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| tyre pressures https://forums.tipec.net/viewtopic.php?f=25&t=2056 |
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| Author: | garylane [ Thu Oct 30, 2008 12:56 pm ] |
| Post subject: | tyre pressures |
Hi, I'm running 19" wheels on my 89 944 turbo running on 265/30/19 and 235/35/19 tyres. On top of this I've got mo30 suspension and drive on horrible bumpy roads in the UK. The car does seem to tram line alot and seems a bit unstable at high speeds.  Has any one got any ideas how I can make this a little better with out going back to smaller wheels, ie tyre pessures etc. With thanks Gary
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| Author: | 944 Man [ Thu Oct 30, 2008 1:03 pm ] |
| Post subject: | Re: tyre pressures |
You have badly mismatched tyre sizes on overly large wheels: tyre pressures arent going to rectify that Im afraid. |
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| Author: | Li Moo Bai [ Thu Oct 30, 2008 1:11 pm ] |
| Post subject: | Re: tyre pressures |
19" wheels?!  can't see them even fitting under the 944 arches? what's wrong with 16s or 17s? |
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| Author: | garylane [ Thu Oct 30, 2008 2:12 pm ] |
| Post subject: | Re: tyre pressures |
Just to clarify the 265/30/19's are on the back with the 235/35/19's on the front. All tyres are brand new (Falken 452) as are the wheels, and were fully balanced before fitting to the car, and yes they fit under the arches just fine with no rubbing! |
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| Author: | 944 Man [ Thu Oct 30, 2008 2:52 pm ] |
| Post subject: | Re: tyre pressures |
None of that alters the fact that the wheels and tyres are completely unsuitable for the car. The car was designed to run on 16" wheels and you can get away with 17"s; anything more just wont work properly. Added to that, that M030 suspension isnt particularly brilliant and its likely to be worn out by now: fitting the 265s to the front probably wouldnt make it a deal worse..... |
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| Author: | JW590 [ Thu Oct 30, 2008 2:57 pm ] |
| Post subject: | Re: tyre pressures |
Did you take advice before making such a drastic change to the set up that Porsche thought was quite good for your car? Failing that, have you considered asking whoever sold you the wheels / tyres for some advice? There's too many out there will just sell for profit, and it's not their problem when you go back. My son-in-law's Alfa Spider had fancy big wheels on it when he bought it. It looked fantastic. They're stacked up behind the shed now doing nothing, for the very same reasons you have given, and Alfa originals are back on the car giving a good ride. Unfortunately, I would think that the only way to get what you want - which I suspect is nice looks and a decent ride - is to go back to an original Porsche size. Lowering profiles will always give a harder ride because the sidewalls provide some cushioning against UK roads. |
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| Author: | garylane [ Thu Oct 30, 2008 3:32 pm ] | ||
| Post subject: | Re: tyre pressures | ||
The wheels are Victor equipment which I am sure you will all know are only designed for Porsche's. On seeking advice from the manufacturer I was advised to go for the 19's and was told there are people in America running on 20's. The car only tramlines on roads that even my 16" wheels tramline on, but on nice flat roads it runs perfect if not better. Please bear in mind when Porsche designed the 944 even 17" wheels were not invented. I am only seeking advice on tyre pressures, and the suspension has been overhauled using 968 bushes and is running totally fine.
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| Author: | Sean Smallman [ Thu Oct 30, 2008 3:36 pm ] |
| Post subject: | Re: tyre pressures |
Have to agree with everyone else, I had 18" GT3 rims on mine and the cab looked lovely but the ride was bloody lousy. Now running on stock wheels and the car is able to be driven much more quickly. |
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| Author: | garylane [ Thu Oct 30, 2008 3:37 pm ] |
| Post subject: | Re: tyre pressures |
The ride isnt a problem, in fact really doesnt seem a lot harder than with the 16" wheels, it is the tramlining that I am trying to cure which as previously mentioned happens with the 16" wheels. |
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| Author: | tr7v8 [ Thu Oct 30, 2008 3:38 pm ] |
| Post subject: | Re: tyre pressures |
To a certain extent I agree with what John has said, although every car manufacturer designs around what is available AT THE TIME not because it's the most suitable. Look at early 944's that run on 15" but decent tyres are now very expensive so a lot of people have gone to D90's to get cheapish 16" tyres, with a decent range. Technically Porsche say don't fit bigger than 17" & they only allow 17" on late 944's & after 968 Castor mounts & a geometry change. Detailed in the works manual. Possible that your insurance could be voided if your company thought it an issue. A lot of people run 18" to get the 928 brakes & they put up with the tramlining & harsh ride. Not sure you'd ever get 19" under control & the ride will be dire. |
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| Author: | tr7v8 [ Thu Oct 30, 2008 3:52 pm ] |
| Post subject: | Re: tyre pressures |
Just to add to the above as Gary posted at the same time as me. Were the front struts replaced when it was rebuilt? And what was the geometry set to? My ARO had high speed instability & it turned out that the front strut had a massive amount of play where the piston rod enters it. What with this, old hard tyres & completely knackered rear shocks, plus the geometrywas all over the place made it a white knuckle thing to drive.... |
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| Author: | garylane [ Thu Oct 30, 2008 3:59 pm ] |
| Post subject: | Re: tyre pressures |
Thanks for the replies. I have just put on the 16" wheels and taken it for a drive, but alas, it still tramlines down the same bit of road that it tramlined on before. Before any suggests the suspension, geometry etc I have just had it checked at Promax who gave the suspension a clean bill of health and incidently also sell 19" wheels for the 944. My friend on the BMW forum said his car also tramlines down this particular piece of road and suggested not driving along it anymore, what would you suggest? 
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| Author: | 944 Man [ Thu Oct 30, 2008 4:01 pm ] |
| Post subject: | Re: tyre pressures |
garylane wrote: The wheels are Victor equipment which I am sure you will all know are only designed for Porshce's. On seeking advice from the manufacture I was advised to go for the 19's and was told there are people in America running on 20's. The car only tramlines on roads that even my 16" wheels tramline on, but on nice flat roads it runs perfect if not better. Please bear in mind when Porsche designed the 944 even 17" wheels were not invented. I am only seeking advice on tyre pressures, and the suspension has been overhauled using 968 bushes and is running totally fine. Youre refusing to accept what youre being told. They make look pleasant enough but theyre totally unsuitable for your car (irrespective of whether theyre made for a Porsche). Most 993s cant run on 18" wheels and your car will not drive well on ridiculous 19" wheels; no matter what you do with the tyre pressures. |
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| Author: | 944 Man [ Thu Oct 30, 2008 4:08 pm ] |
| Post subject: | Re: tyre pressures |
What width wheels are you using and what is the offset of each pair? |
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| Author: | garylane [ Thu Oct 30, 2008 4:08 pm ] |
| Post subject: | Re: tyre pressures |
Quote: Youre refusing to accept what youre being told. Sorry 944man, my mum is now sending this 40 year old man to bed with no broth. p.s. how do you get you walking frame into the back of the 944? 
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