Jump to content

Why do some tubes leak slowly?

Recommended Posts

Back in the 80’s and 90’s when I had around 13 different bikes, on older tire technology and tubes, I never had a flat or had tubes lose air....ever. I know, I was lucky. Now that I’m a responsible adult who does all the servicings you’re supposed to do, I’ve had several flats. Usually within the first 15-30 minutes of a ride. When things are good, at best, my two bikes lose air slowly in all their tires between rides during the week just sitting. I use ultra heavy duty STI tunes. The valve stems aren’t losing air when I pour water over them. So what gives? Very frustrating.

Share this post


Link to post
Share on other sites

try a different tube? STI are uber cheap and thin, I use as a cheap tube to care on the trail. Likely even the UHD tubs are pretty thin.

  • Like 2

Share this post


Link to post
Share on other sites

I just binned Tubliss (separate story) and am now running UHD Bridgestone tubes. They come highly rated and so far they have been great. I used a lot of grease to install them. Inflated slightly, greased the buggers up and install was easy. 

Are you experiencing different temperatures, as in does it get cold at night? Could be why. 

Share this post


Link to post
Share on other sites

All tubes leak. Some leak more slowly than others. Don't use cheap tubes. Get fresh HD or UHDs from name brands.
I check my air pressure before every ride.


What pressure are you using? You might just be getting pinch flats.

  • Like 2

Share this post


Link to post
Share on other sites

I run 12 psi on my front. And 10-10.5 on my rear. I’ve had one pinch flat recently, one near the rim lock (maybe a bad install) two on the valve stem area (maybe I should loosen the valve stem nut and give some play?). I ride rocky terrain, but it’s the same riding area I rode 20 years ago when I never got flats. It’s just Wierd. I’ll try Bridgestone or Michelin’s next... or maybe just go tubliss. I don’t know. I’m just sick and tired of my riding days being ruined (and my buddies getting stuck with me) at the beginning of our rides.

Share this post


Link to post
Share on other sites
1 hour ago, MXR said:

I run 12 psi on my front. And 10-10.5 on my rear

I run 13 front and rear and only ride rocks (in Pennsylvania). I don't have flat issues, but I'm slow. My faster buddies do get pinch flats. You can always just try say 14 for a while.

  • Like 1

Share this post


Link to post
Share on other sites

What amazes me, is it's 2018, the tech breakthroughs we have are amazing, yet we're still riding around on air filled tires.

  • Like 2

Share this post


Link to post
Share on other sites
27 minutes ago, Fitz235 said:

What amazes me, is it's 2018, the tech breakthroughs we have are amazing, yet we're still riding around on air filled tires.

The telescopic fork is 100 yo technology yet nothing has been able to replace it so far.  

Because a tech is old doesn't mean it isn't the best solution.  Air filled tires are cheap, easy and effective.  They are also cheap n easy to fix.

  • Like 3

Share this post


Link to post
Share on other sites

Air the tires up to 15psi and I bet you won't have anywhere near the issues you are having now. 

The low air pressure trend magnifies the inadequacies of the design. Run bibs if you don't want flats. Or get really good at changing tubes on the trail if you want to run low pressure in the rocks.

  • Like 2

Share this post


Link to post
Share on other sites

They all leak a little. My current bike was bought new.  After 35 +- hours my front leaks twice as fast as my rear. 

 I used to ride much more than i do now. Id jump on and go with any free time i had.  With slime in the tubes my pressure didnt vary much and saved the 2 minutes to air up. Florida does have some cactus that would barely get through tires on occasion.

  • Like 1

Share this post


Link to post
Share on other sites

There are three basic technologies to provide air into a tire: tubes, the Tubliss (tm) system and mousse. Tubes work, are light, and easy to fix, but they all leak. HD tubes get fewer pinch flats but weigh more. UHD tubes get fewer pinch flats but weigh tons more. Weight in the wheel is bad in every way. Tubliss is two tubes at once, an inner tube at 100 PSI and the tire acting as a tube. Some folks love them. They leak down and you can get flats. All the extreme enduro pros use mousse. All of them have professional mechanics who change their tires and mousse every day.

  • Like 1

Share this post


Link to post
Share on other sites

Ya I've a STI HD tube once and ripped the valve out first ride and normally use IRC-IX Heavies but have a Bridgestone UHD rear as a back up that looks good. Run front 6 to 12 and rear 2 to 12 depending on tires and last flat I've had in 5 years was and actual piece of steel puncturing the tire/tube.

IMO if its a quality tube usually dirt in the valve from not using a valve cap or not making sure the valve is tight (I use spit) or you might have something stuck in the tire (like a thorn) or maybe a spoke.

The key when IDing a leak is making sure you know exactly how the tube was installed in the tire and how the tire/tube were mounted on the rim. Fill it up once removed and find out exactly where the hole is in relation to the tire/rim. Pinch flats or torn valves are obvious but if you find a leak in a weird place in the tube, it can help figure out what actually caused it IE finding something stuck in the tire that is just poking through into the tube and not obvious. You can use your fingers inside the tire but it might only poke out when the tire is compressed.

Slightly hard to explain and not sure if any of that made sense :)

I'm sure tubes at some point just lose air naturally but normally I check before every ride with a digital gauge and don't see any real air lose or maybe something like 0.5 psi over a few months.

 

Edited by filterx
  • Like 2

Share this post


Link to post
Share on other sites

Don’t tighten the nut on the valve stem.  Either remove it completely, or snug it up under the cap.  This will allow the stem to slip a bit and not tear it out.  Also allows you to see if the tire is slipping with a simple glance.

  • Like 2

Share this post


Link to post
Share on other sites
I just binned Tubliss (separate story) and am now running UHD Bridgestone tubes. They come highly rated and so far they have been great. I used a lot of grease to install them. Inflated slightly, greased the buggers up and install was easy. 
Are you experiencing different temperatures, as in does it get cold at night? Could be why. 

Not really. I’ve had slowly leaking tubes in my bikes all summer when the temperatures were consistent. I will have inconsistent temperatures now that fall/winter is coming and here.

Share this post


Link to post
Share on other sites
Ya I've a STI HD tube once and ripped the valve out first ride and normally use IRC-IX Heavies but have a Bridgestone UHD rear as a back up that looks good. Run front 6 to 12 and rear 2 to 12 depending on tires and last flat I've had in 5 years was and actual piece of steel puncturing the tire/tube.
IMO if its a quality tube usually dirt in the valve from not using a valve cap or not making sure the valve is tight (I use spit) or you might have something stuck in the tire (like a thorn) or maybe a spoke.
The key when IDing a leak is making sure you know exactly how the tube was installed in the tire and how the tire/tube were mounted on the rim. Fill it up once removed and find out exactly where the hole is in relation to the tire/rim. Pinch flats or torn valves are obvious but if you find a leak in a weird place in the tube, it can help figure out what actually caused it IE finding something stuck in the tire that is just poking through into the tube and not obvious. You can use your fingers inside the tire but it might only poke out when the tire is compressed.
Slightly hard to explain and not sure if any of that made sense
I'm sure tubes at some point just lose air naturally but normally I check before every ride with a digital gauge and don't see any real air lose or maybe something like 0.5 psi over a few months.
 

Thanks for the great advice. I understood what you said. Thanks for taking the time to explain.

Share this post


Link to post
Share on other sites
Don’t tighten the nut on the valve stem.  Either remove it completely, or snug it up under the cap.  This will allow the stem to slip a bit and not tear it out.  Also allows you to see if the tire is slipping with a simple glance.

My buddies and I have all had flats where the nut is tightened. I’m going to tell them what you said and hopefully that’s the issue or at least part of it.

Share this post


Link to post
Share on other sites

Tires cold in the morning are 2-3 psi lower than warm from riding or out in the sun.  Just saying maybe they didn't really leak that much ?    IRC HD tubes work for me, like the japanese synthetic rubber they use (vs real rubber that rots), don't like uhd or std,  thickness is consistant vs the china made tubes.  YMMV, mine did

  • Like 2

Share this post


Link to post
Share on other sites
2 hours ago, MXR said:

My buddies and I have all had flats where the nut is tightened. I’m going to tell them what you said and hopefully that’s the issue or at least part of it.

Never tighten the nut down onto the rim. If you do, and when the tire slips (and it will slip) it rips the valve stem out of the tube. Its bad, and it can't be fixed. If you don't just throw the nut away, tighten it back up against the valve cap so it can't get loose.

  • Like 1

Share this post


Link to post
Share on other sites
On 10/16/2018 at 7:37 AM, Gflo said:

Don’t tighten the nut on the valve stem.  Either remove it completely, or snug it up under the cap.  This will allow the stem to slip a bit and not tear it out.  Also allows you to see if the tire is slipping with a simple glance.

Ya I've read this but I use the top nuts on the valve stems snug tight and one Motion Pro rim lock front/back tightened correctly even with as low as 2 PSI on the rear, only ever had the STI rear tube valve rip but maybe I didn't have the rim lock tightened enough.

Rear and I mark the valve hole when changing tires, 2 nuts and use a valve removal tool with a rubber cap which is handy when changing tires :)

valve.jpg

Edited by filterx
  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×