Hub adaptor question

[BuddyP]

First off, what is a good company/website to go to for hub adaptors. Secondly, what is backspacing on a wheel that has a 38mm offset?

I found a set of BMW 3 series aftermarket wheels I like, figured in order to make these work on a 1st gen a person could have hub adaptors made that bolt onto the hubs, then has studs mounted to it that have the 120mm bolt pattern to bolt the 3 series wheels on and also give me the proper offset.

Thoughts?

[nicks67camaro]

Check this out. You can play with what you have now and what you are interested in. I believe offset changes based on the width of the rim. A 38 mm offset on a 8 inch rim is 6 inch backspace.
Hope this helps

[bochnak]

Adapters:

http://www.skulte.com/index.php/cPath/21

Backspacing formula:

http://www.skulte.com/adapterfaq.html

[BuddyP]

Thanks guys, that helped a lot!

So here's the scoop, I'm looking at possibly getting a 18x8 with 20mm offset and a 19x9.5 with 20mm offset. If I do my calcs right I'm coming up with needing a 3/8" spacer up front (18x8 wheels) and 1/2" spacer in back (19x9.5 wheels). Does this sound right?

BTW... 1st gen camaro ('68), no tub.

[bochnak]

From the FAQ's on the link above:

Are slip-on wheel spacers safe?
Slip on wheel spacers are safe, as long as you limit them to 1/4" or less. As the wheel is moved further out, the bending load on the wheel stud increases. We don't recommend using slip-on wheel spacers greater than 1/4" thick. New heavy duty studs are recommended as well. Slip on wheel spacers are not the same as bolt-on wheel adapters.

Can you machine adapters thinner than 3/4"?
In order to have the proper strength for the lugnut and stud seats, the thinnest bolt-on adapters we'll machine is 3/4". Be advised that anything thinner than 1.25" will have the lugnuts sticking out past the face of the adapter, and requires cavity back rims where there are pockets in between the lugnut holes.

[Apogee]

bochnak, I know you're just quoting Skulte's website FAQ, but if a 1/4" loose spacer is "safe", does that mean that a slip-on C5/C6 rotor is unsafe at .300"? They're essentially the same thing. I'm not advocating loose wheel spacers of any thickness, just trying to get everyone to think a little before condemning them.

As for your offset specs, they essentially drop from 20mm (.797") to 10mm (.394") in the front with the addition of a 10mm (.394") spacer. Similarly, the rear offset becomes 8mm (.315") in the back with a 12mm (.472") spacer. This means that your front and rear backspacing become approximately 4-3/8" and 5-1/16" respectively. Sorry about jockeying between english and metric.

[1FstChevy]

bochnak, I know you're just quoting Skulte's website FAQ, but if a 1/4" loose spacer is "safe", does that mean that a slip-on C5/C6 rotor is unsafe at .300"? They're essentially the same thing. I'm not advocating loose wheel spacers of any thickness, just trying to get everyone to think a little before condemning them.

Well, at least in the instance of a 2nd Gen Camaro your actually replacing the OEM hub/brake rotor with a seperate hub and rotor and typically after market ARP studs, or something similar that has a longer length to it which still allows the wheels to be bolted on in the same position in relation to the rest of the car, and still allows the lugnuts to be fully engaged onto the studs.

The primary reason spacers beyond .25" & .50" aren't recommended by may people or companies is because they move a wheel out to a further point away from the car/hub than would otherwise be safe because the further out the weight and force of the wheel is, the more stress is on the studs, and a shorter amount of the threads on the OEM studs are able to be engaged by the lugnuts.

Hopefully that clarifies stuff a little....

BTW good work on finding www.skulte.com they are actually going to be making a set of wheel adapters for me as well to adapt another 5 lug bolt pattern, and have been very helpful with specs and info! I'd recommend them to anyone!

[bochnak]

bochnak, I know you're just quoting Skulte's website FAQ, but if a 1/4" loose spacer is "safe", does that mean that a slip-on C5/C6 rotor is unsafe at .300"? They're essentially the same thing. I'm not advocating loose wheel spacers of any thickness, just trying to get everyone to think a little before condemning them.

As for your offset specs, they essentially drop from 20mm (.797") to 10mm (.394") in the front with the addition of a 10mm (.394") spacer. Similarly, the rear offset becomes 8mm (.315") in the back with a 12mm (.472") spacer. This means that your front and rear backspacing become approximately 4-3/8" and 5-1/16" respectively. Sorry about jockeying between english and metric.

I was just stating that the min thickness of an adapter is 3/4", and the potential isses with spacers.

I have seen adapters cheaper on ebay and googling "wheel adapters". I guess the major thing to look for is conical lug seats, which center the adapter better than a counterbore.

[MonzaRacer]

now if you can find lugs that go through the wheels and the spacer and stop at about 1/8 in from the rotor face AND the holes in the spacers have holes same size as the lug body diameter I have had good luck running them even when dragracing.
Also you should remeber to lube the studs with silver (nickle based) antiseize(as it doesnt promote over torqueing but does allow for a more uniform torque application.
I also like to make sure I use quality lugnuts that are fully threaded such as McGuards.
!/2 in studs should also be torqued (grade 8 actual studs) to 100 ft lbs and rechecked every 50 miles for the first 250 miles.
I have never had issues with loosening or coming loose do in this.
We ran a 5/8 thick spacer that was fitted to the rotor hub and the holes were sized for the lugnuts and the lugs fit down into them.
elcheapo spacers are not worth the dmage that can be done.

[Garymac69]

I'm helping a friend convert his '69 Camaro from Pro-street to Pro-touring. The rear-end is narrowed, so we need a backspacing of 3.375". The 18" wheel he wants to use has a minimum BS of 4". I see the Skultz company has a billet .625" spacer. He has long 1/2 ARP studs. What would be the pro/con of TIG welding the spacer to the wheel?