Re: Tyre pressure lose
 

had a simular problem mine was loosing it after riting at speed on the motoway, tyre place tracked it down to caps told me it was down to centalfudrick force (sorry cant spell that) anyway caps was changed problem solved oh by the way had metal ones they changed them to normal plastic ones

Re: Tyre pressure loss?
 

Nah, teriyaki is right. The valve does the sealing not the valve cap. The cap is there to keep cr*p out.

If the valves are faulty just replace them with good ones. Its a bout a 5 minute job in a tyre garage (that includes making a cuppa).

Re: Tyre pressure loss?
 

Took bike to tyre place , they took wheel off and tested in water bath for leaks , no leaks , replaced tyre values . still leaking about 1-2 psi a day ...
Never has this kind of problem with a tyre before
Rear storm has about 4.5k & is about half worn , don't want to replace tyre yet , thinking about trying some ultra seal tyre stuff any one got any ideas ?
cheers

Re: Tyre pressure loss?
 

Did they replace the valve stem too or just the valve core? Leaks around the base of the stem or the tyre bead are also a common cause of slow (undetectable) leaks.

Cheers

Re: Tyre pressure loss?
 

Also, next time the tyre is off, try to get a peek at the rim. The rim might need a thorough clean.
Some tyre fitters (at least in my part of the world) tend to use soap flakes (Lux laundry soap with enough water to make it a mush - they call it elephant c**) which contains a small amount of free caustic. The caustic causes corrosion problems between tyre & bead on ally wheels and ultimately leaks.

Cheers

Re: Tyre pressure loss?
 

Good morning all.

The loss of a couple of PSI per week is normal. Hence checking ones tyre pressures weekly or every 200 miles is a good idea.
Obviously tyres & wheels are made to tolerances, & it is possible to get a wheel/tyre combination where each are at opposite ends of their specified tolerance, then the loss is normally greater.

Another thing is that contributes to pressure loss, is when there's a build up of dried 'gunk' on the inside of the wheel rims, left over from previous tyres. It's not a bad idea when having new tyres fitted, to ask the fitter to give your rims a good brushing to remove the aforementioned 'gunk'.

As said, check your pressures weekly, or every 200 miles.


Cheers.

Re: Tyre pressure loss?
 

Just the valve stem , if valve core was leaking would this not show when totally emerged in water ?
My bike could described as a bit gunky

The rear has been on for 3 months & 4500 K miles and never really lost much pressure on weekly check occasional 1psi , now loses 1-2 psi a day ?

Thanks for the replies

Cheers Steveg

Re: Tyre pressure loss?
 

Hmmm... don't know if we are on the same page
Valve Stem = the bit that goes into the rim and the valve core screws into.
Valve Core = the guts of the valve and screws into the stem.

Anyway... Some leaks (like 1-2psi) can be damned near undetectable, so the answer to your question is "no".

There is an alternative solution, but I am loathe to suggest it... I hate the stuff for the mess that it makes of everything (I change my own tyres) but a small amount of slime (or some similar product) will cure it. FWIW, I reckon this type of leak is the best use for such products.

Cheers

Re: Tyre pressure loss?
 

Hi ,

It was the valve core that was replaced , will see how it goes as I do a fair amount of miles , tyre should be replaced with another couple of months so might live with it , if not drop some ultra seal it it.

thanks for the replies

Cheers Steve

Re: Tyre pressure loss?
 

if you suspect the valve is at fault get yourself some washing up liquid plastered around and in it. If you have a pump inflate the tyre higher than normal, say 40/45 psi and watch.

If you have a leak, even slight then it should show up over the course of a cuppa. Otherwise I think its SpannerMans suggestion of crap around the rim where the tyre is mounted. Only way to resolve that is to remove, clean and remount it.

I wouldnt go squirting any ultra seal around unless its an emergency get you home or you'll end up with a worse mess to clean up.