To 17 inches or not to 17 inches? - Page 1 - Porsche General - PistonHeads UK

I assume you mean a 944 S2. You can fit up to 18s, as my friend had his 968 on 993TT wheels. However, there was some wheel arch scrub over speed humps or with people in the back. Be warned, width is the biggest problem, not rolling radius (the tyre height tends to go down as the rim diameter goes up). Also, make sure any wheels you get are the correct offset. 911s have a funny offset compared to the 944, if I remember. Ask someone like Ray at Northway - he will know what fits and always has a few sets of 17s going spare for reasonable dosh. Cheers Domster

thanks! Thom

No probs. My personal favourite are the 964C2 style cup wheels - lovely on a 944! I always had the normal Design 90s (7 spokes) on my S2 Cabriolet and they were a bit dull in comparison. Cheers Dom

According to factory Technical Bulletin #9305 of April 15, 1993 "Retrofitting of 18" wheels on Porsche vehicles which do no have 18" wheels as original equipment is NOT ALLOWED (bold and underlined!). The factory says that endurance tests have shown that equipping certain Porsche vehicles with 18" wheels in an application not already approved by Porsche Cars may result in loosened bolts and/or threaded connections on the front wheel carriers. This, in turn, may cause fractures in these components. Fractures may also occur in the front strut mounts and in the body in the area of the rear suspension as a result of the installation of 18" wheels. Such damage can occur without warning. This bulletin applied to ALL models of cars. Also of interest is Technical Bulletin #9303, September 28, 1993, which deals with the fitting of 17" wheels and tyres to 4-cyl models from 1987 onward, 944, 944S, 944T (all with M30 option), Turbo S 1988, Turbo 1989, and S2 from 1989. Fitting of 17" wheels on vehicles previously equipped with 16" wheels is allowed, however you should also replace the caster adjustment parts so that the alignment can be adjusted for the proper caster angle of 3 deg 15-45'. The parts needed are: Rear Mount 951 341 023 00, 2 each Eccentric 951 341 431 02, 2 each Bolts, 4 each The 951-341-023-00 part has been superseded by the -01 part. There is also a 968 Club Sport part available, 951-341-023-30. The upgraded 951 part is also used on 968. There is a huge difference between it and the stock part. The stock mount has a LOT of rubber and only a thin metal cover around it, like that used on a antiroll bar. The upgraded part has just a thin rubber insert with a substantial metal piece around it. The eccentric bolt is also used as standard on the 968 and I'm told it is serrated to hold the caster setting better. There is a certificate from Porsche (Nov, 15th 1996) which states what additional mods have to be done to the car when upgrading to wider rims/tyres. This certificate lists all (in Germany) allowed tyre mods for all 944 models. When upgrading to 7.5x17,offset 65mm (225/45) and 9x17,offset 55mm (255/40) you also have to install (among other things you have to check): # 951.341.023.01 (rubber bearing) # 951.341.431.02 (eccentric bolt) The listed parts are to be installed at the front suspension, not the rear. When upgrading to 8x17,offset 52mm (225/45) and 9.5x17,offset 68mm (255/40) you have to install the above parts and additionally a 17mm spacer for the rear rims (#951.331.611.02)

Are you sure you really want to? I have 18inch wheels on my Boxster S - original equipment I might add. Tramlining does happen on our crappy roads....

18 inches are out of question but maybe the five-spoke "Porsche 90s classic" 17s... Thom

dmsims - many thanks for the info. It is good to get the party line now and again. I suppose retrofitting any wheel could cause any amount of know and unknown problems, it is for the fitter to be aware. My friend with the 18 inch wheels on his 968 didn't notice any problems during the year he had them on his car, but that is not to say ill effects would not eventually occur. I'm sure some wheel/car combinations work better than others. Cheers Domster

I am toying with the idea of putting my beloved S2 under 17 inches regime... Is there really a great deal of difference between the standards rim? I am no Richard Burns yet so it might be pointless form the efficient side...? Thom