On Sat, 28 Apr 2018 22:33:14 +0100, Roger Mills
wrote:

On 28/04/2018 19:47, T i m wrote:


In contrast, 'stud centric' wheels rely on the friction generated by
the clamping force of the fastenings to allow the load to be
transferred to the hub, not requiring (or even having) and contact
between the vertical edge of the wheel hole and the hub. This is fine
if that's how they were designed but not a good thing to do if they
weren't. I think this is one of the reasons why many aftermarket
wheels come with Spigot Ring / adaptors.


But these adapters are usually made of plastic.

Many are but the 'better ones', are made of alloy.

I don't know how much
load they would take.

Well there are plastics and plastics of course, some being very strong
(especially in compression)

AIUI, their purpose is to locate the wheel so it's
concentric with the hub

Understood, that is definitely one of their roles.

- but you still need the clamping force of the
studs to support the vertical load

Ok. Take a wheel off a car (that is 'hub-concentric) that has not been
off for some years. Often, even after removing all the fasteners it
could actually be driven on (slowly) without any issues. How much
*vertical* load (eg the mass of the vehicle and the spirit of this
question) in that instance is being carried by the fasteners? (The
answer is obviously 'none').

and to transmit drive (not on a
trailer) and braking torques.

Of course, but I am only really discussing the basic principles of the
difference between stud (lug) and hub centric wheel fitting.

Most wheel nuts are conically faced, as are the mating points on the
rim and so should (potentially) 'centre the wheels on the hub as they
are tightened up. However it seems they often don't for those running
aftermarket wheels without spigot rings (or even bad spigot rings that
don't provide a reasonable interference fit to the wheel centre and
hub).

So, are you saying that in fact any wheel on any (conventionally
wheeled) car wouldn't need to rely on hub-concentricity, once the
fasteners were tightened correctly ... if the spigot ring could be
removed after the wheel was fitted?

Cheers, T i m