Metallurgists! ShaveOff Fuchs back??

cab83_750 · 09-29-2002, 08:22 PM

I bought deep dish "fuchs-centered" chromed wheels. Man, do I love them.

They are installed on my roller. Without professional alignment, they look like they will fit....barely!

My question would be......can the back part of the wheel (the one that contacts the rotors) be thinned out/shaved off by 1/8" and still be safe! And yes, there is about 1/2" clearance between the wheel and the brake caliper.

Any metallurgy gurus out there?

Calspeed · Calspeed's Garage

I am not sure about wheel shaving but isnt using a spacer an alternative? Where is the clearance problem? The brake only or the fender too? Maybe you can roll the inner fenders to compensate. Btw... what are the specs of the wheels?

Calspeed

Jack Olsen · 09-29-2002, 10:13 PM

I wouldn't do anything to weaken the centers.

In my case, I shaved the calipers and used spacers.

Steve W · Steve W's Garage

Make sure you really have a clearance problem first. If you do, then roll your fenders. If you still have a problem, I would machine a few millimeters from the brake disk next (the part between the wheel and the hub) before I would machine the back of the wheel.

gumba · 09-30-2002, 08:44 AM

I've had a few mechanics tell me that Porsche use to mill off 1/8" off the back of the Fuchs to move the wheel in. 1/8" isn't much compared to what the cost of milling it would be.

island911 · 09-30-2002, 09:33 AM

Machining! And here I was pondering the merits of anodized fuchs being stiffer than polished.¹
Considering many of the fit problems are from the body tolerances stacking-up the wrong way; why not try adjusting body and suspension components first?

1) anodizing aluminum sheetmetal is an old trick to add stiffness w/o adding thickness.

911nut · 911nut's Garage

It's more of a manufacturing problem really. Whoever does the milling would have to carefully fixture the wheels before the machining commences. If the milling isn't almost perfectly perpendicular to the tire bead seats on the rim you'll end up with an annoying high-speed shaking.

PB

cab83_750 · 09-30-2002, 12:21 PM

I guess I was not clear of my post (or people scan the post quickly, like I do). Anyway, my pending problem would be the wheels being sticking out. My desire is to move "MORE IN."

The back tires are 515 40 16. The rims are almost flushed with the tires. When I take the wheels off, I can probably post the exact specifications. I do recall that the offset is 5".

Rolling the fender lips have crossed my mind and will be done. Suspension adjustments have also crossed my mind. Then, as if I was bored to death, I thought I would investigate the milling of either wheels and/or the rotors (the part where the studs are mounted); what is this called anyway?

It is interesting that Gumba came with information about Porsche milling 1/8 off the wheels.

Eric Coffey · 02:15 PM

As previously recommended, I would first experiment with suspension settings (specifically more negative camber), and roll the fender lips. One question though: When you say "Fuchs centered", does that mean they are modular (2 or 3 piece) wheels? If so, you should just be able to exchange rim halves for ones that will fit.

Oh, and the things the rotors mount to are called hubs, but a lot of people refer to them as "gas burners".

ted · ted's Garage

I have seen "chromed" Fuchs with shattered centers. The concern I have heard is that the chrome process may make the Fuchs center brittle. This happened at high speed on a race course in a sweeper. I have seen the shattered chrome center and the picture of the damaged 911.

If you consider milling material off the back in addition to chrome sounds like two strikes.

If the rim was not chromed I would still first consider finding non-chrome Fuchs with the correct offset rim for your application.

Hubs/gas burner? I have heard of these rims called gas burners.

Jack Olsen · 10-01-2002, 10:22 AM

As I understand it, your problem is with the wheel centers contacting your brake calipers. Is this correct? If that's the case, machining the hub contact point (like Porsche did) would only make the problem worse. You're talking about machining the backs of the 'spokes,' right?

It's very easy to file down the fins on the 930 calipers. On the rears of my car (930 brakes 2-piece Fuchs), this is what we did. Losing the fins doesn't come with any cost, since overheating is not really an issue on rear calipers.

In front, I needed to run 1/4 inch spacers. This will solve the caliper clearance problem, and allow you to keep the calipers intact. Contact with the fenders could be an issue at this point -- but if this car is going to be pushed hard, you're going to want to run lots of negative camber, which will make a surprising difference with the point where the outside shoulder of the tire meets the fender lip. Of course, camber won't affect the caliper/spoke contact. Only spacers will fix that. In my opinion, you definitely don't want to shave the backs of the spokes, since this is such a high stress area on the wheel.

MMARSH · MMARSH's Garage

I dont think he has a problem with the wheel contacting the caliper. he just wants to move the wheel inside the fenderwell a little bit.

Correct me if I'm wrong Cab, but your talking about milling the the flat area of the wheel where the wheel studs go thru. My concern would be weakening of that area. How much can you mill there before you start opening up the bolt holes. I think youd be better off running some aggressive rear camber or better yet if possible changing the backspace of the rear wheels if they are custom made.

Eric Coffey · 10-01-2002, 12:31 PM

Yeah, what Mike said!

Oh, and Ted, you are absolutely right. the "Gas burner" term originated with the vintage Mahle wheels. I guess I have just adopted the term for the hubs as well since they kinda have that "stove top" look. Now that I think about it, I am probably the only one!

Roland Kunz · 10-02-2002, 08:57 AM

Hello

Just simple.

If you like to have a "good" looking car do what you want and move it on a trailer from carshow to carshow.

If you like to use the car as a Porsche then avoid any risks for you, your car and all the people around you.

And if you like to use your Porsche like a Yugo, ... go ahead,
even chromed and shaved fuchses are better then most cheap aftermarked junk sold to look cool for low budget.

( did Yugo workers eat rice ? )

Grüsse