SuzukiSavage.com - Tubes and slow leaks

DavidOfMA

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Tubes and slow leaks
04/10/13 at 08:54:05

It's been such a long time since I had tubed tires that I can't recall if what I am experiencing is "normal."

When I got my bike, the original owner had recently replaced the rear tire. Pressure was good, but a week after I got it, I checked the pressure again and it was down about 12 pounds. However, after several refillings with air, the leak seemed to stop and the tire has retained pressure since.

Last week, I had the front tire and tube replaced. When I checked the pressure a few days later, it was about 13 pounds down. I refilled, and overnight it lost about three pounds. I refilled again, and now the overnight pressure loss is at most a pound. I had planned to take it to the dealer to have the tube replaced, but now I'm wondering if it's "normal" for tubes to lose pressure, and then after a while to stop losing it. I did tighten the valve core, but it didn't appear to be loose when I did.

Anyone else have this experience?

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- David

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28637 Tucson Az Gender:	Re: Tubes and slow leaks Reply #1 - 04/10/13 at 09:46:36 Should be about the same as tubeless.. Lose a few lbs over months... not days... Do you spit test the valve after filling?... Most of the time,.. it's the valve... Slow punctures are rare on street bikes...
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DavidOfMA

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Re: Tubes and slow leaks
Reply #2 - 04/10/13 at 09:59:29

I did spit test the valve, and it didn't bubble, though I tried to tighten it anyway. If the leak continues, I'll take it back to the shop. The strange thing is that the leak is slowing, which is what happened with the rear tire, too. You'd think it they pinched or punctured or nicked the tube when they installed it, the leak would be consistent.

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- David

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28884 L.A. California Gender:	Re: Tubes and slow leaks Reply #3 - 04/10/13 at 10:06:57 funny how it's repeated from tube to tube. maybe the rim and tire are nearly sealed and it takes awhile for all the tire to get out and the tube fully expand. I'd take the valve out and clean it off, sometimes the powder they use gets stuck in the valve.
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oldNslow

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Re: Tubes and slow leaks
Reply #4 - 04/10/13 at 10:11:14

Another possibility is that someone used Dyna Beads to balance the tires. The beads can actually get caught in the valve when you check the presure and not allow it to close completly, causing a slow leak. Happened to someone I know last summer. Not real likely but it does happen. I think I'd just replace the valve stems and see what happens.

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DavidOfMA

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Re: Tubes and slow leaks
Reply #5 - 04/10/13 at 10:26:14

I'll try cleaning the valve core. Since it's a tube, the valve is new, but that doesn't mean it's perfect. The expanding tube theory is interesting and makes sense, too. If the tube was scrunched and then expanded, it would be larger and the air pressure inside would drop. I'll also try overinflating it by a few pounds and riding around a while to make sure the tube is completely seated in the tire.

Thanks, as always, for your suggestions.

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- David

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Digger Serious Thumper 2005 No Login Offline Ya gotta be tough to ride singles! Posts: 1604 Colorado Springs, CO Gender:	Re: Tubes and slow leaks Reply #6 - 04/10/13 at 18:53:57 DavidOfMA wrote on 04/10/13 at 08:54:05: ...Anyone else have this experience? Offhand, I would not consider that to be normal......
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WD Serious Thumper 2005 No Login Offline Professional "scooter trash". Posts: 5207 Rosemark TN Gender:	Re: Tubes and slow leaks Reply #7 - 04/10/13 at 22:55:17 Cold night air will pull a cheap tire/tube down in a hurry.
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DavidOfMA Senior Member Offline Getting back in gear after a long time away Posts: 336 Beverly, MA Gender:	Re: Tubes and slow leaks Reply #8 - 04/11/13 at 05:30:09 WD wrote on 04/10/13 at 22:55:17: Cold night air will pull a cheap tire/tube down in a hurry. Yup, sure will. Not what's happening here.
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apache snow-FSO Serious Thumper Offline Posts: 509 Gender:	Re: Tubes and slow leaks Reply #9 - 04/11/13 at 05:59:22 The rule of thumb is for every 10° Fahrenheit change in air temperature, your tire's inflation pressure will change by about 1 psi (up with higher temperatures and down with lower).
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DavidOfMA Senior Member Offline Getting back in gear after a long time away Posts: 336 Beverly, MA Gender:	Re: Tubes and slow leaks Reply #10 - 04/11/13 at 06:15:35 Thanks. I hadn't been able to work that out empirically. Is that 10 degrees/1psi pretty much the same across tire sizes?
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Tubes and slow leaks Reply #11 - 04/11/13 at 06:18:54 Look up Boyles Law, PV=NRT, where pressure X volume = Moles X Gas Law Constant X Temperature. Its really a fun little equation. In college I could get so close to answering the gas law questions w/o a pencil it was downright funny,,watching the classmates get eaten up by it.
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bill67 Serious Thumper Offline old tired Posts: 8517 genoa city wisconsin Gender:	Re: Tubes and slow leaks Reply #12 - 04/11/13 at 06:29:51 justin_o_guy2 wrote on 04/11/13 at 06:18:54: Look up Boyles Law, PV=NRT, where pressure X volume = Moles X Gas Law Constant X Temperature. Its really a fun little equation. In college I could get so close to answering the gas law questions w/o a pencil it was downright funny,,watching the classmates get eaten up by it.
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apache snow-FSO

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Re: Tubes and slow leaks
Reply #13 - 04/11/13 at 06:30:19

I believe that has more to do with the relationship between pressure and volume.

Boyle–Mariotte law) states that the absolute pressure and volume of a given mass of confined gas are inversely proportional, if the temperature remains unchanged within a closed system.[1][2] Thus, it states that the product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662.[3]

There is really no reason to over complicate this..

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73

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justin_o_guy2

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Re: Tubes and slow leaks
Reply #14 - 04/11/13 at 06:55:57

Yup,, & knowing this I am Still amazed when I check pressure on a tire that Doesnt have a car or a backhoe sitting on it, then put the weight of the vehicle on it, check it again & cant even see it on the gauge.

& Theres ANOTHER Variable,, gauges,, Ive had as many as 4, some, the very cheapest available, a "Truckers Gauge", heavier, longer, to go to higher pressures, with the head that can go inside of a dually setup, IIRC, 8 or 9 bucks, And a dial/needle with a release valve. The blasted "normal" gauges w/ the stick that slides out will often disagree by several pounds, then dang if they wont suddenly agree. I even went so far as to lube the stick on the truckers gauge w/ graphite,, still doesnt agree with the dial gauges. I have 2 of them, one holds the reading, the other,, ehh,, no.,but, so far, I trust the needle/dial gauges a lot more. I threw 3 of the cheapo stick gauges away just last week,
Not only do they not agree with each other, sometimes they wont read the same if I take several readings, & yea, I know about getting them on square & not letting air bleed around them..

& Just What is WRONG with Overly Complicating things? YOu DO realize some of us Live just for that, right? Jeeze Louise! You tryin to take ALL the fun outta this stuff?

I LIke Complicated! Gimme complicated! Dont you dare take my complicated away..

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The people never give up their liberties but under some delusion.- Edmund Burke.

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