alanmac Posted September 3, 2010 Share Posted September 3, 2010 Just had new tyre fitted and assumed my valves were metal. Garage said they do not fit metal valves but would change the "core" ? The new tyre valve looks similar to others but different enough to raise my doubts. I will be returning to garage next week sometime to confirm all OK but can anyone tell me how I can identify metal from "ordinary" valves please. I would like to be armed with information before I go bacvk. Thanks Link to comment Share on other sites More sharing options...
silverback Posted September 3, 2010 Share Posted September 3, 2010 hi Alanmac look at this previous posting by me http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=19434&posts=9 basically metal look metal, ordinary are rubber looking with a nut holding them against the rim metal can be reused every time you change the tyre hope this helps jonathan Link to comment Share on other sites More sharing options...
lennyhb Posted September 3, 2010 Share Posted September 3, 2010 Not all high pressure valves are the steel ones you can get rubber ones with a brass insert, these look similar to the rubber ones except you can see the brass core extending past the rubber outer. Posting from the Massif Central in France a nice pleasant 34 deg. today. Link to comment Share on other sites More sharing options...
silverback Posted September 3, 2010 Share Posted September 3, 2010 yes i stand corrected lenny, posting from west yorkshire, 7 degrees but at least its not raining!!and weve had a good week 20 degrees no rain but ive been indoors working :'( jonathan Link to comment Share on other sites More sharing options...
Brambles Posted September 4, 2010 Share Posted September 4, 2010 alanmac - 2010-09-03 8:18 PM Just had new tyre fitted and assumed my valves were metal. Garage said they do not fit metal valves but would change the "core" ? The new tyre valve looks similar to others but different enough to raise my doubts. I will be returning to garage next week sometime to confirm all OK but can anyone tell me how I can identify metal from "ordinary" valves please. I would like to be armed with information before I go bacvk. Thanks If he has just change the core then the valve body is the same as before. Are you sure he has not just given it a wipe clean, or possibly just has a different valve dust cap. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 4, 2010 Share Posted September 4, 2010 Most vehicle tyre-valves are the "snap-in" type. These are flexible with a rubber body and a brass-tube centre. They are pulled through the valve-hole in the wheel-rim and the rubber body ‘snaps’ against the wheel-rim to form a seal. They are available in ‘standard’ or ‘high pressure’ formats, with (speaking generally) the former designed for pressures up to 4.5bar (65psi) and the latter for pressures up to 7.0bar (100psi). Although it’s probably the case (as lennyhb suggests) that every high pressure snap-in valve will have its centre tube well exposed above its rubber body, not all snap-in valves with exposed centres are high-pressure ones. Snap-in valves are normally removed and replaced with a brand-new valve when a tyre is changed. Clamp-in (or “metal”) valves are rigid, made from brass and normally nickel plated. They are inserted through the wheel-rim valve-hole from the inside and clamped in position via an external nut. Sealing at the wheel-rim hole may involve an O-ring or a flexible washer. Clamp-in valves are normally capable of handling pressures up to 14bar (200psi). Standard practice within the UK tyre-fitting trade seems to be to replace just the ‘core’ (ie. the small assembly that screws into a valve’s centre tube to form a seal) of a clamp-in valve when a tyre is changed. I suspect valve manufacturers would advise that, each time a tyre is changed, the seal of a clamp-in valve (or the complete valve) is also replaced. Snag is that clamp-in valves are relatively uncommon and there appears to be no standardization of valve or seal design, so tyre fitting firms won’t normally hold valves or seals in stock. That’s basically why they just change the core. This type of valve also needs a lot more care when fitting, as over-tightening the clamping-nut can harm the seal. For examples of ‘cores’ and various valve types, see the following pages on the Alligator website: http://www.alligator-ventilfabrik.de/index.php?Valves_cores http://www.alligator-ventilfabrik.de/index.php?Passenger_car_Snap-In_valves http://www.alligator-ventilfabrik.de/index.php?Passenger_car_metal_valves Link to comment Share on other sites More sharing options...
alanmac Posted September 7, 2010 Author Share Posted September 7, 2010 Thanks one and all for your help and info I am better informed. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.