17" WHEELS.

[AndyRR]

Does anyone know for sure what 17" rims fit straight on to an S2 Cab, will 964/993 wheels go straight on or are the offsets different, come to that, does anyone know what the offsets should be for 17's only you often see cup 1's and 3 piece split rims for sale but with front tyre sizes for a 911 and wondered if they are the same rims, Ta!, Andy.

 

[Guest]

Not sure of the wheel sizes but you will also have to change the front castor mounts to the later style ones as fitted to the 968 if you want to fit larger than 16" wheels to a 944.
This is a Porsche recommendation.

Cheers, Tim.

P.S. apparently it's not too expensive or difficult to do yourself.

 

[John Sims]

apparently it's not too expensive or difficult to do yourself.

Except that you need to have the suspension alignment checked and re-set afterwards.

Many of us have been running 17" wheels on the old caster mounts without problems. The 968 caster mounts have less rubber and, apparently, help to reduce tramlining which can become more apparent with 17" rims.

The main change isn't the rim diameter, as the lower profile tyres mean the overal diameter remains the same, it is through an increase in width.


edited to take out some of the spelling mistakes

 

[Guest]

Over here "acrossed the pond", I have seen 3 separate cases of the original caster blocks failing on 944 cars after owners have upgraded to 17" wheels. By "failing", I mean that the rubber center has been torn out and there is a large amount of play/movement. Nothing catastophic, but bothersome, none-the-less.

Regards,

Jeremy

 

[Diver944]

These are the offsets that fit the ABS equipped cars like your S2:

Front

7" with offset ET55 and 205/50 ZR17 tyres
7.5" with offset ET65 and 225/45 ZR17 tyres

Rear

8.5" with offset ET50 and 255/40 ZR17 tyres
9" with offset ET55 and 255/40 ZR17 tyres

See the alloys section of David Sims excellent website for full info on the new mount and castor setting www.944turbo.org.uk

 

[AndyRR]

Thanks guys that's a real help, already got the 968 front bushes and geometry set for 17's, just need to find some cup 1's or split rims, Andy.

 

[2alexcoo]

Andy, when looking at Cup 1s bear in mind that most of them out there are replicas (usually Mille Miglia) not genuine Porsche. The replicas are a lot heavier, which is why I'm sticking with 16s unless I can find an OEM set at a good price.

 

[AndyRR]

Thanks Alex, I'm O.K. with good quality replicas, a few kilos on a cab probably won't make a lot of difference as it's heavier than a coupe anyway, besides I'm no lightweight so it may encourage me to go on a diet!!, Andy.

 

[944Turbo]

But unsprung weight - bits 'downstream' of the springs is the enemy of suspension designers - I am not sure how much extra weight we are talking about with the replicas though,
Tony

 

[2alexcoo]

From http://www.wheelweights.net:

Porsche 968 17" wheels (presumably cup 1) 20lb front / 23lb rear
Porsche 993 17" wheels (presumably cup 2) 18lb front / 19.5lb rear
Mille Miglia 17" Cup 2 replicas 24lb front / 26lb rear

So comparing like with like (cup 2) they appear to be about 3kg heavier per corner. As Tony states, unsprung weight has a much larger effect than sprung weight - I read somewhere that as a rule of thumb, a pound of unsprung weight saved is worth four pounds of sprung weight.

 

[NorthernBloke]

Andy

I don't want to hijack your thread but wondered if anyone could tell me the sizes of the standard turbo wheels, ET tyres etc as I'm thinking of getting some for my S2

Cheers

Andy

 

[AndyRR]

Thanks folks, bought a set of split rims from PWS, look good and improved the handling, Andy.

 

[John Sims]

Well done Andy,

When do we get to see the pictures?

 

[AndyRR]

When my 17 year old daughter shows me how to post it, it is true that teenagers know everything!!, Andy.