Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Tube leaks only when riding, stops at 17 psi

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Tube leaks only when riding, stops at 17 psi

Old 05-09-20, 03:32 PM
  #1  
Arthur Peabody
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 379
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Liked 21 Times in 15 Posts
Tube leaks only when riding, stops at 17 psi

Yesterday my front tube was at 17 psi after a few hours of riding. At home I took it off, couldn't find a leak, pumped it up. It was still 90 psi this morning, but after a couple of hours riding, it was 17 psi. I still can't find a leak - I looked harder this time. I couldn't find anything in the tire, not even with a ball of cotton. The liner and tube protector have nothing in them.

What kind of leak happens only when riding? Stops at 17 psi?

It's a cheap tube, CST, repaired once, last September.
Arthur Peabody is offline  
Old 05-09-20, 03:34 PM
  #2  
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Valley of the Sun.
Posts: 34,331

Bikes: everywhere

Mentioned: 56 Post(s)
Tagged: 1 Thread(s)
Quoted: 5353 Post(s)
Liked 1,052 Times in 565 Posts
Originally Posted by Arthur Peabody View Post
Yesterday my front tube was at 17 psi after a few hours of riding. At home I took it off, couldn't find a leak, pumped it up. It was still 90 psi this morning, but after a couple of hours riding, it was 17 psi. I still can't find a leak - I looked harder this time. I couldn't find anything in the tire, not even with a ball of cotton. The liner and tube protector have nothing in them.

What kind of leak happens only when riding? Stops at 17 psi?

It's a cheap tube, CST, repaired once, last September.
It's common for a tube to hold air at low pressure. It'll have a small hole that remains closed at low pressure, but opens up as tube is inflated.
LesterOfPuppets is offline  
Old 05-09-20, 03:39 PM
  #3  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,091

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1100 Post(s)
Liked 644 Times in 451 Posts
I had a tube like that and it had a tiny pin hole in it. It held pressure for awhile but eventually lost it until it reached a certain pressure. What was happening was that after losing a large amount of pressure the tiny hole was so small it was effectively sealed. I finally found that pinhole by taking the tube entirely out of the tire, pumping it up a LOT and then holding small sections of the tube under a large pan of water. I eventually spotted the very small bubbles escaping from the pinhole.

I carry a spare tube to change on the road and I also carry a small bottle of Stan's Tire Sealant to use if I get such a hole again and need that tube.

Cheers
Miele Man is offline  
Likes For Miele Man:
Old 05-09-20, 03:58 PM
  #4  
Crankycrank
Senior Member
 
Join Date: Jan 2009
Location: San Diego, CA
Posts: 1,676
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 275 Post(s)
Liked 82 Times in 66 Posts
Pull the tube out inflate and wiggle the stem around and check for tears at the base. I've seen many cracks and tears around the stem that will hold air until it gets ridden and moved around slightly. If you haven't already, submerge the inflated tube in a bucket of water which will release bubbles at the puncture.
Crankycrank is offline  
Old 05-09-20, 04:40 PM
  #5  
texbiker
Senior Member
 
texbiker's Avatar
 
Join Date: Jan 2012
Location: Kingwood, TX
Posts: 864

Bikes: Canyon Endurace CF SLX, Blue Norcorss AL, Lynskey R300

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Liked 20 Times in 20 Posts
When I can't find the leak I take the tube, air it up to 80 to 90 psi, and slide the tube through a tub of water slowly and watch for bubbles. This works all the time for me. Regarding the 17 psi, that may be close to the atmospheric pressure where you are and the pressure equalizes with the pressure.
texbiker is offline  
Old 05-10-20, 12:38 PM
  #6  
Arthur Peabody
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 379
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Liked 21 Times in 15 Posts
Originally Posted by Miele Man View Post
I finally found that pinhole by taking the tube entirely out of the tire, pumping it up a LOT and then holding small sections of the tube under a large pan of water. I eventually spotted the very small bubbles escaping from the pinhole.
I don't consider a tube inspected for leaks until I have removed it, pumped it up as much as a tube can take (about 2 pounds, according to FBinNY), and putting it in soapy water (soap enhances bubbles.) That I reported that I inspected the inside of the tire, the liner and protector, evidences that I removed the tube.

Originally Posted by Miele Man View Post
I carry a spare tube to change on the road and I also carry a small bottle of Stan's Tire Sealant to use if I get such a hole again and need that tube.
Sealants have never worked for me. I carry 2 spare tubes, haven't repaired a tube on the road in years.

Originally Posted by Crankycrank View Post
Pull the tube out inflate and wiggle the stem around and check for tears at the base. I've seen many cracks and tears around the stem that will hold air until it gets ridden and moved around slightly.
It looks okay. It's a new tube. Failures around the base of the stem have been obvious to me in the past.

Originally Posted by Crankycrank View Post
If you haven't already, submerge the inflated tube in a bucket of water which will release bubbles at the puncture.
I'm surprised anyone suggests this. It never occurred to me that someone would report a leaky tire before submerging it for a check.

Originally Posted by texbiker View Post
When I can't find the leak I take the tube, air it up to 80 to 90 psi
A tube explodes with only a few pounds of pressure. I've done it.

Originally Posted by texbiker View Post
slide the tube through a tub of water slowly and watch for bubbles. This works all the time for me.
Of course I tried this. I asked here because it didn't work for me this time.


Originally Posted by texbiker View Post
Regarding the 17 psi, that may be close to the atmospheric pressure where you are and the pressure equalizes with the pressure.
You use a gauge that measures absolute pressure? Does anyone else in the forum? I doubt it. Mine measures relative pressure, the pressure above atmospheric.
Arthur Peabody is offline  
Old 05-11-20, 01:29 AM
  #7  
tFUnK
Senior Member
 
Join Date: Jun 2002
Location: San Jose, CA
Posts: 2,691

Bikes: Too many bikes, too little time to ride

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 101 Post(s)
Liked 44 Times in 40 Posts
Was gonna say check the valve base but you mention it's a new tube.
Is this presta or Schrader? Either way, it could be the valve core. If it's removable presta core you can take it out and inspect/clean the rubber gasket part. It's been a while since I took out a Schrader core but try doing similar. It could just be not screwed in fully. If presta, make sure to close the valve nut tight after inflating.
tFUnK is offline  
Old 06-02-20, 02:53 PM
  #8  
Arthur Peabody
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 379
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Liked 21 Times in 15 Posts
I replaced the tube with a thorn-resistant (because thick) and, 3 weeks later, the same thing happened: it started leaking only when riding, stopped at 17 psi. I can't find anything wrong. I replaced the tire, though it still has a lot of tread.
Arthur Peabody is offline  
Old 06-02-20, 04:47 PM
  #9  
shelbyfv
Senior Member
 
shelbyfv's Avatar
 
Join Date: Jun 2007
Posts: 6,890
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1689 Post(s)
Liked 986 Times in 578 Posts
Originally Posted by Arthur Peabody View Post
I don't consider a tube inspected for leaks until I have removed it, pumped it up as much as a tube can take (about 2 pounds, according to FBinNY), and putting it in soapy water (soap enhances bubbles.) That I reported that I inspected the inside of the tire, the liner and protector, evidences that I removed the tube.


Sealants have never worked for me. I carry 2 spare tubes, haven't repaired a tube on the road in years.


It looks okay. It's a new tube. Failures around the base of the stem have been obvious to me in the past.


I'm surprised anyone suggests this. It never occurred to me that someone would report a leaky tire before submerging it for a check.


A tube explodes with only a few pounds of pressure. I've done it.


Of course I tried this. I asked here because it didn't work for me this time.



You use a gauge that measures absolute pressure? Does anyone else in the forum? I doubt it. Mine measures relative pressure, the pressure above atmospheric.
Kind of snippy replies to folks trying to help. I suggest if you are unable to find the leak, replace the tube. Too much drama for a tube.
shelbyfv is online now  
Likes For shelbyfv:
Old 06-02-20, 05:16 PM
  #10  
Juan el Boricua
Member
 
Join Date: Sep 2011
Location: San Juan, PR
Posts: 39

Bikes: 1980's Royce Union "fixer", 1995 Trek 370, 1985 Diamond Back MTN SS, 406 -wheeled " shopper/minivelo"for running errands, SS Raleigh M60

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked 3 Times in 3 Posts
Originally Posted by shelbyfv View Post
Kind of snippy replies to folks trying to help. I suggest if you are unable to find the leak, replace the tube. Too much drama for a tube.
This. If you come to a forum for the very first time to ask questions because you apparently needed help, people (without knowing your background or yourself) will answer from the very basic "common sense" type to an "almost a thesis dissertation" answer, to help a fellow member. If you wanted a specific answer, maybe ask for comments on your idea?; maybe be open minded; tolerant?
here goes my $0.02: buy a new tube or convert to tubeless and be done with it.
And why would you change a tire when it's the tube failing?

Last edited by Juan el Boricua; 06-02-20 at 05:20 PM.
Juan el Boricua is offline  
Old 06-03-20, 07:46 AM
  #11  
Arthur Peabody
Senior Member
Thread Starter
 
Join Date: Apr 2017
Posts: 379
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 124 Post(s)
Liked 21 Times in 15 Posts
Originally Posted by shelbyfv View Post
Kind of snippy replies to folks trying to help.
Originally Posted by Juan el Boricua View Post
If you come to a forum for the very first time to ask questions because you apparently needed help,
I didn't ask for help. I didn't understand why a tube would act this way. I asked in case someone had a sensible hypothesis.

Originally Posted by shelbyfv View Post
I suggest if you are unable to find the leak, replace the tube.
Originally Posted by Juan el Boricua View Post
why would you change a tire when it's the tube failing?
Because tubes kept failing, and in a way that I couldn't detect despite hundreds of tubes fixed over 50 years of riding.

Originally Posted by shelbyfv View Post
Too much drama for a tube.
You impute drama. I intended none.

Originally Posted by Juan el Boricua View Post
If you wanted a specific answer, maybe ask for comments on your idea?
I did.

Originally Posted by Juan el Boricua View Post
maybe be open minded; tolerant?
I am.

Originally Posted by Juan el Boricua View Post
buy a new tube
I already had, as someone who read my posts would have known.
Arthur Peabody is offline  
Old 06-03-20, 08:44 AM
  #12  
shelbyfv
Senior Member
 
shelbyfv's Avatar
 
Join Date: Jun 2007
Posts: 6,890
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1689 Post(s)
Liked 986 Times in 578 Posts
Happy you figured out a solution, with or w/o assistance....
shelbyfv is online now  
Old 06-03-20, 02:02 PM
  #13  
Litespud
Senior Member
 
Join Date: Oct 2017
Location: Chapel Hill NC
Posts: 826

Bikes: 2000 Litespeed Vortex Chorus 10, 1995 DeBernardi Cromor S/S, Nashbar 3sp commuter

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 318 Post(s)
Liked 243 Times in 144 Posts
Originally Posted by texbiker View Post
When I can't find the leak I take the tube, air it up to 80 to 90 psi, and slide the tube through a tub of water slowly and watch for bubbles. This works all the time for me. Regarding the 17 psi, that may be close to the atmospheric pressure where you are and the pressure equalizes with the pressure.
I donít think thereís anywhere on the planet where atmospheric pressure is 17 psi. All pressure gauges measure the pressure wrt ambient (atmospheric). So, a reading of 17 psi simply means that the tire pressure is 17 psi higher than ambient (~14.7 psi). The absolute pressure in the tube would be ~31.7 psi, but that numberís not relevant. Also, if you attempt to inflate a tube to 80-90psi, the pinhole will be the least of your problems
Litespud is offline  
Old 06-03-20, 02:47 PM
  #14  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 3,855

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1448 Post(s)
Liked 389 Times in 299 Posts
If I leak checked the tube in water and didn't find the leak, I'd put more air in it. If it still didn't show bubbles, I might put more air in it. If I repeat the process too much and the tube blows up. It's only four bucks.
Iride01 is offline  
Likes For Iride01:
Old 06-04-20, 08:20 AM
  #15  
pdlamb
Senior Member
 
Join Date: Dec 2010
Location: northern Deep South
Posts: 5,958

Bikes: Fuji Touring, Novara Randonee

Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 1213 Post(s)
Liked 294 Times in 207 Posts
Originally Posted by Iride01 View Post
If I leak checked the tube in water and didn't find the leak, I'd put more air in it. If it still didn't show bubbles, I might put more air in it. If I repeat the process too much and the tube blows up. It's only four bucks.
Only $4 for a tube? How long have you had that tube? How many patches does (did?) it have on it?
pdlamb is offline  
Old 06-04-20, 08:53 AM
  #16  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 3,855

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1448 Post(s)
Liked 389 Times in 299 Posts
Well tubes are pretty expendable to me since I do get them so cheap. So typically I don't patch them. I find old tube more useful to cut up into long strips and use them to hold furniture and stuff I build together as the glue dries. For many of those situations, more effective than clamps as odd angles can be handled easier. And many other uses too from simply tying bags shut to using the loop of an entire tube to wrap around something to hang on a hook on the garage wall. So often I'm short of old tubes when I need them since I really don't flat that often.

You can scold me for not using my LBS. But there are plenty of four dollar or less tubes still available online. I got mine from Walmart. Granted they aren't $4.00 anymore and maybe not the last time I bought them either, which was three years ago when I bought a half dozen or so.

https://www.walmart.com/ip/Bell-Stan...5-32c/34038251

https://www.bikeinn.com/bike/contine...mm/137172134/p

https://www.bikeinn.com/bike/bike-pa...1)+asc&start=0

https://www.jensonusa.com/Serfas-Road-Presta-Valve-Tube
Iride01 is offline  
Old 06-04-20, 12:00 PM
  #17  
robertorolfo
Senior Member
 
robertorolfo's Avatar
 
Join Date: Jul 2017
Location: Queens, NY for now...
Posts: 1,374

Bikes: 82 Lotus Unique, 86 Lotus Legend, 88 Basso Loto, 88 Basso PR, 89 Basso PR, 96 Bianchi CDI, 2013 Deda Aegis, 2019 Basso Diamante SV

Mentioned: 42 Post(s)
Tagged: 0 Thread(s)
Quoted: 844 Post(s)
Liked 90 Times in 65 Posts
Originally Posted by Arthur Peabody View Post
I didn't ask for help. I didn't understand why a tube would act this way. I asked in case someone had a sensible hypothesis.

I am.
Ah, so asking for hypothesis which could address an issue you are having isn't "asking for help." Got it.

For someone who becomes so irritated by the implication from others that you might lack some knowledge, you seem to have no qualms about doing the same exact thing to other people.
robertorolfo is offline  
Likes For robertorolfo:
Old 06-04-20, 03:02 PM
  #18  
Iride01
Senior Member
 
Iride01's Avatar
 
Join Date: Jul 2017
Location: Mississippi
Posts: 3,855

Bikes: '20 Tarmac Disc Comp '91 Schwinn Paramount '78 Raleigh Competition GS

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1448 Post(s)
Liked 389 Times in 299 Posts
I would think that explaining why a tube acts a certain way is help. Help in understanding. Whether the conversation directly contributed or caused you to have a Eureka moment, it still seems like help.
Iride01 is offline  
Likes For Iride01:
Old 06-04-20, 04:54 PM
  #19  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,091

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1100 Post(s)
Liked 644 Times in 451 Posts
Originally Posted by Iride01 View Post
If I leak checked the tube in water and didn't find the leak, I'd put more air in it. If it still didn't show bubbles, I might put more air in it. If I repeat the process too much and the tube blows up. It's only four bucks.
Not $4.00 a tube where I am. If you're getting tubes for $.00 each then you're very lucky.

I remember the situation I had that was like the O.P.'s. THe tire wiould very slowly lose air, I'd stop and pump it up again and it's very slowly lose air again. Unfortunately on that ridethere was no place where there was water to immerse the tube in to find that pin hole. I now carry two spare tubes and my patch kit. If I get stuck out in really crappy weather, I'll remove the valve core and put in some tire sealant. Those pin holes are precisely what tire sealant excels at filling.

Cheers
Miele Man is offline  
Old 06-04-20, 06:45 PM
  #20  
WGB
WGB
 
WGB's Avatar
 
Join Date: Jul 2017
Location: Niagara Region
Posts: 1,787

Bikes: League Fuji

Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 522 Post(s)
Liked 89 Times in 68 Posts
+1 for a tear at the Presta valve base. I have had at least 3 people ask for help with a flat this year who believed that little nut must be torqued down tight against the rim after inflating.
WGB is online now  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.