Log in

View Full Version : Tyre deflating - Normal?



StoneChucker
17th February 2005, 16:29
Is loosing 1psi over 8 hours acceptable? Or over a week, between 4 - 5 psi? I keep my bike permanently on the paddock stands (earthquake proofing), would this have any effect? Normally it stays pretty constant, but recently it drops at the above mentioned rate. BUT:

I'm not sure if the time I started keeping it on the paddock stands coincides with the time it started loosing pressure. Also, the front stays constant. The front is NOT on stands, so the difference is that the rear is raised. Can having the tyre raised speed up the pressure loss?

Finally, there should be no adverse effects with keeping the back on the stand constantly when not in use? I'd hate one of the bobbins to pop off, and the bike to take a midnight tumble.

Thanks :confused:

PS: I'm used to my car loosing between 3 and 5 psi per week...

MSTRS
17th February 2005, 16:35
Is loosing 1psi over 8 hours acceptable? Or over a week, between 4 - 5 psi? I keep my bike permanently on the paddock stands (earthquake proofing), would this have any effect? Normally it stays pretty constant, but recently it drops at the above mentioned rate. BUT:

I'm not sure if the time I started keeping it on the paddock stands coincides with the time it started loosing pressure. Also, the front stays constant. The front is NOT on stands, so the difference is that the rear is raised. Can having the tyre raised speed up the pressure loss?

Finally, there should be no adverse effects with keeping the back on the stand constantly when not in use? I'd hate one of the bobbins to pop off, and the bike to take a midnight tumble.

Thanks :confused:

PS: I'm used to my car loosing between 3 and 5 psi per week...I'd be checking that the neighbourhood brats aren't dicking with your valves or something. Pressure should not measurably drop over a month, mush less a week.

**R1**
17th February 2005, 16:38
Is loosing 1psi over 8 hours acceptable? Or over a week, between 4 - 5 psi? I keep my bike permanently on the paddock stands (earthquake proofing), would this have any effect? Normally it stays pretty constant, but recently it drops at the above mentioned rate. BUT:

I'm not sure if the time I started keeping it on the paddock stands coincides with the time it started loosing pressure. Also, the front stays constant. The front is NOT on stands, so the difference is that the rear is raised. Can having the tyre raised speed up the pressure loss?

Finally, there should be no adverse effects with keeping the back on the stand constantly when not in use? I'd hate one of the bobbins to pop off, and the bike to take a midnight tumble.

Thanks :confused:

PS: I'm used to my car loosing between 3 and 5 psi per week...
hhhmmmm not sure if its "normal" but at times i can go weeks and not have the psi change, then i may have to top up the psi every few days, then back to normal...so in conclusion :spudwhat: :spudwhat: FAKD IF I KNOW, but all my bikes have been like it....i wouldnt think having it on a stand would make any diff......

bugjuice
17th February 2005, 16:41
pressure shouldn't drop for weeks.. get the valve and rim checked. If you can get a huge volume of water (paddle pool, bath tub etc) and dunk the wheel in, see where the leak is.. I check mine every few weeks, and hardly ever needs topping up.. reminds me, I should check it actually..

カワサキキド
17th February 2005, 19:07
Sounds like you have got a microscopic hole, those little suckers are near impossiple to find in the trye bath but it's worth a try, get the vavle and steam replaced any way and the rebead the trye making sure the rim and bead are really clean. Occasionally you see porous rims but I don't think thats very likely.

dangerous
17th February 2005, 19:22
Is loosing 1psi over 8 hours acceptable?
Finally, there should be no adverse effects with keeping the back on the stand constantly when not in use?
Well...... I'd say yeah its ok to loose that kinda psi, put it this way the Guzzi would loose that dident mater if I changed the tyre or valve..... I think its something that happens to sport tyres.
I was of the belief that slicks loose pressure rather fast... duno why tho, the VTR drops in psi in 1-2 weeks all the time and its new.

Stony I keep the bikes on the paddock stand all the time wouldent be without it, cant harm anything and its a shit load safer should the kids next door sneak in and clime aboard.

marty
17th February 2005, 20:44
it's normal if you have a hole in the tyre.....but you shouldn't otherwise be losing that much.

StoneChucker
17th February 2005, 21:56
So I gotta go and PAY to have it checked, refitted, fixed, replaced, whatever! Man, I got so many farking bills at the moment! The rear tyre is looking a little chewed up, maybe just ride it out till I need a new one??? Infact, it looks pretty odd - could lots of wheeling (practice) do that?

dangerous
18th February 2005, 04:55
it's normal if you have a hole in the tyre.....but you shouldn't otherwise be losing that much.
even with brand new tyres....... like I mentioned

What?
18th February 2005, 05:29
Raising the tyre off the ground will decrease the rate of pressure loss, but not by a measurable amount.
Replace the valve core - it may well be the problem and will only cost you a few cents to find out. If it is not the core, it could be a puncture (tiny and hard to find), valve stem, tyre bead or porous rim.
The loss rate you mention is not good - not for your car either. Obviously you need to be checking your tyre pressures daily...
Personally, I'd live with it until the tyre is stuffed, then get the rim sealed while the tyre is off, as well as replacing the valve stem and core. This means you will never know what the fault was, but you won't be chasing it around, either.

Pwalo
18th February 2005, 07:03
Sorry mate, they're all correct. You've got a problem. Get it fixed before it hurts you.

What a pain in the arse, eh?

MSTRS
18th February 2005, 08:16
When you do sort it, you'll tell us what was wrong, won't you? Ta muckly

Oscar
18th February 2005, 08:33
Excuse me if these points are obvious, but:

1. When are you measuring PSI? Hot/Cold tyres and even ambient temp. will give you different readings.

2. Have you a valve cap on?

3. Are you using the same gauge? Those slidey pen gauge things are useless, as are most service station gauges.

vifferman
18th February 2005, 08:37
Nah, mate - you shouldn't be losing any air. Either the valve is leaking, or the tyre's got a small hole (check for nails or other objects in the tread) or the tyre bead isn't seated properly on the rim.
If the tyre looks "odd" or whatever the fark you said) then it's probly coz of the pressure being low when your riding - that'd chew the hell out of the tyre.

And Oscar - your talking shit mate, I've used those "pen type slidey gauge things" for years and a decent one is pretty accurate - better than some of the cheaper digital or dial ones that cost more. :shake: Just depends on the brand and how you look after it. And any gauge you use should be checked periodically against a known good one.