Reducing centre bore fitment on alloys ?

[BigTartanJudge 0]

Hey all,

 

Is it possible to convert a set of alloys with 72.6 mm centre bore to 57.1 mm centre bore with spigot rings or by some other method ?

 

Any help appreciated

 

Cheers

[sciroccotune 0]

Only reliable way would be to have new spigot machined really..

 

An engineering company should be able to do it for you wit aluminium

[Henny 0]

7.75mm thick spiggot rings would need to be made of something a little harder than plain aluminum or plastic IMHO... Personally I'd go for an alloy like Duralumin or similar... (pretty much what my custom spacer/spiggot rings are made of 8) )

[BigTartanJudge 0]

So how much are we talking here to get a set of these spigot rings made and does anyone know of companies that fabricate them ? Where did you get yours made Henny ?

 

Cheers

[gradeAfailure 0]

You could probably do worse than giving these guys a call...

 

http://www.wellaheadengineering.co.uk/

[Henny 0]

I got mine made at a local engineering shop I know... If you take in the exact dimensions to a decent small engineering shop and let 'em know what they're for they'll knock you up a set pretty quickly for not much cash...

 

My spacers cost £25 each, but they're substantial bits of kit - 26mm thick piece of metal machined down to give the spiggot bit and the 11mm spacer... A set of spiggot rings shouldn't cost you much at all... just make sure you get the flange machined onto the mating face so that they fit flush...

 

(look at the photos in H-YYU's gallery to see what I mean about the flange)

[BigTartanJudge 0]

Yeah,

 

It's just that the wheels concerned (8 x 17") need hub adapters (20 mm minimum) to fit 4 or 5 x 100 PCD already and this will reduce the offset from ET38 to ET18 so I really need to get spigot rings that don't have spacers attached. I take it you can get these made as well ? So I need to ask the engineering shop / fabricators to make spigot rings ? What dimensions would I need to give them etc ?

 

Cheers for the help guys

[gradeAfailure 0]

Seeing as the centre bore of the new wheels is larger than the VW centre bore, you could have the hub adaptors machined to include a hubcentric centre bore of 76.2, no?

[Henny 0]

Struan, Let me make this as simple as possible as you seem to be getting a little confused... basically you're just asking for bits of pipe to be machined out of a solid lump of Duralamin which have an outer diameter of 72.6 mm and a centre bore of 57.1 mm and are between 10 and 15mm long... they need to have a slight flange/chamfer on one end so that they'll sit flush against the disk on your car... Spiggot rings really aren't rocket science...

 

If you're using 20mm hub adaptors, unless they're hubcentric and include a spiggot flange, you'll need to add on 20mm to the length of the spiggot ring so that they still fit onto the hub and still reach into the wheel to keep it centralised.

 

You don't need spacers attached to the spiggot rings, mine have 'cos I needed to space the wheel by 11mm, but I could have just had the spiggot bit made if I didn't need the spacing... (although I'd have bought them from Borbet 'cos they make 'em for the wheels I have! :lol: )

 

gradeAfailure, that's exactly how I had my spacers made... ;) Personally I thought that it was a neater and nicer solution to the problem...

[BigTartanJudge 0]

Ok,

 

The wheels concerned are 8 x 17" size, PCD is 5 x 120, using 20 mm spacers PCD will then be ET18, centre bore is 72.6 mm. Can't machine out the adapters as then the hubcentric adapters wouldn't fit onto the hubs. So I am guessing here i will need a set of spigot rings made with a thin hubcentric flange ?

 

Cheers and sorry for confusing / gertting confused, just don't want to buy a set of wheels then find out I can't use them !!

[W3RKD 0]

henny's post makes sence to me too

[dinkus 10]

Struan - What the guys are saying is the ideal situation is to have a single-piece made up that is both a hub-centric adapter and spigot ring in one.

 

So it'll look like a disk with a tube sticking out of the middle. The disk acts as a hub adapter, so has the different holes in it and the tube bit fits in the middle of your wheel to change the bore size.

 

If you took a cross section, it would look like a letter T with a vertical hole down the middle.

 

However, you can get this in two parts, so the current hub-adapter you have is the disk and you could then get a spigot ring that is just a tube of metal that fits into the wheel. The guys are suggesting that this tube should have some kind of lip on it to make sure it stays in place in the middle of the wheel and doesn't fall out.

[gradeAfailure 0]

Cheers Dom, that's what I was trying to say!

 

Far better to have it all as one piece, and sell the hub adaptors you have already. Any good machine shop will be able to make up a combined adaptor/spigot ring out of a good strong alloy, and probably helicoil the threads for the wheelbolts for extra strength too...

[Henny 0]

which was what I was also saying... :lol:

 

Struan, where are you getting your adaptors from? Every adaptor I've seen of this type has got a spiggot shaft built into it, (like my spacers have) normally to suit the type of wheel they're adapting to (ie a porsche one will have the outer diameter to suit the hole on a porsche wheel) What you need to do is find out what the outer diameter of that is on the adaptor and then get a spiggot ring (or have one made) to suit both that shaft size and your wheel...

[BigTartanJudge 0]

Sounds good guys, cheers for the info, handy that Wellahead engineering is in Aberdeen ! Will contact them and try and get a set of combo. adapters and spigot rings made up. Would someone be able to tell me the diameter of their adapters they use to change PCD e.g from Porsche to 4 x 100 PCD or similar. I also need to know the thread pitch / size of the threaded bolt holes and diameter etc. to give to the engineering company. Many thanks in advance

 

Cheers

[Henny 0]

For the spacers I had made up I measured how big the diameter of the mounting face of a front disk was and used that for the outer diameter...

 

Can't remember what it was off hand though... :|