Vilhuer

18" Mille Miglia Cup and Keskin Speedline copies at least IIRR. There's definitelly differencees in aftermarket wheels.

ET68 for 9.5" wheel is way too little. CS/SE/'89GT 8x16 wheel has ET60. For 9.5" to stick out same as it needs ET to be 79mm. Whole point of having custom 3 piece wheels is to have them in correct offset. Which is very difficult to do with off the shelve parts. 9.5" ET68 is racing size used by factory but I bet they wouldn't use it in street car. I would also hope to use wider tire on 9.5" wheel. Preferably 285's.

DKWalser

Whether shaving a wheel works or not, and whether it is safe or not, depends on both the wheel and how well the work is done. What worked on a set of wheels from 1988 might not work on a set of wheels made today; or it might. Today's wheels are generally lighter and use less material. Today's wheels are frequently larger in diameter, which increases the leverage of forces at the rim of the wheel against the hub. And, today's tires provide more grip, again, exerting more forces on the hub. All that leaves less material that can be removed before the wheels are unsafe. But that's just a general rule, to which there are probably lots of exceptions.

There are plenty of wheels that will fit a 928 properly. Point being, unless you're an engineer who knows what he's doing, why take the risk?

hacker-pschorr

You know what a poser is? Someone who stomps into a thread, chest puffed out with information based on accomplishments..... that are not even his.

How about some specifics on said wheels? Before / after measurements, what they are made from etc.... That would be really helpful. As it was pointed out in this thread more than once, these specifications can vary.

The professional metallurgist I spoke to about this idea agrees it's a horrible and dangerous idea based on the Porsche wheels we measured.
I'll take the advice from someone who's an expert in all things metal over a "motorsports engineer".
He too has welded wheels to make them wider (my set of 9.5" phone dials came from him). Which is a totally different argument and discussion.

I've been around racing since the day I was born. I've seen some very stupid ideas work very well and win many races. Sometimes luck is on your side. Other times it's crash and burn, people get hurt.

When it comes to spreading advice across a public car forum, it's smart to error on the side of caution. What some "motorsport engineer" does with his own car and equipment is great for him.

Come back with your argument when he starts to market and sell these modified wheels with a full warranty and an insurance company willing to back his work. Then your claim of his expertise as it applies to this discussion might mean something. Until then, it's obvious who the poser is here.......

Now now, don't get in the way of "928SG" and one of his superiority rants. It's been a while.....

FredR

Erkka,

You appear to be looking at this from a completely different perspective. My point of view is simply why pay for an 8 inch width when you can have a 9.5 inch rim for the same price? To my way of thinking 8 inch rims and 225 rubber are too skinny for street and most certainly for track work.

That Porsche used the formula I have seems to say something and I would not want to run a 285 section on this size even if it would fit in the wheel well[which it will not at this offset].

I do agree that to fit a 285 section up front you would need more offset but lock would be quite restricted- albeit probably not a problem for a track machine but it would on a street car and it would be rather difficult to make even with 3 piece construction.

I am certainly very happy with this configuration and I have utmost faith in the folks who specfied it.

Regards

Fred

svpmx83

from Mercedes comparing the factory genuine wheels on the left and an aftermarket wheel on the right

The article is here

Vilhuer

My point is that 928 uses exceptionally large offset wheels. This makes it almost impossible to find wider than 8" for front end regardless of them being 1, 2 or 3 piece design. Price is part of equation but without paying for completely custom setup its impossible to find correct ET wheels. Correct ET means more than what fits well enough not to rub into fenders.

FredR

Erkka,

Exactly the point I am making- my wheels fit very well, I had to fit an additional spacer on the rack to avoid contacting the Devek sway bar [first point of contact] and the offset is optimal NSR wise. Doubtless why Porsche used that number albeit I think they used 1 piece wheels that were very heavy. That such are relatively difficult to make there is no doubt and a good set of wheels is going to cost in the region of $6k maybe more since the last time I researched the subject some 6 plus years ago.

My wheel arches are rolled and I run with 2 degrees front camber so no contact on the fenders and everything looks more or less stock except the wheel design of course.

Regards

Fred

M. Requin

I'm not an engineer, internet or otherwise, but I can add...

UpFixenDerPorsche

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