Widening Aluminum Fuchs alloys

kenikh · 10:22 AM

I decided to pull this question out of the other thread:

911R wheel alternatives

The question:

In the search for the appearance of originality, has anybody tried widening early 4.5/5/6 inch alloys to 7" (ala 911R)? Has to be cheaper than the 6 grand for a set of real 911R wheels. Using the 6" alloys would result in nearly an exact copy of the 911R wheel (a spacer might have to be used):

The offset would be different, but I think that is just a symptom of 6" vs. 7" width, correct?

Zeke · 02-22-2005, 10:38 AM

Contact Harvey Weidman.

Wil Ferch · 11:05 AM

OK...let's get a cup of coffee and do the math:

CASE 1...using 4.5" rim:
4.5" = 114.3mm overall width.
Half that is about 57.2mm
Mounting plane is offset a further 42mm.....therefore 42+57.2= approx 100mm backspace. Checks with chart.

If you take this wheel...and add another 38 mm to the INSIDE, you get
backspace= 100+38= 138mm.
new overall width= 114.3mm+38mm= 152mm.
152mm = 5.99" width. Checks.

Yep..you'd get a 911R wheel if you took a normal 4.5" wheel and added ALL the extra 38mm ( 1.5") width to the inside.

CASE 2:
using a 5.5" rim.
5.5" = 139.7mm overall width. Call it 140 mm.
half that is about 70mm.
Mounting plane is offset a further 42mm. Therefore 42+70= 112mm backspace. Checks with chart.

If you take this wheel, and add 26mm to the inside...that would give you the same as the 911R's 138mm backspace ( 42+70+26=138mm). However, this would give you an overall width of 140+26=166mm ( 6.5"). So...something has to give, rim is 1/2" too wide on the outside.

CASE 3:
Etc, etc......follows the same thinking.

Seeing that aftermarket guys can give you custom made 17" in any offset /backspacing combo you wish....using the 6" as a core because of its FLAT FLANGE right past the spokes....maybe the 6" can still be a basis but would require both outboard and inboard custom pieces...essentially a custom 3 piece wheel to mimic 911R.

Wil

randywebb · 02-22-2005, 11:28 AM

Then there was the stmt by Bruce A in his book that the 911R offset wasn't really right either. He didn't say what it should be tho.

What should it be? And why? or do you disagree with him?

Wil Ferch · 02-22-2005, 11:50 AM

There may have been a question of it being 45 vs 49 mm offset......

I think all now agree its 49 mm for the 911R.

I also recall .....when I was offering editing advice for his second edition printing of his performance book ( how's that for name dropping !!!)...that the listed parts number for one of his 6" wheels was wrong....something like 361 was shown transcribed as 631, or somesuch......( for example, 901.361.012.04 had 631 for 361..)

Wil

kenikh · 02-22-2005, 12:57 PM

We are all agreed that the offset is a constantly moving variable dependent on rim width, as it is calculated as “rim midline from hub mating surface”. Thus:

911R
7” * 25.4 (conversion) = 177.8mm/2 = 88.9mm (midline of rim)
138mm (backspace) – 88.9mm = 49.1 mm offset (checks with drawing)
177.8mm – 138mm = 39.8mm (rim width outboard of hub)

39.8mm + 138mm = 177.8 (total width checks)

15 x 6
6” * 25.4 (conversion) = 152.4mm/2 = 76.2mm (midline of rim)
112mm (backspace) – 76.2mm = 35.8 mm offset (checks with drawing)
152.4mm – 112mm = 40.4mm (rim width outboard of hub)

40.4mm + 112mm = 152.4 (total width checks)

Given rounding error to only one/tenth and I think we have a match. Why wouldn’t I then just be able to add an inch to the inside of the 15 x 6 to get a 911R facsimile?

Am I missing something here?

Miguel Antonett · 02-22-2005, 01:15 PM

Contact Lindsey Racing, Mike will solve your problem. The P2's are as originally looking as it gets.

Lukesportsman · 02-22-2005, 06:01 PM

Kenikh :

I'm with you. It surely looks as if the numbers add up. I think if you went with Lindsey and had custom rims made, you could easily get 7.5"s in the back and still look similar to OEM Fuchs.

kenikh · 02-22-2005, 06:05 PM

If I go the custom route, they will be as wide as possible. If I could get 225s back there at a profile reminiscent of older tires (not too low) I would be in heaven.

Shuie · 02-22-2005, 06:17 PM

Quote:

Originally posted by Zeke
Contact Harvey Weidman.

Good advice here. Harvey (530.534.7903) has this figured out. You can actually go a little wider than 7", IIRC.

Shaun @ Tru6 · 02-22-2005, 06:41 PM

Quote:

Originally posted by Shuie
Good advice here. Harvey (530.534.7903) has this figured out. You can actually go a little wider than 7", IIRC.

$/wheel?

Shuie · 02-22-2005, 06:49 PM

I dont know how much, never asked him to do it. I remember the number I heard (not directly from Harvey) was lower than I expected. You may want to give him a call. He is the best of the best when it comes to these wheels.

Bobboloo · Bobboloo's Garage

The deep six is the only wheel that will look like a 911R when done. The 4.5 and 5.5 can be widened but they won't look like an R wheel when they are finished. Especially the 4.5. The 5.5 would look close though.

Shaun @ Tru6 · 02-24-2005, 04:52 AM

Left a message with Weidman's (receptionist? wife?) yesterday. He was painting. Have not heard back from them.

Will post when I do.

Soterik · Soterik's Garage

I'm having a set of wheels widened by Harvey right now.....doing all 4. Cost is about $2,200 for the set including refinishing.

Note that I have a set of 911R's (real) on the back of my 67S, and I am able to get 225's (50 series) stuffed back there with the fender lips rolled and the spring plate bolts shaved down. You "may" be able to get a taller series tire on a LWB car....but I haven't tried yet.

Eric

kenikh · 02-24-2005, 08:51 AM

Quote:

Originally posted by Soterik

Note that I have a set of 911R's (real) on the back of my 67S, and I am able to get 225's (50 series) stuffed back there with the fender lips rolled and the spring plate bolts shaved down. You "may" be able to get a taller series tire on a LWB car....but I haven't tried yet.

Eric

Pics? How heavily rolled are the lips? Is it noticable ot just slight? I'd love to see it...

Shaun @ Tru6 · 02-24-2005, 09:02 AM

Quote:

Originally posted by Soterik
I'm having a set of wheels widened by Harvey right now.....doing all 4. Cost is about $2,200 for the set including refinishing.

Note that I have a set of 911R's (real) on the back of my 67S, and I am able to get 225's (50 series) stuffed back there with the fender lips rolled and the spring plate bolts shaved down. You "may" be able to get a taller series tire on a LWB car....but I haven't tried yet.

Eric

Thanks Eric. To be very clear, total cost would be something like:
$1300 for a set of deep 6s needing refinishing

$2200 to widen and refinish all 4.

$3500 for a set of 7Rs

Is that correct?

I want to put 7s on the back of my E and 6s on the front with an RSR style finish: frosted paddles and barrel with polished lip.

Soterik · Soterik's Garage

Prices are correct....roughly. Personally don't know anyone running 7R's on the front though......and not sure of the clearancing issues....I'm running deep 6's right now, with 205/55's

I'll try to post a pic tomorrow, the lips are farely loosely rolled, no change to the visible outer lip.

Eric

kenikh · 02-24-2005, 09:50 AM

Quote:

Originally posted by Shaun 84 Targa

$3500 for a set of 7Rs

Is that correct?

Is this in reference to toal cost to build the wheels or the actual cost of buying a real set? I thought a full set of 911R wheels was about $6K.

On that note a set of deep 6s with only two wheels widened would only cost a grand total of $2400 (full set of deeps 6s + widening two to 7R spec).

Pretty compelling option, especially if the 7s are poor fits up front.

Soterik · Soterik's Garage

Correct, you can get the "total" down a bit, by only using 6's up front.

Real 7R's run about $2,500 a pair, though most people are asking higher.....then you have to consider refurbishing.

Eric