18 inch wheels on RS America

[robofc]

Hi,

Is there a problem using 8 and 9.5 x 18 wheels on a 964 narrow body?

[pantera]

Those widths should not be a problem. I'm running 8.5 and 10x18 on my NB 964 C2. Just as important as widths, what size tires will you be running and what are the offsets (ET) ?

Dan

[jpachard]

No, I run 8.5F 10R 18's without issue as well. As pantera said, it depends a bit on your offset, tyre choice and ride height.

I run Michelin PS Cups on mine 235/40F and 265/35 rear.

Cheers, James

[964TargaC2]

Adrian Streather says 18s are a no go on the 964 and he knows more about these cars than most..in fact I believe you could safely say he wrote the book on them :-)

I believe Porsche Issued a TSB stating 18s were OK if the steering rack brace was upgraded to the 993...Porsche is on backorder for those but there is a guy on Rennlist making them (Porsche list is $81 )

[jpachard]

Originally Posted by 964TargaC2

Adrian Streather says 18s are a no go on the 964 and he knows more about these cars than most..in fact I believe you could safely say he wrote the book on them :-)

I believe Porsche Issued a TSB stating 18s were OK if the steering rack brace was upgraded to the 993...Porsche is on backorder for those but there is a guy on Rennlist making them (Porsche list is $81 )

This is old data, Porsche factory ran 18's on the 964 Cup cars for years with no issue. Numerous Cup and RS spec cars are run in the Club Racing circuit here too on 18 R compound and slicks with no issues as well.

Cheers, James

[robofc]

I was thinking of Fikse 8 and 9.5

225/40/18 ET 50

265/35/18 ET 57

[jpachard]

What tires are you planning on running? Those offsets sound right but double check them with Fikse.

[9XI]

My RSA came with 18s. They fit fine with spacers. However, the steering was very heavy. RSAs have no power steering and the 17s were made for that car. I put the correct 17s back on the car, the steering became very managable and the handling improved instantly. I think 18s are a bad idea. I generally don't second-guess the Porsche engineers. They seem to know what they are doing.

[jpachard]

Originally Posted by 9XI

My RSA came with 18s. They fit fine with spacers. However, the steering was very heavy. RSAs have no power steering and the 17s were made for that car. I put the correct 17s back on the car, the steering became very managable and the handling improved instantly. I think 18s are a bad idea. I generally don't second-guess the Porsche engineers. They seem to know what they are doing.

Yes, many RSA race cars run the Porsche Cup electric power steering units for this reason. Why Porsche deleted the power steering on the 964 RSA is beyond me.

As I said before, if performance is what you are after, go look at the folks who race these cars, everyone now runs 18's.

Plus in some brands, tires in 17" sizes are unavailable, Michelin PS Cups come to mind.

Driving on the street is a whole other topic. There 17's are a good choice.

Cheers, James