944 S2 wheel offset question
- Thread starter markrreid
- Start date
bmnelsc
New member
You shouldn't have any trouble but you should use a 5mm spacer on the rears to get back to factory offsets. The 944 Turbo optional wheels (16") were 7.5 and 9 inches and wanted standard late offsets of 52mm. The front wheels in these sets were 67mm rather than 52mm and therefore a 15mm spacer was used to effectively reduce the offset to 52mm. I believe the 67mm offset wheels were initially fit to 928s.
So - you should be good to go unless you pick extra wide tires. I have read numerous comments on 944s being "different" from side to side, etc but that seems vehicle specific...
So - you should be good to go unless you pick extra wide tires. I have read numerous comments on 944s being "different" from side to side, etc but that seems vehicle specific...
924Srr27l
New member
With a 5mm shim spacer you should have enough thread left to not have to change the studs.
Check by taking off one of the nuts and measure how much stud is left, then subtract 5mm
Also check if the centre hub has more than 5mm of spigot, otherwise the wheel will not fit dead central
R
Check by taking off one of the nuts and measure how much stud is left, then subtract 5mm
Also check if the centre hub has more than 5mm of spigot, otherwise the wheel will not fit dead central
R
924Srr27l
New member
bmnelsc said:
Adding width with a 5mm spacer on these ET47 Rear Wheels will decrease the ET number to ET42, NOT increase it to
the ET52 figure.
The best way to remember how offset numbers work is to think of the Early car's 944's inc the 16" Teledials on the Turbo used low offset numbers like ET23, then Porsche changed the and reverted back to Et55 front and ET52 rear with the D90 16" wheels on the S2
Imagine drawing a line through the centre of a wheel then measure from this to the hub mounting face, the bigger the
measurement the more the hub is towards the front face (Like the ET67 928 rims) and the lower the more dished the wheels are like early ET23 Fuchs etc..
R
924Srr27l
New member
markrreid said:
This can often be the problem with incorrect info you read or are advised etc...
Firstly what Wheels are on the car now ? Orig S2 D90's 7j & 8J ?
If so from the info on these 17" rims the differences are as follows:
Front
7" Et55 to 7.5" Et52 the inside of the rim will be 5mm closer to the strut leg and the outside of the rim
will stick out 8mm more.
Rear
8" Et52 to 9" Et47 the inside of the rim will be 9mm closer to the inner wheelarch and the outside of the rim
will stick out 16mm more.
I don't think either will be an issue, and will all fit without needing any modifications or spacers.
Tyre sizes 225/45/17 & 255/40/17
R
944 man
Active member
People suggesting that "late cars have an offset of 52mm" dont really understand offset. You could say nominal offset of 52mm (on a 7" wheel), but this will change as the wheel gets wider. Think of it this way: youre trying to keep a line that runs through the centre of the wheel rim in the same place, irrespective of the wheel's width or the way that the hub's mating surface has been machined. If you move from a 7" wheel to a 9" wheel but retain a 52mm offset then t will be in a completely different place. This is more important on the front wheels than the rears (as shown by Porsche's casual approch to centrelines vs aesthetics), but the principal remains the same.
924Srr27l
New member
944 man said:
Nominal means by name only only yes? a word I heard being used in a Michelin training session when referring to the first number of a tyre EG: 225 which they said is by name only and not the actual section width..
Only the later 944 7J fronts were ET55 and the rears ET52 in 16", except the Forged type 7x16 ET65 (951 Part number) and their rears from the (928) 9J Et60 not ET67. And Et52 in 15" all round
Porsche certainly did seem to make a hash of the various combinations the moment the early 944 was produced, quite why they decided to leave the front wishbones the same length as the 924 but in essence stick wrong and incorrect sized (ET23) offset wheels on it to fill the wider arches??, which of course totally messed up the KPI, the scrub radius and geometry!
This is why the steering on a Manual rack on early 944's is harder to turn (than a 924S) and the revised later 944's with longer wishbones
Strange why they decided to do it properly and revert back to Et 50's offsets although the strut angle was now jacked outwards more than previous which I think still affected the original negative scrub radius as originally designed for project EA425.
The first 944 Turbo Teledials did have ET23 offset front and rear, as did the 2nd gen Et52.3 all round.
The good thing is there are many combinations available not just in the 944/968 ranges but also the Boxster, Cayman and 911 wheels can all be used...
R
924Srr27l
New member
944Turbo said:The nominal width comment reminds me that the N type (Porsche spec) Bridgestone S02 225/17 was wider than the 'non N type' 225/17 by about 12mm maybe they didn't have a mould for 232/17!
Tony
Yes I'd never heard of this either until Michelin informed me! , but as you say it does explain why when people change from one brand to another why some brands have a narrower or wider tyre width, and this Industry terminolgy means the manufactures can vary the actual size as it's by name only and doesn't have to be exactly as described & Measured!
Here's a shot out the Michelin book on the 225/45/17:
SW = Section width
OD = Overall diameter
RC = Rolling Circumference
SLR = Static laden Radius
Their 225/45/17 section width is 234mm but just above this their 225/50/17 is 242mm wide !
R
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