What is factory wheel offset 67-72

[JP238]

I have searched google and the forum and can't find a definitive answer on the factory wheel offset for my year model truck.

I'm really wanting to put a newer factory style Chevy or GMC wheel on my 70 C10. Just trying to figure out how much different the offsets are. I'm pretty sure I would have to bore out the inside of the hub for the rim to even mount flush. Boring the hub isn't my concern, my concern would be the newer rim tucking too much inside and not being able to turn the wheel all the way..

[OARNGESI]

im pretty sure the factory rims were 15x7 with 3.5in bs
are you wanting to use factory99+ wheels if you have a 2wd the easiest way would to pick up some adaptors on ebay

[JP238]

I'm wanting the 2007+ Silverado 20's. I've heard about 50/50 on the spacers/adapters. Half say good, half say the wheels will break off and roll past you.

[pwdcougar]

How are you planning on boring out the hub? I have a set of 2005 era 16 inch 6 lug rims I'd like to run on my K 10.

[JP238]

From what I have gathered, you don't have to bore the whole hub out. You would just take a router and a router bit and slowly bore out the inside of the rim. I would think that would give you 1/4" to 1/2" play. Just remember if you do decide to do it (which I never have before), to use A LOT of oil and take your time.

Other than modifying the hub for the rim to sit flush, the only other thing I would be concerned with is the offset. This is where it gets gray for me. I can find the factory offset for the newer rims but not the older rims. The main concern being that the rims tuck too much to the inside.

[pwdcougar]

I'd like to get the late model aluminum rims to sit flush against the drums and have the center hole sit correctly on the hub. All my stock rims are on a truck a few towns away or I could measure. The truck has the original white steel rim for a spare and the 73 and up steel rally wheels.

The backspacing on these older rims has to be a lot less than the late model 90's era rims. I spent the last hour on ebay and searching this site trying to find if someone makes an adapter that will make up for the backspacing and allow for the different hub sizes.

[JP238]

The only truck I have found with the newer GM wheels is this one..

He has aftermarket spindles but not sure if they are C10 spindles or some other spindle to compensate for the offset.

[AzDon]

88 and later trucks and post-91 burbs use wheels that have deep backspacing and WILL NOT work on older trucks without spacers! 67-72 stock backspacing is basically 50% of the rim width and the rear-well clearance favors rims that are shallower on the back side to fit centered in the well. Modern stock GM is nogo!, but you can order your backspacing if you are buying new!

[LuckyScott]

I just dropped my sub, and I have steel rallye wheels are 15 x 8 with a 4 inch backspace. The back rims are fine, but the fronts are too far out. I got some new rims that are 15 x 7 with a 4 inch backspace so I know they will work on the inside. I just hope they are narrow enough. (I didnt want to got too skinney)

I need to move the tire inside the wheelwell just a little on the front.

[JP238]

Not sure what this trucks setup is but it looks fine to me. This is one of the first trucks I've seen with the newer style rims on it. So it can be done, just need to find out how.

[JP238]

Here's another pic

[pwdcougar]

It does look nice!

I was thinking of having a friend with a big lathe make me up steel spacers. He could machine in the different hub sizes. One set of holes would have a recess for lug nuts for the original hub, then have another set of studs put in with the late model threading. Steel would be pretty strong and they could be made up as thick as necessary to make up for the different backspacing too.

Paul