Fuchs Alloy Offsets

[Guest]

Fuchs Alloy Offsets - as follows:

Very simply, the offset of a wheel is the distance from the body face (fixing point to the hub) to the centre line of the wheel rim.

Wheels are produced in 2 basic parts, the centre body and the rim - both are then positively fixed together at differing points within the rim width. There are three alternatives : positive, neutral and negative offsets - ie, where the rim is pushed outward and away from the hub, that is a negative offset and vice versa for the positive offset. A neutral offset is where the hub face and centre line of the rim are on the same line.

Rim width is the only variation on wheel size - ie, an 8" rim will have less of a negative offset than a 7" for the rear of a 911.

The 15" and 16" Fuchs Alloys as fitted to the 3.2 Carrera come with pre-set negative offsets for the three rim widths of 6", 7" and 8" - as follows :

6 J x 15 H2 - 36,0 mm
7 J x 15 H2 - 23,3 mm
8 J x 15 H2 - 10,6 mm

6 J x 16 H2 - 36,0 mm
7 J x 16 H2 - 23,3 mm
8 J x 16 H2 - 10,6 mm

Offsets have a direct impact on the car's track dimensions - which increase or decrease accordingly as the track is measured from the centre line of the wheel/tyre. To increase the track, you will run a negative offset OR alternatively, run spacers between the hub face and the wheel body - thus moving the entire wheel outwards and increasing the track and effectively the offset from the hub face (not wheel body).

In a nutshell then, offsets are quite important to the overall geometry of a suspension set-up and are designed by the manufacturers to work with the basic principals of the car design and handling.

FYI : I am running a 'piece' on the Fuchs Alloy history in May PPost.

 

[Guest]

Hi Jon

Indeed, your 'technical appraisal' is correct but this is not a technical forum - hence the reason why I started with "very simply" - discussing offsets in gereral not the specifics of producing a Fuchs Alloy nor the forged method of production.

I am currently in discussion with Otto Fuchs KG with regards to the original Fuchs wheels and am aware of the production sequences and the reasons why forging was used - but with regards to the offsets, there has been some comment on this forum regarding wheels and I wanted simply to advise members who were thinking of switching wheels (generally due to the high cost or non-availbility of Fuchs wheels) to ensure they understood the offset figures for specific wheel widths and the use of spacers.

However, I do value your comments and would like to hear more from you off-line if you have any technical contributions to the overall understanding of the forged Fuchs alloy. Anything please, these wheels form a very important part of the 3.2 Carrera make-up and despite talking directly to the manufacturer, Fuchs KG no longer hold the tooling nor the rights to produce these wheels and hence their knowledge is in files as opposed to in engineer's heads - those now retired.

I get the feeling that you might know a thing or two?

Thanks Jon - nice to know some people actually read my drivel!

 

[Guest]

There, I've identified myself as a Fuchs nerd.

Perhaps you ought to mention the identifying features of this new breed, so that they can be (avoided ? greeted like long lost brothers ? any other option ? ) - they could even have their own register.

As an aside, I have never considered replacing my car's Fuchs, as they seem to go with the car so well, and later, modern replacements always seem out of place.
And I can't afford the cost of other strong/lightweight forged alloy wheels !

 

[Guest]

I think the problem is the cost of either used originals or replicas - cup alloys and the like are easily available and cheap.

For example, I have been looking to replace the Design 90s on my 951 Cab and both the cast replica 90 or a forged clubsport 90 cost considerably more than a set of replica cups - albeit that they are 17".

A set of replica Fuchs can set you back damn near a grand per corner - the only real option is to have them refurbed - a route I may well go down with my Design 90s. I am currently in contact with an American company that produce replica Fuchs and will advise the members when I have absolute details - but the point here, is that they are replicas and because Fuchs KG no longer produce this alloy, you cannot but a genuine Fuchs replacement.

As it happens, I am awaiting information from Porsche AG about availability of new Fuchs alloys - produced presumably in their own works?

Porsche Cars GB have directed me to Jasmine Motorsport for genuine refurbishment wheels - so I will have a nose around there as well (time allowing).

These iconic wheels are part and parcel of the true 911 and this identity has not really been emulated through the later models.

 

[Guest]

You forgot one:

+15mm o/s 9x16

Works equally well on the rear of narrow body 3.2s.

 

[Guest]

Here is the mother load of info for all you info fiends (sorry about the format and the focus on weights, but I copied it [])!

The link for it is here http://members.rennlist.com/911pcars/WheelWts.html - although I think it has a couple of typos which I corrected. There is also some aftermarket wheel info.


Factory Wheels

Description Construction Size
Weight (lbs.) Offset (mm) Backspace (mm) Miscellaneous


Mahle "Gas Burners" Pressure cast 5.5x15
9.5lbs 42mm ?mm 901.361.017.00

Fuchs Forged 5.5x14
?lbs 46mm ?mm 911.361.016.10

4.5x15
?lbs 42mm ?mm 901.361.012.01

5.5x15
?lbs 42mm ?mm 901.361.012.04

6x15
12.5lbs 36mm 121mm 901.361.012.06 (early); aka the deep dish version*
* Early wheel (w/o safety bead) may be lighter)
911.361.020.10 (late)

7x15
12lbs 23.3mm ?mm 911.361.020.41

7x15
12lbs 49mm (911R) 1145 901.361.012.05; allows larger tire on narrow body 911s

8x15
14lbs 10.6mm 120mm 911.361.020.42 / 911.361.020.12

9x15
?lbs 3.0mm 127mm 911.361.020.03 / 911.361.020.06,

11x15
?lbs ?mm ?mm 911.361.020.05

6x16
17lbs 36mm 121mm 911.361.020.43 (early)
911.362.113.00 (late)

7x16
18lbs 23mm (911) 122 911.362.115.00
911.361.020.44

7x16
23lbs (944) 112 951.362.115.00, add'l clearance for larger calipers

8x16
19lbs 10.6mm (911) 112 911.362.117.00
911.361.020.45

8x16
23.3mm (944) 135 951.362.117.00; offset compatible for front 911 application

9x16
20lbs 15mm 130mm 911.362.119.00; fits rear with SC/RS flares

Phone Dial Pressure cast 7x16
18.5lbs 23.3mm 118mm 951.362.114.00 (944)

7x16
?lbs ?mm 111mm 928.361.016.00 (928)

8x16
20lbs 23.3mm 132mm 951.362.116.00 (944)

Dish Forged 7x16
18.5lbs

8x16
20lbs

928 CS Forged 8x16
19lbs

951S/928 CS 9x16
20lbs

C2 T Pressure cast 7.5x17
22lbs

9x17
23.5lbs

993 Pressure cast
7.5x17
18lbs 55mm 993 Cup, Front

9x17
19.5lbs 55mm 993 Cup, Rear

8x18
25.6lbs 52mm 993.362.136.01, Front Turbo (solid spoke)

10x18
29.3lbs 65mm 993.362.140.04, Rear Turbo (solid spoke)

8x18
31lbs 40mm 993.362.140.03, Rear Turbo (solid spoke)

8x18
19.95lbs 52mm 993.362.136.00, Front Turbo (hollow spoke)

10x18
23.36lbs 65mm 993.362.140.01, Rear Turbo (hollow spoke)

10x18
25.13lbs 40mm 993.362.140.00, Rear Turbo (hollow spoke)

996 ?
8x18
20.5lbs 50mm 2002, Front

10x18
22.7lbs 65mm 2002, Rear

911/944 spare Steel - 34lbs w/tire

951 spare Aluminum 5.5x15 26lbs 130mm 951.362.131.00 (11.5 lbs. w/o tire)

Sport Design
8x18
26.5lbs 52mm Front 993

10x18
28.9lbs 65mm Rear 993

Sport Classic II
8x18
23lbs 52mm Front 993

10x18
27lbs 65mm Rear 993

 

[Guest]

This is even better and is what I was originally looking for courtesy of Bill Verburg.

 

[Guest]

Nope - 8. I used to have 12 wheels but recently sold 4 (non-Fuchs Compomotive 3-piece) wheels. SWMBO made me rationalise []

However, I am in the market for another pair of 7x16s - if anyone has some spares []

I must also nominate Nick Moss as Mr Fuchs - check out his early911 website. I really want to get mine refubished in the full anodised look (shown on his site in the wheels for sale section) but at about £100 per corner it is a little rich for me right now - still struggling to come to terms with the single income one kid status, I just can't hide the Porsche expenses as easily from SWMBO. I would also love to get Nick to build me a 911R replica but that is a whole other kettle of fuchs and is just a pipe dream right now.

RB

 

[Guest]

This is what I had in mind previously:

 

[Guest]

Note that the 9x16's on the last line of the above chart have the wrong part number. I made a typo when I first did it.

It should show 911.362.119.00

I did a corrected version sometime ago but once things are released onto the net they have a life of there own [&:]

Cheers

Andy

 

[Guest]

Apologies if anyone thought I was trying to pass off the chart as my own creation. I just didn't have it to hand and didn't have the time to serach when the offset topic first came up. I knew I had seen it somewhere though and recently stumbled upon it again.

Andy, this is the most useful tool I have seen regarding offsets and if you were the person who put it together, then thanks muchly.

Cheers,
RB