3/4" adapters not safe?

[WSSix]

So I am about to pull the trigger on adapters for my TA. I'm putting BMW M-parallels on the car. I can run a 3/4" spacer on all four corners. I have gotten quotes from a couple companies for 3/4" adapters. However, I have had one company tell me 3/4" isn't enough meat around the studs. That's the studs that are in the adapter. My question is how is 3/4" not enough? Yeah, it's billet aluminum instead of steel but the axle flange on the rear of my car is no where near 3/4". I believe the thickness of the front Kore3 hubs is right around 1inch at the studs. With what I know and understand 3/4" is plenty. However, I'm not arrogant enough to believe I know everything. So can someone explain to me how 3/4" could not be enough? All companies use the same grade aluminum.

Thanks

[deuce_454]

3/4 inch spacers is fine provided you run a longer stud.. also the bmw wheels are almost, but not quite GM bolt patteren.. now, ive driven 2 full summers with bmw wheels... and never had a problem.. but the correct way is to use a spacar that is hub centric..

and use conical washers under flat lug nuts .. that way you arent putting any sideload on the studs.. make sense?

[WSSix]

The company I want to go with has low profile acorn lug nuts to hold the adapters on to the hub or axle. I'll have ARP studs on the adapters and the hub and axle. The adapters are hub and wheel centric also. Like I said, I think I'll be fine. I just wanted other input as well.

Thanks

[deuce_454]

The company I want to go with has low profile acorn lug nuts to hold the adapters on to the hub or axle. I'll have ARP studs on the adapters and the hub and axle. The adapters are hub and wheel centric also. Like I said, I think I'll be fine. I just wanted other input as well.

Thanks

if you are using bolt on adapters you will definately be fine

[Rod P]

the days of the old cracked adapters are long gone (for the most part) back in the 80's we ran alot of sand cast wheel spacers and adapters and they used to get stress cracks in them, the new stuff for the most part are all machined aluminum or steel
try EZ Accessory (http://www.ezaccessory.com/) for the part you need :thumbsup:

[Apogee]

In my experience, the issue with the thinner wheel adapters has to do with the amount of material that is remaining under the conical seat for the lug nut. All of the force from the lug nuts is trasmitted through that conical seat, so the thinner it is, the lower the factor of safety. Due to the relative thinness of the adapter, lug nut interference with the wheel is a possibility, so it's a matter of gaining enough room for the wheel to clear the inner set of lug nuts without sacrificing more material than necessary.

For comparison, a cast C6 5-spoke wheel has ~5/16" thickness as the lug nut seat since it's pocketed on the backside. The depth that the lug nut sits in the adapter will be determined by the diameter of the 60 degree countersink, however even the shortest lug nuts will still add 1/2" or more, so you'll typically need reliefs in the wheels to clear standard, short, bulge-nosed lug nuts with any adapter 7/8" thick or less.

Tobin
KORE3