Newbie question - what are the offsets on my mag wheels?

[jimmyslr]

Looking at getting some spare wheels to put some track rubber on and wondering what i should be looking for...

Fronts: 7.5Jx17 - but what's the offset?
Rears: 9.0Jx17 - again, what's the offset?

Current rims are painted and cannot see any markings to say.

Thanks, James.

 

[s west]

The orignal magnesiums are ET 55 front and rear. As I'm sure you know the magnesium wheels are no longer made, there are some new ones around but they seem to be about £1000 each so proabably makes sense to look for altenatives for track wheels. Genuine Porsche Cup 1 alloys are available in 9's ET55 but the only alloy 7.5 is off the 968 and has an offset of 65mm so you would need 10mm spacer (probably could run 15mm) and longer studs. It is possible to run the Porsche 8J ET 52 on the front but clearance can be a little tight. I have been told to avoid the Mille Miglia replica Cup 1 wheels for track use as there have been cases of these wheels breaking. Not sure if this is rumour or fact but it's enough to put me off!
Hope this helps
Regards
Steve West

 

[pressing]

jimmslr, you could always buy the track wheels Russell (your car's previous owner) has?

 

[jimmyslr]

Interesting, so what other wheels do people run if they change for track days? How about the BBS racing ones (a la Le Mans cars), which I now understand come in aluminium rather than magnesium?

 

[pressing]

BBS have stopped producing the three piece race wheels with Magnesium centres. They now come with alluminium centres. I have a contact within BBS AG and they are around £2000 delivered to the UK.

 

[zub]

Jimmyslr you know you need some BBS split rims they will look awesome on your car, and when they're not in use you can use them on your Caterham...

 

[oldtimer]

I suggest you put the track rubber on the original mags and use them for track as they are meant to be used...like the rest of the car. Its not a garage queen nor is it cheap to buy and run anyway so whats the problem? Use a second set of wheels in the readily available 7x17 and 9x17 size with 55mm offsets for normal road tyres and 'everyday use'. If you don't like that idea then suggest you contact Jasmine who are knowledgable about what will fit and have some good stock of used genuine Porsche alloys....I found that 996 wheels 7inch fronts and 9inch rears 17 inchers are cheap s/h , and if you get the MY 98/9 Carrera 4's these are not twist look. Original Cup 1s (964s) and Cup 2s (993s) are getting harder to source.

 

[lee fulford]

I change for the original Mags for track days with Cup Sports.
After all thats where you'll notice the difference and the light mag wheel will come into its own.

lee
P.s...By the way oldtimer I prefer garage King to Queen please.