I've read a number of threads in this forum, but none of them seems to quite answer this question...

My wheels are going to need 20mm spacers. I understand that using universal ones could put a strain on the wheel bearings & may cause the wheels to "hang on the bolt threads".

However, I don't fancy hubcentric spacer prices, so I was wondering whether if using spigot rings in conjunction with universal spacers would achieve the same effect as hubcentric spacers? Wouldn't the load then be taken by the hubs in just the same way?

As long as the spacer supports the rear of the wheel, and the studs are long enough to get enough nut on, then i dont see why the wheel hangs on the bolt, as the spacer fits over the hub nut, and the wheel onto the spacer.
I agree that you may need longer studs as opposed to ferrule studs as they would be stronger and eliminate the risk of stripping the original stud thread.

There is a spacer called hubcentric which has a machined spigot built in

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Originally posted by snapper
There is a spacer called hubcentric which has a machined spigot built in

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The universal ones have a special design feature that will shake your fillings out, marginally prior to knackering your balljoints. The hubcentric ones are a bit more expensive but are really the only way to go.

Spigot rings are only to adapt the inner of your chosen aftermarket wheel to your hub. Used in conjunction with 20mm plain spacers they wont have anything to locate onto s the spacers are flat. Hubcentrics locate over your original hub protrusion then have their own machined protrusion to mirror the original hub, picking up on the wheel centre, or spigot ring as the case may be.

You need to fork out for hubcentric spacers, or sell the wheels and buy ones of the correct offset.

My car can only take 5mm of plain spacer before the wheel is hung on the bolts so that gives you an idea oof how far you should go with plain ones.


ATB
Stott

These are the facts

The load transfer between the wheel and the face of the hub hub is friction alone.
The only way a wheel will "hang on the bolts" is if the wheel nuts/bolts are slack.

All spacers change the load on the wheel bearing by amount that depends only on the thickness of the spacer.

Form many years most manufacturers did no use hub centring because too many problems with wheels stuck on the hubs, the change came when manufacturers switched to for cost reduction reasons wheel bolts, with wheel bolts the wheel is usually (but not always) hub centred because of the difficult lining up the holes when changing a wheel.

Many many works racing and rally cars managed quite nicely over the years using the wheel nuts alone to centre the wheel.

Wheel centering will centre the wheel slightly more accurately (provided the wheel and hub centre are clean) but any run out of the wheel rim is trivial when you consider the run out of a tyre.

I'm running 25mm spacers, seem fine to me over 2000miles.

Davie

Thanks for the replies so far.

I was trying to avoid universal spacers cos' I'm not convinced that slots allow you to centre the spacer with the necessary precision, which might lead to balance/vibration issues. (Or am I mistaken?)

I also didn't like the fact that no part of the spacer was in direct contact with the centre of the hub, and hence the hub wasn't taking any of the weight. That's why I looked at the spigot idea. I wondered whether I could use that to fill the gap between the hole in the middle of the spacer and the hub itself. If so, then the spacer would end up a snug (tight?) fit on the hub, and the hub would then be bearing the weight. It should also eliminate any centering issues.

Am I completely up a gum tree thinking this way?
Would the thickness of the spacer (20mm) prevent the spigot making contact with the hub?

The offset I'm trying to correct is 23mm. If I did go with hubcentric, could I get away with using just 15mm, provided nothing rubbed anywhere. After all, 8mm out either side isn't too much... is it?

This is a good easy to understand write up of how hub centric spacers work

http://bernardembden.com/xjs/hubcentric/index.htm

Personally, with the power I run in my cars and the cornering loads I get I would not use anything else. Definately the way to do it IMHO!

To be honest, it is the improved centering when mounting the wheel and the fact that you don't need long unsupported studs that is the main reason to use them of course!

They have to be better when running over the curbs or hitting a pot hole in the road too! Again IMHO!

[Edited on 31/12/10 by Strontium Dog]