hacker-pschorr

No, I'm not looking for Stan's negative spacers.

Wheels have been cut apart, and widened; I have a pair of phone dials like this. Is there any reason why a good machine shop couldn’t cut down the inside of a wheel a few millimeters to increase the negative offset? There are plenty of 8” Porsche wheels between et50 & et55 all over ebay.

Sorry if this is a stupid question, just frustrated finding wheels to fit properly without having custom made race wheels.

Secondary comment:
So far the best wheels I have found are 8x18 et57 & 10x18 et58 Carrera wheels. Right now I'm running 8x17 & 9x17 on my track car @ et52 front / rear. You cannot fit the tip of your finger between the tire and the fender with these wheels. So I’m thinking, increasing the front to et57 and the rears to et58 should work out well. Thoughts?

EDIT - replaced camber -> offset from original post

Scott M.

Hac;

I do believe you mean offset, and not camber. Camber is adjustable, offset isn't.

Cutting the mounting boss of a rim has been done, but careful attention needs given to the thickness of the lug nut seat area, and is not a great idea.

ErnestSw

I asked the same question a couple of years ago and the consensus was that it wouldn't be safe to make the mounting surface any thinner than it already is.

hacker-pschorr

I agree, however some of these wheels have a huge amound of material mating upto the hub. I've seen Porsche's with wheels that look like they have a 2" space on them. Seams like an inch or so could be cut out of there. My neighbor has the repo Cup 2 wheels from the tire rack. I think they are et52 or et55. If you look at the wheel on the car, it looks like a huge spacer on the hub, it's part of the wheel.

mspiegle

So, if you aren't allowed to cut material away from that section - then how can you have the same wheel in multiple offsets? do they really have a new mold for each possible offset of a wheel? That doesn't sound right to me...

Imo000

I believe they have one mould for various offsets. The problem is not how thick the “hub” part of the rim is but rather how deep the stud holes go. I think they machine the offset of the rim first, then they drill the stud holes. These holes will determine how thick the mounting material will be on a rim. Once the holes are drilled there is only so much material left to do any additional machining.

hacker-pschorr

That makes sense, same way they can make multiple wheels with different bolt patterns as well.

To bad we cannot get a group buy together with the replica makers for some et67 front wheels. I'm sure if we gave them 10 orders it would be worth it for them to make the wheels. Some of us (like me) really like the GTS wheel, so it's not a matter of trying to find something cheap, but what we like in a size that fits.

A friend of mine has replica Porsche GTS wheels on his Audi UrS4. They look like an exact copy of the replica Porsche wheel many of us own, with different holes drilled out for the Audi.

cfc928gt

Yes, the face can often be safely machined down some. I have a wheel guy with 25 years in the business who did that on one of my sets. He machined off about 4 -5 mm. Any more than that and you need to reinforce the holes.

heinrich

You don't want to increase the negative offset .... (these aren't the droids you're looking for...) ... you want to *decrease* the positive offset . If you really wanted to increase negative offset, you would have to take a wheel with negative offset and increase offset in the direction it already is offset.

FlyingDog

Oops. My brain is pretending it's opposite day.

heinrich

Matt, negative offset means that the rim centreline is to the *outside* of the mounting surface.

heinrich

http://www.rsracing.com/tech-wheel.html

SwayBar

Correct.

Not quite!

Offset is the distance from the centerline of the wheel-width to the mounting flange of the wheel. Increasing the offset for a given wheel-width will move the mounting flange further away from the centerline. This will pull the entire wheel in closer to the engine, and away from the fender lip.

Therefore, what you want to do is increase the 'positive' offset. This can be accomplished by milling the mounting surface of the wheel, but there's no way I would run such a wheel on the track.

928ntslow

This is why there are 2 and 3 piece wheels. I would find out the minimum amount of material needed between the lug nut mating surface and the wheel mounting surface to determine what is safe. All wheele are rigirously tested before they go to production. a mm or 2 may not be that big of a deal, though it depends on the wheel. You could shave them off and mount them. Go drive the snot out of the car on a track doing some foolish things to see how well they hold up.

How about rolling or flaring the fenders a tad...probably easier and less expensive.

I tried to get someone to cut the centers out of the phone dials and no one wants to do it. (PUSSIES!)

heinrich

You are CORRECT sir ... I got too into the fun of word play, got carried away.