Red Flash

Hi All

So I am thinking on putting ROW club sports on my 90 GT. I am hoping somebody can give me some feedback on some questions/musings I have...

1.) I have found the needed RDK sensors (used) form the front rim versions of the D90s. I see no need to pump rear tires up to 40psi now the ZR rated tires are available. So, I want to run 35lbs at all four corners. I end up wearing the rear tires simply faster than needed with over pressure it seems.

2.) Then come the sizes. Should I go for 8" and 9" combo with stock tire sizes, or put 9" tires on all corners with the rear tire sizes? Since the offset is 60mm, this means that the front tires would stick out rather far. Nonetheless, I have heard about people that run 9" wheels on all four corners. No, I am not really thinking to go wider than the stock rear tire sizes.

3.) Finally what tires should I use? In Europe the Continental Sport Contacts would be available in both front and re-sizes. What is available in the US? Do I have import tires now from Europe for these strange rims?

Ok, so I hope I don't bore people with another thread about rims and tires... If anybody, Roger should be at least happy to read such a thread, because I am buying a lot of parts from him... And this will be no cheap project.

John

FredR

As I recall, if you are referring the mag alloy wheels, to my memory they are 8 inch x16xET60 all round.

When fitted at the front they will take a 245x45 section same as the rear without rubbing but will probably make the car a bit tail endish.

Regards

Fred

Red Flash

Thanks Fred, I guess the full description of them is "Club Sport Forged Magnesium Alloy ROW." I really was of the opinion that they were 8" in fornt and 9" in back... But, maybe some expert here will correct me...

Bertrand Daoust

As per the Registry, the Club Sport (M393) are indeed 8" front and 9" rear. Both 60 mm offset.

http://www.928registry.org/928%20Reg...928-wheels.htm

FredR

I am not at all sure about the rears- I remember my friends had 245 fitted front and rear.If they are 9 inch rears you might be able to find a wider section to compliment a 245 up front. Just remember 16 inch sections are getting harder to source compared to 17 and 18 inch sections.

The 245 up front fills the wheel well nicely- does not stick out at all.

Regards

Fred

Red Flash

Fred, this is actually what I am also interested to know. The current rims on my car do not look like they have the right offsets, the tires stick out too far, and the rims were supposed to be made for the car...

Chalkboss

Some more info... My 87 has 7 inch (65mm offset) front and 9 inch (60mm offset) rear. 225s up front and 245s in the rear.

FredR

Don,

Those wheels must be Design 90's- are they from a 964? Not so sure I would want a 225 on a 7 inch rim- must be on the margins of technical acceptability- I seem to remember early 928's with phone dials ran a 205 section on 7 inch rims- edit- Tirerack indicates they are fine!

Was the Design 90 an option for 928's in those days?

Regards

Fred

PHIL928

There is a big difference between the club sport D90s and the standard D90s

The Porsche D90 are 7" fronts and 8" rears. With offsets in the 50s, which would explain your wheel situation.

The 928 GT or CS rims are 8" fronts and 9" rears and offsets in the 60s.

They look noticeably different when you have them side by side.

FredR

Phil,

Design 90 is the design pattern. The Club sports were Mag alloy [much lighter], the GT version were cast alloy. Design 90's were also fitted to 911's [964?] and that I believe is where the 7 inch fronts come from.

Fred

Bertrand Daoust

The D90 on my car are 7.5" front with 65mm offset and 9" rear with 52.3 mm offset.

Fred, I think they were an option on my car as the regular wheels were flat disk for the S4 in '91.
The D90 were stock on the GT I think.

Chalkboss

Fred, the wheels were on the car when I bought it, but they were factory Club Sports from Wheel Enhancements. I guess these would be the D90 Club Sports then, although 7" on the front not 8.

FredR

Bertrand,

I believe Design 90 could be ordered as an option on the S4.

Regards

Fred

Red Flash

Don, nice looking car. The color combo and no rub strips are nice.

Just to clarify here, I know what wheels I am looking, and they are NOT D90s. I have a set of D90s that I scrapped for the RDK sensors, becuase the wheels at some very bad curb rash.

The wheels in question here are ROW club sports that have RDK. They look similar to what Don has on his car. But, Don's wheels probably don't have the holes or sensors for RDK.

Rob Edwards

Proper 928-specific clubsports are 8x16 ET 60 in front, 9x16 ET60 in back.
Part #s are 928 362 117 30 and 928 362 119 30, respectively.

The 9x16's are easier to find, as I think they were shared by '88 944's with the M030 option and '89 944 Turbo S's.


A 7x16 ET 65 Clubsport wheel is from the front of '88 M030 and '89 944 Turbo S's, while a 7x16 ET 55 clubsport is for the 944S2.



RE: the RDK sensors, I'm confused- you have a set of ROW clubsports that have sensors in them? Or just a set of bare ROW clubsports that need sensors and you're transplanting sensors from your D90's to plug the holes?

The easiest solution is to fill the sensor holes with whatever sensors you have, and jumper the RDK brain between pins 2 and 13, then check your tire pressurs regularly, because you are a 99th percentile 928 owner.

If you want the system to actually work, at some point they went from 2.5 bar sensors in front and 3.0 bar in the rear, to 2.5 bar all around. May have been with the introduction of the '92 GTS in ROW, not sure. Anyway, you could find some more 2.5 bar sensors.

RE: tire sizes, even with 60 mm of offset on an 8" rim, you're hard pressed to do anything more than a 235, and you'd better have your ride heights close to stock.

RE: tire selection, Tire Rack apparently has the Bridgestone RE-11's in stock right now. Call now, operators are standing by!

If you need the tools for tightening and/or removing sensors, holler and I'll mail you mine.



Obligatory pics:

2.5 bar sensor:



2.5 (tan) and 3 (black) bar sensors:



928-specific 8" CS front rim part and offset #'s






RDK sensor holes:



RDK bypass: