Mountain Bike Reviews Forum banner
1 - 20 of 43 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter · #1 ·
Hi, Does anyone know of inner tube Shrader valve cores that do not leak air? Seems most cores leak air to a small degree, as I have to pump my tires every ride. Just wondering if there are cores on the market that are best at holding the air. Thanks!
 

·
Registered
Joined
·
1,617 Posts
What makes you think your cores leak? Did you bubble test them?

Whatever cores I have in tubed and tubeless setups only need new air every few weeks, no special valve needed. And rubber isn't 100% airtight either.
 

·
Registered
Joined
·
30 Posts
Discussion Starter · #3 ·
Well, I can't say a 100% that it's the cores. I can only tell by the pressure loss overnight and after rides. It seems the mostly likely culprit considering I can't find leaks on the tube itself. (Using the bubble test). I've tried tightening the cores by screwing them in as best they'll go.
 

·
EAT MORE GRIME
(ノಠ益ಠ)ノ彡┻━┻
Joined
·
7,876 Posts
wipe some spit on the valve, watch it

does it bubble or not ?
 

·
Registered
Joined
·
1,097 Posts
MTB tires and tubes are microscopically porous and will leak air when sitting around for a period of time. There's no special coating inside(like car tires) that minimize or prevent air loss.

Until bike tire manufacturers decide to put a coating inside the tires to prevent or minimize air loss, you'll just have to check your pressures regularly.
 

·
Registered
Joined
·
17,549 Posts
It seems the mostly likely culprit considering I can't find leaks on the tube itself. (Using the bubble test).
The bubble test should reveal leaks at the valve core too. Try overinflating the tube until it's 2 or 3 times it's normal diameter before immersing it in water to reveal small leaks.

Also tubes are permeable so they all leak to some degree, especially in high pressure tires
 

·
Registered
Joined
·
6,094 Posts
I have a bunch I can sell you. Although they look like regular valve cores, they are different and will hold air better. Will sell you 1 for $10 and 3 for $25.

I also have a special pump that will fill your tires with 78.09% nitrogen. $125+ shipping.
 

·
Registered
Joined
·
12,905 Posts
Remove your cores and make sure there's no dirt on the seals. Beyond that, no valve core, presta or shrader, is going to seal significantly better than another.

A tube should hold about the same pressure for days or weeks, depending on the outside temperature. If your tubes are leaking more than that, there's probably a hole somewhere. You can also squirt a little sealant like Orange Seal or Stan's in the tube to seal up small holes.
 

·
Registered
Joined
·
2,634 Posts
Well, I can't say a 100% that it's the cores. I can only tell by the pressure loss overnight and after rides. It seems the mostly likely culprit considering I can't find leaks on the tube itself. (Using the bubble test). I've tried tightening the cores by screwing them in as best they'll go.
Why are you screwing in the valve core on a Shrader valve?
 

·
Registered
Joined
·
9,754 Posts
My road tubes leak 2-4 psi/day. That's high pressure compared mtb tires so are gonna lose pressure faster. I don't remember how fast my tube mtb tires would leak down, but my tubeless tires leak down at least a couple psi/day. I always air up my tires before a day's riding, mtb or road, even if it's only been one day.

It's not the valves. Air diffuses through the rubber. CO2 diffuses more quickly than air.
 

·
Self Appointed Judge&Jury
Joined
·
45,098 Posts
This thread has win throughout. Like a fine wine it should only get better with time.
 

·
Registered
Joined
·
2,634 Posts
Why are you screwing in the valve core on a Shrader valve?
To tighten them?
gonna guess it's because they are screw threaded and screw in and out ?
haha good one!

To be clear, I meant to ask why OP is actually having to mess with the core.
I suppose OP is doing that because "its leaking" and therefore probably needs tightened.

I don't remember (personally) having to remove/install a Shrader valve core on a tubed tire.
 

·
Registered
Joined
·
17,549 Posts
haha good one!

To be clear, I meant to ask why OP is actually having to mess with the core.
I suppose OP is doing that because "its leaking" and therefore probably needs tightened.

I don't remember (personally) having to remove/install a Shrader valve core on a tubed tire.
They can leak, especially if there's sealant in the tube. Long ago I worked at a shop where the owner had us remove, oil, and reinstall the valve cores on every tube we installed.
 
1 - 20 of 43 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top