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Tyres not retaining pressure

nickjonesn4

Well-known member
Joined
10 Aug 2017
Messages
992
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!
 
Have you not squirted some soapy water on them? How quick are they losing pressure?
 
alex yates said:
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 :thumb:
 
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.
 
cableguy said:
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.
 
Its the valves on both wheels. Seem to only be able to hold 20psi.of pressure without leaking. Being replaced tomorrow.
 

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