Non hub-ceNtric mags quattro Digest, Vol 35, Issue 26

[SuffolkD at aol.com]

Not an endorsement, but the aftermarket 15" rims I have on the 4000Q came 
with cone bolts.  Unknowingly, I used them for 5 years with no ill effects on the 
street.
The specific reason the tire wholesaler sent them as a kit was that the OEM 
bolts held the rim on by two threads,  Rim was thicker materal. Hence the need 
for longer "bolts"..............

However, concerning Hubcentric rims.  Rims made "hub-centric" have a flange 
which the rim sit / rests on the Audi hub flange which supports the majority of 
the weight.

The bolts merely hold the rim to the hub assembly.

While a track environment is much more harsh than every day street driving; 
(sans potholes) I have seen an Audi 90 without hubcentric rims sheer the bolts 
right off the sedan at a track event at NHIS in turn 10.  While its debateable 
if the actual fatigue was caused on previous use and/or every transition at 
the facility or the turn 10 apex MOUND which is similar to jumping a curb if 
hit square on.  That being said, its not the only instance where rims used for 
the track have sheered wheel bolts off, but this is one of two which I can 
confirm which were NOT hub-centric.

While conical aren't the perfect centering bolt choice for OEM Audi hubs, 
they work if care is taken using them while mounting the rim to the car.

Its apparent by shape alone that the pressure is focused in a more 
concentrated area of the rim casting than the ball bolt seats provide, but as long as 
the hub & rims are hubcentric, the bolts only keep the rim fixed to the hub 
assembly..

Here's a web site I googled about; "Hubcentric," which they talk more about 
centering the wheel to the hub vs sheer forces applied to the wheel 
bolts................
http://www.miata.net/garage/hubcentric.html

That's what the nylon or plastic "rims" do................they take up the 
space between your rim hub diameter and the hub size of the auto they are put on.

HTH
-Scott by BOSTON


> 
> Considering that most of the hub centric rings I've seen seem to
> be made of nylon. Don't think they're carrying any (in this case)
> compressive loads of significance. Now, what REALLY is keeping
> the shear loads from the lugs is the compression of the wheel hub
> against the axle hub, which supplies an impressive amount of frictional
> force with properly torqued lugs. Hence, very little lateral (okay, shear)
> loads on the lugs. And the pre-load due to to the provided torque should
>