|
SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Tubes and slow leaks /cgi-bin/YaBB.pl?num=1365609246 Message started by DavidOfMA on 04/10/13 at 08:54:05 |
|
Title: Tubes and slow leaks Post by DavidOfMA on 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? |
|
Title: Re: Tubes and slow leaks Post by Serowbot on 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... |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 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. |
|
Title: Re: Tubes and slow leaks Post by verslagen1 on 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. |
|
Title: Re: Tubes and slow leaks Post by oldNslow on 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. |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 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. |
|
Title: Re: Tubes and slow leaks Post by Digger on 04/10/13 at 18:53:57 393F3232363F343339382F5D0 wrote:
Offhand, I would not consider that to be normal...... |
|
Title: Re: Tubes and slow leaks Post by WD on 04/10/13 at 22:55:17 Cold night air will pull a cheap tire/tube down in a hurry. |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 04/11/13 at 05:30:09 091A5E0 wrote:
Yup, sure will. Not what's happening here. |
|
Title: Re: Tubes and slow leaks Post by apache snow on 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). |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 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? |
|
Title: Re: Tubes and slow leaks Post by justin_o_guy2 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. |
|
Title: Re: Tubes and slow leaks Post by bill67 on 04/11/13 at 06:29:51 3B242225383F0E3E0E36242863510 wrote:
::) |
|
Title: Re: Tubes and slow leaks Post by apache snow on 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 |
|
Title: Re: Tubes and slow leaks Post by justin_o_guy2 on 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.. |
|
Title: Re: Tubes and slow leaks Post by apache snow on 04/11/13 at 07:58:31 Sorry, the K.I.S.S. principle just makes life much easier. :) http://en.wikipedia.org/wiki/KISS_principle |
|
Title: Re: Tubes and slow leaks Post by Blinky-FSO on 04/11/13 at 08:22:32 5D4244435E5968586850424E05370 wrote:
JOG, My wife has her own gas law equation. It is BB+BR=NOC, where BB=Bean Burrito, BR=Beer, and NOC=Night on Couch. 8-) Good hunting |
|
Title: Re: Tubes and slow leaks Post by mnefred on 04/12/13 at 00:01:24 David, I had exactly the same thing happen a couple of weeks ago. Put on a new ME880 using the original tube. Lost about 5 lbs over night, but haven't lost any since. I like the 'wrinkled tube' theory. I've also noticed both tires lose a couple of pounds a week if sitting idle, but don't loose any if ridden every day. :-? Mark |
|
Title: Re: Tubes and slow leaks Post by Todd James on 04/12/13 at 07:58:11 I think Versy's analysis is correct (Reply #3). When you inflate a new tube there will be air trapped between the tube and the tire. That trapped air may escape in a number of places: 1) The hole in the rim for the tube's inflation stem; 2) Spoke holes in the rim; 3) The bead of the tire After the tube is initially inflated, it's air pressure will continue to drop until all of the trapped air escapes through these routes. That usually happens quickly (during installation and inflation) but could take some time and require several refills before all of the interstitial trapped air escapes. |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 04/12/13 at 08:43:47 The trapped air theory seems to be applying to my tire. Just checked it after letting it sit for two days. It's down one pound, but it's also about 10 degrees colder, so the apparent leak was actually not a leak, but either a scrunched tube or, more likely, air trapped between the tire and the tube that took a while to escape. Thanks for your help! Has anyone here had the rims converted so they will run without tubes? I noticed during my searches on Google on the subject of tubes that there is a company that modifies spoked wheels so that they will work without tubes. Seals all the leaks, installs a valve, for I think $60/wheel. |
|
Title: Re: Tubes and slow leaks Post by Dave on 04/12/13 at 08:43:52 2B000C0412350E0505610 wrote:
I haven't seen the use of the words "interstices" or "interstitial" since I had a "Mechanics of Materials" class.......33 years ago! |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 04/12/13 at 08:49:27 58636E7968647F79626A67780B0 wrote:
I haven't seen the use of the words "interstices" or "interstitial" since I had a "Mechanics of Materials" class.......33 years ago![/quote] I appreciate the use of that word, too, as a former PhD English major. Nicely put! |
|
Title: Re: Tubes and slow leaks Post by verslagen1 on 04/12/13 at 09:56:01 46404D4D49404B4C464750220 wrote:
I think one or 2 have done the DIY rim seal before and that was prior to that being available. I don't think anyone has specifically stated that they have had it done by that company though. Our rim is not very deep, so adding a seal and a protective layer will add to the difficulty in installing the tire. |
|
Title: Re: Tubes and slow leaks Post by DavidOfMA on 04/12/13 at 10:07:40 Thanks. I guess I'll stick to tubes. |
|
Title: Re: Tubes and slow leaks Post by WD on 04/12/13 at 17:46:04 Once you've converted for tubeless use, you can no longer adjust spoke tension. The gunk that is heat cured in a proper conversion gets into the spoke threads, the gap between rim and spoke nipple... Just something to ponder on. I finally gave up on one of the tubeless tires here. Can and a half of blow foam. Will be doing another cart tire and 16 mower tires the same way... One of my trucks still has tubed tires. The 1968/69 date coded tires will hold air for roughly 4 years without too many issues... The 2 year old tubeless gets topped off daily... :-? |
|
Title: Re: Tubes and slow leaks Post by Boofer on 04/12/13 at 22:47:19 While many people think the valve cap is just for looks, I can assure you it isn't. I use metal valve caps with a small o ring in them. It just may settle the slow leaks some experience. Schrader valves are not perfect, so a little extra protection doesn't hurt. :) |
|
Title: Re: Tubes and slow leaks Post by WD on 04/12/13 at 23:10:57 143939303324560 wrote:
Amen!!! And if your tube came with a chintzy plastic cap, throw it away and buy a four pack of good ones at Walmart. That way you have a couple spares for the inevitable "Where'd the cap go, it was right here" moment... |
|
SuzukiSavage.com » Powered by YaBB 2.2! YaBB © 2000-2007. All Rights Reserved. |