Machining wheels offsets

[Jez]

I've done a search but couldn't find anything on this. My new wheels are ET15 and I'd like to machine the hub mounting face to increase the offset slightly. Only talking 5-10mm.

Is it possible? Is there anything I need to be aware of? How much material can be removed? Anyone here done this?

I guess it all depends on the wheels in question but I was just looking for any hints, tips, advice etc.

[waveman1500]

Danger, danger!!

Unless you're a qualified engineer and a skilled machinist, I don't think it would be safe for you to remove anywhere near that amount of material thickness from any part of the wheel, let alone the mounting face! Even if you were suitably qualified and had done the maths precisely and determined that it was safe, the wheels would still be illegal unless they were officially tested and approved as a new wheel design.

I'd really recommend buying different wheels which actually suit your needs, or just keeping these ones as they are.

[cobblers]

You cannot usually remove material to increase the offset, because the bolt holes are usually drilled most of the way through (otherwise you'd need mega long bolts)

Taking 10mm off would mean probably mean the mounting face ends up halfway up the wheel bolt taper.

[VW]

Ive read about this being done before.

It was generaly considered safe but all depends on the wheel in question.

Someone was taking 8mm off theirs.

As mentioned though, the bolt holes are recessed, so check what thickness you have.

I think the thread was on the H.A.M.B. and was based around slot mags, should come up eventually with a bit of time spent searching.

Was quite a common practice i believe.

[Tefal]

what wheels are they?

[JohnnySomersett]

Apr 23, 2009 15:50:37 GMT waveman1500 said:

the wheels would still be illegal unless they were officially tested and approved as a new wheel design.

The rules arent as strict over here

[waveman1500]

Apr 23, 2009 19:27:06 GMT JohnnySomersett said:

The rules arent as strict over here

You can say that again, you lads even seem to be able to get away with banding steel wheels! That's a big no-no down here, you are only allowed one circumferential weld, which means you can weld your centres onto bigger rims (like on my bug) but not insert a band of extra steel. Much safer, and not really that much more expensive.

[shatmepants]

We have done this to many, many wheels. The magic number for the thickness of the wheel through the lug hole (as measured from the base/bottom of the lug seat down to the wheel/hub mounting face) is around 8mm for a cast wheel. Forged or billet wheels can go down to about 5mm.

[Jez]

Thanks chaps, I'll get a picture of the hub mounting face and try and get some measurements of the depth of the bolt holes and stuff. It's a bit tricky as I don't have the wheels yet!

[rmad]

I took a bit off the back of my AMG replicas on my old bus...the design meant there was definitely room to do so.

[Jez]

Well I've measured from the bottom of the bolt seat taper to the mounting face and it's only about 10mm so I don't think I'll touch them!

Thanks everyone.

[BenzBoy]

Am I getting this around my neck, or would machining the hub face of the wheel decrease the offset?

[Deleted]

The slotmags on my 100E stuck out too far and I wanted them well tucked under so I put them on the mill and took about 1/2" off the mounting boss on the back. They had a huge chunk of material on the back to work with though.

[Adam]

Jun 2, 2009 15:22:32 GMT BenzBoy said:

Am I getting this around my neck, or would machining the hub face of the wheel decrease the offset?

Nope, increase it! Think of it as tucking the wheel further into the arches, like a higher offset wheel would.

[BenzBoy]

Aaah OK I get it now... I'd got negative and positive offset mixed up in ma heed. ;D