Machining 951 Fuchs backspace.

[ulrichd]

Came across this pic of the back of 7x16 915 Fuchs that clearly shows the profile. Has anyone ever machined back the mounting surfaces to, say the same as a 6" wheel backspace. Since so many people complain about rubbing in the front that would take care of it.

Would the fact that these are forged wheels keep you from doing so?

Ulrich

Ulrich

[p911dad]

Ulrich, that is an interesting solution. Conservative ol' me says you will join the ranks of test pilots when you start removing metal on such a critical component, considering the stresses that a wheel on a Porsche can expect to receive. Perhaps a wheel expert has a different opinion.. Glenn

[racer]

1) Those wheels are great because they allow you to run larger front calipers (think 964/944T) without running wheel spacers which push the wheel even further out.

2) You would be machining away the area where the lug bolts attached. Call me finicky, but I'd hate to find out under stress that the wheels would crack at their attachment points

[David]

I've machined the hubs on wheels in a vertical boring machine, but looking in the bolt holes it doesn't look there's room to take any material off.

[MotoSook]

I seem to recall that the 951 wheels have deeper set lugs, which essentially puts the same amount of material between the lug nut and the hub. Someone will come along and call BS or back that up, but I don't think you want to remove material from that wheel.

[gumba]

An alternative I used for more backspacing was using a 912 hub. I think it's about 1/4- 1/2" narrower than a 911 hub. I used long studs and spacers to get the backspacing I wanted. Too much backspacing will cause the tire to rub on the shock cover (I removed mine). I had 930 calipers, 8x16 951's w/225 SO3's on the front on my '73 targa.

[ulrichd]

Really interesting. Would that be a straight bolt on? Forgive my ignorance, what years was the 912 built.

Thanks.

[gumba]

Yes a straight bolt on. Not sure of the years.

[KTL]

Originally posted by Souk
I seem to recall that the 951 wheels have deeper set lugs, which essentially puts the same amount of material between the lug nut and the hub. Someone will come along and call BS or back that up, but I don't think you want to remove material from that wheel.

I agree with Souk. Despite the hub looking deeper, the countersunk lug holes establish a hub thickness (between the lug seating surface and the wheel mounting surface) that is the same thickness as a non 951 wheel. So machining the wheel mounting surface to make any sort of substantial gain in backspacing (reduced positive offset) would make the hub thickness at the lug holes much thinner. Probably not a good idea!

[ulrichd]

Originally posted by gumba
Yes a straight bolt on. Not sure of the years.

Looks like 66-69 in US. It was introduced in 65 in Europe. I assume all part numbers start with 912. What about strut shock inserts, ball joints etc., will all the current stuff fit?

Thanks.

[nesslar]

Please don't. That just looks like "asking for disaster."
How about 50 series tires versus 55 instead? Or maybe people with rubbing issues can just raise the front of the car about .125-.375 of an inch. Shouldn't take much, usually.
Seems to me our cars look better with about .75, maybe an inch, or even a bit more of 'air' under the lip anyway. Too low just doesn't quite look right, just my $.02 this time.

[gumba]

The 912 hubs are a straight bolt on. I used them on our targa (track/street car) for 3 yrs. before I sold the car. You will need to use some type of spacer as you won't be able to use the full offset of the 912 hub. These should be available from any Porsche recycle shop. You should just be able to ask for a 912 front hub.

[gumba]

8" Fuchs on narrow body 911?

I responded to the 912 hub approach a few years back. Here is the link. If you go to the 2nd page I have a shot of the 911 hub compared to the 912 hub.

[ulrichd]

Originally posted by nesslar
Please don't. That just looks like "asking for disaster."

Are you talking about the machining of the wheel? Yeah, sounds like a bad idea after the posts here.

The 912 hub is an interesting idea.

Ulrich

[ulrichd]

Originally posted by gumba
8" Fuchs on narrow body 911?

I responded to the 912 hub approach a few years back. Here is the link. If you go to the 2nd page I have a shot of the 911 hub compared to the 912 hub.

Thanks, that clears it up. For some reason I was thinking strut all this time, hence my questions about shock inserts, etc.

Ulrich

[ulrichd]

Originally posted by gumba
8" Fuchs on narrow body 911?

I responded to the 912 hub approach a few years back. Here is the link. If you go to the 2nd page I have a shot of the 911 hub compared to the 912 hub.

Check out his diagram for 65-69. Do I need everything from the left of the spindle or just the hub.

http://dcauto.gotdns.com/catalog/index.php?mode=parts&model=911-1&year=1965-1969&group=4&section=402&illo=402-05

Thanks.

Ulrich

[gumba]

Just the hub. I would also replace the wheel bearings so everything is fresh.

[ulrichd]

Just sourced the hubs from PartsHaven for $50 ea. At that price it'll be a fun experiment. Thanks very much for the idea.

Ulrich

[nesslar]

Ulrich,
Yes to all you said in reference to my "...don't do it....". I certainly fear the machining. Or rather I respect the lack of it.

[ulrichd]

Originally posted by gumba
The 912 hubs are a straight bolt on. I used them on our targa (track/street car) for 3 yrs. before I sold the car. You will need to use some type of spacer as you won't be able to use the full offset of the 912 hub. These should be available from any Porsche recycle shop. You should just be able to ask for a 912 front hub.

Hey Gumba,
Got some 912 hubs from a 68 and, looking at the pic below, they are not hubcentric for my 911 Fuchs wheels. Did I get the wrong year?

Ulrich