Centre bore

[mrmule]

So I inherited some 15 inch merc steels which have seen better days on the Doka. Its taken a while but I finally managed to get some centre adapter spoigot rings to make them properly hubcentric. I opted for the aluminum ones over the plastic. The four arrived yesterday, so this morning I set about fitting them, only to find the front hubs appeared to already have the same centre bore as the merc rims i.e. 66.6mm. The rears had the expected 57.1mm and the rings fitted well.

Am I missing something? Are the fronts a different centr bore to the rears? Or have I got some weird incorrect part fitted up front? Given some latest events, it wouldnt surprise me.

Adapter:



Rear fits nice:



Fronts:

[syncropaddy]

Em... Why have you bought hubcentric rings? The hubs are not hubcentric, you simply bolt the wheels on!

[mrmule]

The hubs are not hubcentric

Are you sure? I think they are mate.

I got them for the purpose they'e designed for. To get the wheel bolted on dead centre. It elimates vibrations at speed. Also, the load through the wheel shouldnt sit on the bolts. They just hold the wheel on. The weight should really be picked up by the centre flange thingy.

[syncropaddy]

The hubs are not hubcentric

Are you sure? I think they are mate.

I got them for the purpose they'e designed for. To get the wheel bolted on dead centre. It elimates vibrations at speed. Also, the load through the wheel shouldnt sit on the bolts. They just hold the wheel on. The weight should really be picked up by the centre flange thingy.

I know what they are for ..... T3 hubs are not hubcentric, if they were then all 4 hubs would have the same diameter and they dont! All T3 wheels would all be the same too and they arent.

[Simon Baxter]

Yeah, not really needed.
Weight is designed to sit on the studs.
Look at the standard wheels, they don't have a round centre bore, it is for want of a better phrase "daisy shaped".

[mrmule]

I know what they are for ..... T3 hubs are not hubcentric,

Do you mean to sound confrontational? I'm asking for information is all.

if they were then all 4 hubs would have the same diameter and they dont!

So we get vaguely close to an answer. Even if your are correct, is there something wrong with what I am doing?

So getting back to the original question, if VW use a 57.1mm centre bore, how come they have used 66+mm up front on the syncro?

[Simon Baxter]

Also, wheels centre on the tapered or radiused seats, hence why you have tapered/radiused wheel fittings rather than just normal flat faces.
That's why it's important to nip the wheels first then torque them.

[mrmule]

Yeah, not really needed.
Weight is designed to sit on the studs.
Look at the standard wheels, they don't have a round centre bore, it is for want of a better phrase "daisy shaped".

Thanks Si. But even you must concede that it aint a bad idea to try and centre 'em. Your Porsche adapters are hubcentric, no?

[Simon Baxter]

Just for ease of location, T3s with factory wheels do not centre on the spigot of the hub.
Up to you if you want to locate them in this fashion, Vw chose not to.
We did our Porsche adapters like that because of the extra ET the Porsche wheels have, but they don't locate to the t3 hub "hubcentricaly" if that's even a word!

[syncropaddy]

Which wheel has a 57.1 centre bore? Like Simon says all the weight is on the studs and not on the hub flanges. The Syncro hub flange up front just happens to be that size for what ever reason. The car those wheels you have came off - a Merc C Class W202 - has hubcentric hubs but not very accurate ones

Not being confrontational at all. Just puzzled by your train of thought

[mrmule]

I wouldnt say my train of thought was all that ambiguous; I just knew the merc centre bore was bigger than the VW, so I thought it best to centre them up. Didnt know it 'wasnt necessary' on the T3s.

Thanks for both your comments. Now to band the steelies...

[syncropaddy]

Thanks for both your comments. Now to band the steelies...

Where are you getting that done? Im thinking about doing that but there are good and bad places to get it done. To do it properly you need 8 wheels

[Simon Baxter]

I think more importantly is the fact you have Vw wheel nuts on merc wheels, they have a different radius, you'll end up with only a small contact patch where the radiused set touches the wheel.
From memory the Vw has a 14mm radius, while the merc only has a 12mm radius.
It's the same reason why you use different wheel nuts for merc ML wheels and Mefro steels.

[mrmule]

The T4 guys like these guys. Had a chat with them this week, and seems like its a go. Except ideally I'd like to do it to a set of 16" steels. If I ever wanna use them on my MV I need at least 16" due to the porsche calipers.

[Simon Baxter]

Wheel nuts for merc wheels
http://www.brickwerks.co.uk/shop?page=s ... gory_id=46" onclick="window.open(this.href);return false;