GT3 Wheels

[dave993cars]

Hi all
I have 18" GT3 wheels on my 944S, my problem is they look great IMHO but on Scottish roads they tramline, and I now have a hankering for 17" Cup 1s. I have never driven a 944 with 17" wheels and I am afraid I will have the same problem when driving them on the local roads. All help greatfully received.

Dave S

 

[sawood12]

I have no tramlining problems on my 17" wheels. I think the experience on this forum is that wheel alignment, condition of strut top mounts, castor mounts and tyres can all effect tramlining to varying degrees. Assuming your wheel alignment is OK you could try fitting 968 castor mounts- only costs about £60 and you can do yourself in an hour and is a good mod whether you are suffering from tramlining or not. There are a couple of people on this forum with 18" wheels so they might be able to offer further advice on how they run if you want to keep the 18" rims.

Cup 1's are pretty rare I understand but i'm sure I saw a set on ebay a few days ago.

 

[Guest]

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=8039594505&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

Saw them too... 1 day left I think and currently at £205. Seems cheap?

 

[dave993cars]

Hi Andrew
I thought with Perelli P Zero Asimmetrico tyres combined with the GT3 Wheels I would not have the problem with transference of vibration to the suspension, and while looking at previous posts the fitting of 968 Castor mounts does not guarantee you won't have tramlining, so unless I spend a lot of money I should still be concerned about 17" cups. ?

regards

Dave S

 

[Guest]

i considered the Cup1's on ebay, but they need a refurb and i'm fairly sure they're not geniune Porsche wheels. and you can bet your a**e that they'll end up going for a few pounds more than they're worth

 

[idwoodvale]

Dave,
I have 17" Cup 3 (replica) with Pirelli P-Zero Asymmetricos on my Lux with Koni shocks and get a fair degree of tramlining on certain roads. Don't know the state of my castor mounts though. May be time to get the 968 ones.

 

[mik_ok]

Those Cups1's on ebay look to be in good nick. It appears to be a set of four 7.5x17 though, so not much use for a 944 which needs the 9" rears. Doesn't mention offsets either (could be early 911 offsets which are no use) and I can't tell from the pics if they are genuine or copies (and speaking personally copies wouldn't bother me in the slightest - they are worth less however).

Given that others run 18"s without major probs, your car shouldn't in theory be too bad for tramlining. Whilst I think the GT3 wheels look awesome (there was often an S2 with them parked round the corner from Glasgow OPC a while back - one of the mechanics cars?) they aren't a common fitment. What offsets are the fronts?

I'd suggest 2 things.
1. Fit the 968 castor mounts. It really is an easy job, and only £80-odds for the parts.
2. Get a front geometry alignment at Motortune in Shotts. Costs 1hr labour £35+vat. During this Peter will notice whether anything else is amiss (with steering rod, balljoints, track rod ends, front wishbone bushes etc).

Both of these should help significantly for notalotacash, although if your geometry is found to be out, you may need a new set of front boots before you really notice the difference. Unfortunately the latter point only becme clear to me recently, when I finally banished my tramlining (and that's on std 16" Design90s).[]

 

[Fen]

I agree with mik - there need be no tramlining with 18's if the offset is correct. Tell us the width and offset and we can comment if it is within a range we know to work.

To expand on the tyres question it isn't so much about type as wear. mik just replaced tramlining 16" Yoko AVS (I think?) tyres with similar sized Toyos and the car is transformed. I had the same model Yokos on my 18's when they were new and they were perfect. I think if the alignment is out for a period it can cause uneven wear or even damage to the tyre construction that renders the tyre useless regardless of later geometry re-setting. Clearly it's a risky option from an expense point of view to replace apparently good 18" tyres, but if your geometry, rim width and offset are right, you have 968 castors and your suspension is otherwise in good condition then you should not have tramlining with 18's. The 968 castors are optional, but realistically the original 944 ones will be knackered by now and will allow movement and the 968 ones are both better and cheaper.

 

[dave993cars]

Hi guys

Mik- I will check the offset to night of the front wheels and let you know, more immediate, I have been offered Cup 1 replicas 7.5J ET 52 and 9J ET 47 will thease fit my 944S (255/40 and 225/45)

Dave s

 

[mik_ok]

They sound correct sir. []

 

[dave993cars]

Hi Guys

Mik- the GT3 wheels are 7.5J front ET50 9J rear ET52 purchased from Jasmin. where can I purchase the 968 castors.


Dave S

 

[Fen]

They shouldn't tramline. 968 castors from an OPC - may I suggest Adrian Oxley at Exeter 01392 822841 as the OPC parts man of choice (he'll post).

 

[Big Dave]

Just to throw my 2pth in..
I had a set of 18" sport classics fitted to my 968 cabrio last year....
It drove horribly.. It had new 968 castors + new arb bushes at the front .
I took them off + sold them...
The car looked GREAT ,,,,, BUT drove like a dog...Followed potholes + ruts all over the place....You realy had to concentrate whilst driving it....
Although ,, it could well be that its a cab + slightly more "flex" in the shell...
Ive actually bought a set of the 996 Carrera 18" [Aniversary POLISHED ] 5 spokes to put on the cabrio ,, BUT im having second thoughts....[8|][8|][8|][8|] Could be up for sale "soon"......

 

[Fen]

I think it's a lot to do with the cab shell. They are extremely flexible compared to the coupe an mine was a bit of a pig on 18's too. I'm really not a fan of those anniversary polished rims, so for what it's worth I'd sell them if I were you. Too bling.

 

[mik_ok]

Dave. As per Fen - nothing wrong with the offsets.

I got my castor mounts from my local OPC (Sytners Glasgow are very close). As fen has pointed out - you may be better getting them posted from Adrian - I've never used him but I understand his prices and service are excellent.

Read THIS to see how easy they are to fit. (the first two pages are banter and general slavering ~ don't actually fit them 'til page 3 [] )

If you are remotely uncertain, and are anywhere near Shotts, Peter at Motortune would stick them on whilst doing a geo adjustment, and I'm certain it wouldn't cost you much extra.

 

[Mikie_gb]

I have 18inch Turbo cups and after changing tyres to Pilot Sports (from well thrashed Pirellis) I have no tramlining on a standard 944S set up. I haven't had the alignment checked and I will assume that the castor blocks et al are the same age as the car. I will look to replace the dampers all round as the ultra low profile tyres have no flex, tons of grip and highlight body roll on aggresive high speed sweeps. ( aggresive and bumpy enough to have the usually silent interior creaking and groaning all over the place and passengers eyes and jaw firmly clamped shut).

The biggest draw back I have with the massive tyres are that on a smooth surface the car is silent, more so than on the std 15", but on concrete or other high grip surfaces, the noise is mind shattering.

 

[sawood12]

I think the issue with the Cabrio's is probably down to body flex. I've read with interest over on the Boxter forum that alot of people are very dissapointed with their PASM equipped Boxters as the system obviously requires a stiffer set-up to work from. Alot of them are wishing they specc'd the passive sports suspention option instead.

In any case I don't think anyone is saying that the castor mounts is causing problems with tramlining but they might be able to help or improve the situation. I suspect the causes of tramlining is probably a combination of several things which is why no-one can provide a difinitive answer as it's different in every case. As I said before 968 mounts are a good mod worth considering by everyone regardless of tramlining issues. They are simply a better designed mount.

 

[pae]

ORIGINAL: matt951

i considered the Cup1's on ebay, but they need a refurb and i'm fairly sure they're not geniune Porsche wheels. and you can bet your a**e that they'll end up going for a few pounds more than they're worth

Went for £390.

Phil

 

[dave993cars]

Guess what Phil I got them[] only time will tell if they were a good deal or not, as said early on they seem to be the right size and offset, and if the 968 castors don't help the GT3s, I will have my Cup 1s to try. Jasmin wanted £600+VAT for the same type wheels.

Dave S

 

[mik_ok]

The ad looked like four 7.5x17" [&:] ~ I take it two of them are 9" width after all then?

For Info ~ ESS offer new 17" Mille Miglia Cup1 for £499+ vat (£586-odds).