Wheel and tyre sizes/off-sets

[rjs993]

I am thinking of changing the standard 17" wheels on my C2S to standard Porsche 18" wheels (as originally fitted to the C2S/C4S). Presumably the 18's will fit without any hicups despite the different width of wheels/tyres? i.e. I believe that the 17" wheels are narrower?

[]

 

[rjs993]

Useful stuff .. thanks Maurice.

I find the 17" a little "bouncy" at the front end and hoped that the 18" may reduce this - although I could experiment with the pressures before making the change I guess. Any suggestions?

You mention the rear offsets but not the front - are the 18" the same as the 17"?

Cheers

Robert

 

[Guest]

Bouncy does sound like shocks. (First thing Dave at JZ said to me when he test drove my car - although as you will see from below it was a bit of a mess by then)

I have a C2S and have just had new front shocks and mounts as mounts were split and drivers shock was weaping and then exploded on a unmarked/un ramped road surface change on a dual carriageway.

I had all my work done by JZ Machtech in Herts. I also enquired about upgrading the shocks to Bilsteins and they advised it was probably best to stick with the original equipment as if I was going to upgrade shocks I would need to the go all round the car with new springs and shocks (KIT). They had seen cars with only shock upgrades without matching springs and they had been a mess.

I am very happy with the work and results from JZ

My car does have the 18" Turbo wheel but I would definately get the suspension checked before looking at new wheels. As for tyres I am running 285 and 225 ContiSportContact n2 and pretty pleased sofar although do not have a comparison yet. Porsche GB advised these were OE on my car.

Will

 

[James Shunt]

Will

I'd be interested to hear how much JZM quoted you for supplying/fitting the shocks and the kit - I've heard estimates of around $1100 in the US. I've also got the 18in turbo wheels and I may need to do what you've done - hopefully without the exploding problems []. Bad luck on that and I hope it didn't cause too much physical damage in addition to the wallet damage...

I'll second the highly reliable Maurice on this one too because all the views I've read suggest that the Bilsteins are much more hard-wearing than the Monroes.

Thanks

James

 

[rjs993]

Great feedback.

It seems as though I need to check the front shocks before doing anything else - this could also explain the creaking noise when going over speed-bumps and similar - Bilsteins being the best option and a straight swap for the standard issue jobs.

The 18" wheels do look the biz though! So if I am following the plot properly the offsets for 18" wheels on a wide-body car are:

Front: ET52
Rear: ET40

All OK?

Thanks for all the help.

Robert

 

[Guest]

James - JZ costs : (STANDARD EQUIPMENT)

drop links x 2 £48.08 = £96.16
shocks x 2 £227.88 = £455.76
bellows x2 5.87 = £11.74
buffer x 2 10.60 = £21.20
mount top x2 101.02 = £202.04
shock h/nut x2 10.38 = £20.76
brake line x2 £8.58 = £17.16 (easily brake with this work apparently)
brake fluid £10.69
4 wheel alignment £220

£1055.51 x 17.5% = £184.7

PARTS TOTAL inc VAT = £1240.22

Labour @ £45 p/h ex vat

I had some other work done too so not sure exact labout on this job but total all in was 6 hours.

Hope this gives you some guidance.

Will

 

[James Shunt]

I've been away so I haven't had a chance to see this or say thanks all round - this is useful info.

Cheers

James

 

[jcosh]

Hi

I know I'm coming into this thread a little late, but itis now relevant to me.

Have done a couple of track days in my C2S and am pleased with it's performance on standard suspension. However, it would appear it could be improved with better shocks/springs.

Question - Would a set of Bilstein 993 RS Cup dampers be suitable for my car and are they the same items as refered to above?

Reason I ask is a new set are available for sale and I want to check they are the best option for my car. The seller tells me they are the same as those fitted to a 993 RS. I would also need to replace the springs. Any info much appreicated

 

[Guest]

Jonathan

I should my car back on road tyres and with a std interior by the weekend. I'll bring it to the next R23 club night so you can see what it's like with PSS9s on it. BTW cost of PSS9 package is around £1200 plus fitting (and RS bits if you wan them!). From memory the shocks you are talking about are around £700?

Are you going on Sunday to Cornbury House?

 

[jcosh]

Can't make Sunday as it is my daughters Christening.

My car is at Parr today having a re-alignment set up and improved brake fluid. Thought this was a sensible route to take b4 I spend loads on shocks etc.

Am going to Silverstone to do another track day on the 5th, there are still a few places if anybody interested.

CU on the 4th Peter.

 

[jcosh]

Got car back from Parr last week.

Only driven in the wet, but feels fab - less understeer due to more castor on the front. Settings are Parr recommended - not standard.

Much better than when I first had it done by Camtune. Only down side was the price - twice what I paid at camtune!

Off to Silverstone on Weds, so will be able to give better feed back then.

 

[rjs993]

End of the creaking story ... almost!

Well, finally I took my 2S in clutching the printed forum discussion to have my front anti roll bar bushes vasolined. A long discussion ensued about how unlikely this was to be the source of the problem. Various ball-joints were then checked but made no difference to my "creak" (typically over speed-bumps). So, in the end, the anti roll bar bushes were removed (not an entirely simple manouvre!) and the appropriate grease applied (apparently vasoline should not be used on rubber) and hey-presto Maurice was on the button - the problem is completely cured.

Thanks Maurice you are my hero.

Cheers y'all.

Robert

 

[38F3E1]

ORIGINAL: MoC2S

Tyre sizes as per manual - 225/40F, 285/30R. Factory pressures are 36F 44R, but these are generally considered excessive.

Does anybody have a better recomendation on pressures for these tire sizes? I am running those tyre sizes on 2002 18" Carrera 5 spokes (8J front and 10J rear) on my narrow body 993 coupe

Thanks
Ian.