In contrast a aluminum aloy rim sits flat againt the hub and it doesn't "flex" that is why Aluminium Rims have to be torked (torqued) with a tork (torque) wrench , so the threads on the studs won't be streached (or damaged or even broken) by over tightening.

 

As long a the "bead" you speek of makes a good continious contact with the hub it should be fine

 

I used to work for a firestone dealer "tire and lube guy"

However i have been known to be wrong;)

Bump for intrest or correction:)

I run the same wheels on my hatch with the six lug conversion. It's not a problem at all. I believe the ridge is there to allow a little bit of space for the lip of the hubcap to sit between the wheel and the hub/drum. As long as you're using hubcaps you should be all set. Even if you don't have hubcaps I doubt that you would tweak the rims by torquing your lugnuts, but it's a good idea to have hubcaps anyway.