Joined: 10 Aug 2017 Posts: 248 Location: Edinburgh
Posted: Tue Jan 09, 2018 9:48 pm Post subject: Tyres not retaining pressure
Hi All,
I recently put some 18" wheels on my 993. They are in very good condition and they came (2nd hand) with barely used Michelin PS4s. Both the front and rear wheels were not holding tyre pressure so I had a tyre fitter look at them and he identified that slilicon rather than rubber had been used round the edge of the rim. He re-fitted and used lots of rubber to make a good seal. The situation now is
Rear wheels - holding tyre pressure perfectly
Front wheels - will inflate and the lose pressue to 20PSI on both wheels
It looks as if different metal/chromed valves have been fitted not the rubber ones. Could this be the problem? My theory is that the valves can only hold 20 PSI of pressure but this may be total BS!! There are no punctures in the tyres 100% sure of that
help! _________________ 1996 Carrera 2S Vesuvius Metallic
2016 Golf R
2005 E55K Wagon
alex yates Donnington
Joined: 06 Mar 2014 Posts: 12815 Location: The Ribble Valley, Lancashire
Have you not squirted some soapy water on them? How quick are they losing pressure? _________________ 2000 Manual 996 C4 Arctic Silver Convertible
Used daily....rain, sun or snow.
nickjonesn4 Monza
Joined: 10 Aug 2017 Posts: 248 Location: Edinburgh
Posted: Tue Jan 09, 2018 11:34 pm Post subject:
alex yates wrote:
Have you not squirted some soapy water on them? How quick are they losing pressure?
Very slowly! Takes maybe 2 days to go from 36 to 20psi where they stay.
I will give the soapy water trick a try. Don't know why I didn't think of that _________________ 1996 Carrera 2S Vesuvius Metallic
2016 Golf R
2005 E55K Wagon
cableguy Albert Park
Joined: 10 Sep 2007 Posts: 1514 Location: North Yorkshire
Posted: Tue Jan 09, 2018 11:56 pm Post subject:
Quite common on 3 Piece Rims if not sealed correctly. I'm not sure on Work Rims, however Speedlines have a crush ring and rubber seal between the barrel, face & lip. If these are not in perfect condition then air can slowly escape. Obviously the fixings need to be torqued to the correct figure. Most professional rebuilders will add a specific wheel mastic to ensure a perfect seal.
It could also be the valves if not fitted correctly and as mentioned above, submerge in water which should show any leaks.
C. _________________ Pork!
nickjonesn4 Monza
Joined: 10 Aug 2017 Posts: 248 Location: Edinburgh
Posted: Wed Jan 10, 2018 8:31 am Post subject:
cableguy wrote:
Quite common on 3 Piece Rims if not sealed correctly. I'm not sure on Work Rims, however Speedlines have a crush ring and rubber seal between the barrel, face & lip. If these are not in perfect condition then air can slowly escape. Obviously the fixings need to be torqued to the correct figure. Most professional rebuilders will add a specific wheel mastic to ensure a perfect seal.
It could also be the valves if not fitted correctly and as mentioned above, submerge in water which should show any leaks.
C.
Thanks Carl. I will double check with the guy who did my wheels but I do know that he looked up and used the correct Torque on the fixings. Seems odd that the rears are totally fine.
Will report back. _________________ 1996 Carrera 2S Vesuvius Metallic
2016 Golf R
2005 E55K Wagon
nickjonesn4 Monza
Joined: 10 Aug 2017 Posts: 248 Location: Edinburgh
Posted: Thu Jan 11, 2018 10:00 pm Post subject:
Its the valves on both wheels. Seem to only be able to hold 20psi.of pressure without leaking. Being replaced tomorrow. _________________ 1996 Carrera 2S Vesuvius Metallic
2016 Golf R
2005 E55K Wagon
cableguy Albert Park
Joined: 10 Sep 2007 Posts: 1514 Location: North Yorkshire
Posted: Thu Jan 11, 2018 10:16 pm Post subject:
Good result, saves splitting the rims.
C. _________________ Pork!
nickjonesn4 Monza
Joined: 10 Aug 2017 Posts: 248 Location: Edinburgh
Posted: Thu Jan 11, 2018 10:54 pm Post subject:
cableguy wrote:
Good result, saves splitting the rims.
C.
Absolutely! _________________ 1996 Carrera 2S Vesuvius Metallic
2016 Golf R
2005 E55K Wagon
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