Jeremy Pinsly

Adrian,

I need your opinion on this one........

I have been considering putting 18" RUF (8x18, 10x18) wheels on my 1990 C2 Cab. The suspension is stock. The car is not being used for track events. I want to change the wheels purely for cosmetic reasons.

I understand that Porsche has never approved the use of 18" wheels on the 964. I think this is because the stock suspension can't handle the increased load from these wheels?

If the wheels fit on the car, why wouldn't I be able to use them? Aside from ensuring the wheels clear the oil lines in the rear and the steering stops are replaced, are there serious issues with running 18" wheels on this setup?

I am very confused about the differing opinions on this matter.

Thanks in advance,

Jeremy

Adrian

Dear Jeremy,
I am running 19 inch Sportec wheels myself at the moment however they are going through a Swiss and German certification system to get approved. Stress testing is part of the process but the results will not be known until the next level of inspections are carried out after winter. They will be removed for winter.
Sportec are also developing (prototype fitted to my C4) DIY steering stop replacements.
You are correct that the current crop of 18 inch wheels are not approved by Porsche for the 964 normally aspirated cars.
The RUF wheels are in my personal opinion too heavy for the normally aspirated 964 with the stock suspension.
They are okay for the RUF models like the RCT Evo with nearly double the HP and the suspension to suit.
I still believe in fitting approved and tested wheels but that is just me.
Also remember that the front of a C4 is somewhat stiffer and stronger than the C2. It was the 1990 model year C2 that had the problem with front wheel carrier covers.
Ciao,
Adrian
964C4
GT-2

MacFever

I have put boxster wheels on mine without spacers !

BGLeduc

19" Adrian?

Sir you are so hard core!

But then again, with, what is it, +50HP after the Sportec update and a ton more torque, I guess your C4 has what it takes to spin those big wheels now.

BTW, any word on Sportec's plans to offer their gear stateside?

Regards,

Brian

NotTwinTurboYet

Hello Jeremy,

I agree with Adrian, and to add some more comments, and after experiencing it myself, I would not go for 18" wheels without modifications to the suspensions. You're right when saying that stock suspensions can't handle such heavy wheels. Moreover, I'm sure that you'll lower the car to have the perfect look, and there starts the problem...
If I say that, it's because I already tested it. Bought some 18" GT3 wheels, then shorter springs, and... the rebound was soooooo bad! Moreover it was rubbing everywhere on the front wheels. Finally I chose a Gemballa kit (which is in fact H&R springs + Bilstein sport dampers), and then it became perfect!

One more informations, is that the old 17" cup design wheels are so heavy that modern 18" wheels would not weight much more... I'll try to weight my 18" GT3 wheels and compare to the stock 17" cup.

Ruf wheels are heavy but they are strong, this is a big advantage if you go on a track...

A+

Adrian

Dear Brian,
Was not my idea however I decided it was worth a try. Sportec are working hard to get all their bottles in a line for the US launch of their products. I believe all is progressing well but as you know setting up any business especially from a foreign source takes time.

General comments:
Everyone should remember that the wheel and tyre overall diameter does not change. As the physical wheel diameter increases so you get less tyre to fit around it. In Switzerland it turns out you are only allowed a 2% change in overall diameter.
The 19 inch wheel and tyres are actually lighter than the 17 inch they replaced.
Again I must stress that this experiment only applies to Sportec designed wheels and nothing else.
Some rub issues have come up on the C4 especially on the front and need to be dealt with.
Be very aware that static fitting and checking is only step 1. Step 2 is dynamic testing and this is where the set up of each individual 964 will play a role. Body roll over wider wheels during hard cornering for instance needs to be tested under many different conditions. The type, set up and condition of the suspension components is a major player and the single biggest issue to work out before making recommendations.
A 964 Carrera RS, seriously lowered is also being tested.
Ciao,
Adrian
964C4
GT-2

nine64

does any one know how much the Ruf 18" weight?