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41 votes
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Are there valve caps that show the tire pressure?

These types of valve cap gauges aren’t recommended - either for cars or bikes. They work by bypassing the schrader valve in the tire and using a cheap spring-based pressure gauge in the cap. First, ...
RoboKaren's user avatar
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32 votes
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How does a bicycle pump *head* work?

What you have is basically a cylinder of rubber. When you lift the lever, the cylinder is compressed on the circular faces. This results in the sides expansion, which will "hug" the valve giving the ...
L.Dutch's user avatar
  • 7,101
19 votes

Presta Valve Keeps Ripping From Tube

The usual causes for this: Presta valve in Schraeder hole without proper reinforcing grommet. Valve crooked, or being forced crooked at the expense of extra stress on the tube/valve joint by riding ...
Nathan Knutson's user avatar
18 votes
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Unable to pump air in my bicycle tube

I think its worse than that - your valve core is not there, but the thinner thread where you connect the airhose is there. That tells me the shaft of the valve core broke off, the acorn nut was lost, ...
Criggie's user avatar
  • 124k
14 votes

How can I avoid tearing the valve loose from an inner tube with a wheel lock?

A bike I sometimes borrow has one of these locks, and I can't say it's ever been a problem. You've given the answer in your question: Do not close the wheel lock between a spoke and the valve. If you'...
Chris H's user avatar
  • 58.3k
13 votes
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How does this hand pump work

From the disassembled photo, it looks like if you put the parts back together the pump will work for Dunlop valves and Presta/Sclaverand valves (roughly any narrow type valve). You should be able to ...
pseyfert's user avatar
  • 1,023
13 votes
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What air attachment screws onto a Presta valve with the core removed? High volume for seating bead?

Inflator heads with Presta fittings let you do this because they tend to (always?) seal down around the stem, not the core. I don't know any other way. I suppose you could also take a spare Presta ...
Nathan Knutson's user avatar
13 votes

Unable to pump air in my bicycle tube

You seem to be missing the valve core in your Presta valve. Perhaps you removed it? It is the most important part, it must remain in the valve. If you no longer have it, you need a new one or a new ...
Vladimir F Героям слава's user avatar
13 votes

Repeated punctures at the base of the valve stem

The rim hole in the second photo has a clear curve of silver metal. That looks like a sharp burr left over from the drilling process, and it will slowly erode its way into your tube. The solutions ...
Criggie's user avatar
  • 124k
12 votes

Presta or shrader valve for mtb?

The debate of Presta or Schrader is mostly religious and often based on poorly misunderstood facts or historical differences. Rim Width. In the 21st century, the problem is less about the strength ...
10 votes

Are presta valve cores universal?

I always save the core out of blown tubes and have never had them not compatible. At the bike store you just see one jar. Might someone come out with non-standard - it could happen.
paparazzo's user avatar
  • 15.7k
10 votes
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What is the typical structure and location of a check valve in a floor pump?

I managed to fix it! The only valve like thing I could find in the pump was a small bit of brass tubing, but it was hollow all the way through so figured there must a small ball that is displaced when ...
plodsmeade's user avatar
10 votes
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What are these female connectors called?

"THREAD-ON SCHRADER CHUCK" yields good search results
David D's user avatar
  • 21.1k
9 votes

"Soft" valve insert for easier pumping

With the car (Schrader) valve it also happens to me that I cannot start pumping. Usually when there is still some pressure in the tube. I am only creating a very high pressure region between the valve ...
Vladimir F Героям слава's user avatar
9 votes

Why is the retaining nut ("thumbscrew") against the wheel rim for inner tube Schrader valves no longer used?

Schwalbe tubes still have this feature. Schwalbe tubes are also high quality tubes with moderate weight, consistent construction (no lumpiness near the valve) and high latex content (helps rolling ...
BetterSense's user avatar
  • 3,366
8 votes

"Soft" valve insert for easier pumping

Cyclists today know the automotive style to which you refer as the Schrader valve. The valve with a rubber sleeve that you mention is called a Dunlop valve, also known as Woods. Within Dunlop valves ...
Nathan Knutson's user avatar
8 votes
Accepted

Considering modern bicycle trends (2021), why are presta valves still the dominant design?

I think you are correct; there is no technical advantage of Presta. But many things are not used for technical reasons but rather for momentum reasons. Personally I prefer schrader for all my bikes, ...
BetterSense's user avatar
  • 3,366
8 votes

Considering modern bicycle trends (2021), why are presta valves still the dominant design?

Presta (btw: we call it Sclaverand or simply road bike valve here in Austria) has one advantage: You can easily release air. There could also be some small weight savings and aerodynamic benefits. I ...
Michael's user avatar
  • 26.8k
8 votes
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repeated punctures at the valve stem

I would suspect you've got a Presta valve stem passing through a Schrader-sized hole in the rim. The Presta hole should be 6.5mm across, and the Schrader is 8.5mm That's not a lot of difference, but ...
Criggie's user avatar
  • 124k
8 votes
Accepted

How does a Presta valve core work?

Working from left to right of your first example: The black rubber gasket, when the brass nut is sufficiently tight, prevents air from passing through the core. The white rubber gasket, when the ...
Paul H's user avatar
  • 4,102
8 votes
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Repeated punctures at the base of the valve stem

It seems the tube has tried to move (probably dragged by tire while braking), and the valve was trying to prevent it from doing that. The result of that is shear stress not only on the part of the ...
Matija Nalis's user avatar
7 votes
Accepted

How tight should your stem valve nut be?

You don't need the nut, really (and its rather abnormal on Schrader valve tube) -- a lot of people just throw it away. The point of the nut is so that the tube's stem doesn't go into the rim when you'...
Batman's user avatar
  • 46.2k
7 votes
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Compatibility of pressure gauge with valve

There are Presta, and Schrader valves. There are also dunlop valves but they are far less common these days, especially in the US/UK. Schrader and Presta are two different diameters and valve types. ...
Nate W's user avatar
  • 9,232
7 votes
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Fixing the valves on tubeless tires broke, what are my options?

As long as the wrench flats on the valve core are still accessible, you should be able to replace just the valve core: from https://bicycles.stackexchange.com/a/36955/30982 http://k0lee.com/2009/10/...
Paul's user avatar
  • 1,981
7 votes

Is there a pump / Schrader valve adapter that prevent leakage during disconnection?

Much of the drop you see will be due to the reconnection, not the disconnection. When you disconnect the pump you have 120psi in the tyre and the hose, gauge and a little bit of pump. This ...
Chris H's user avatar
  • 58.3k
7 votes
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What is this valve and how do I fill it?

This is a Dunlop valve, also known as Woods. These valves always let air in but not out. The nut holds the valve in place, and you are supposed to unscrew it only if you want to deflate the tube. ...
ojs's user avatar
  • 22k
7 votes

broken presta valve confusion

The valve is broken. You need a new inner tube. A new tube will cost $5 to $10, and most bike shops will charge $5 or so to change it for you. It's something you need to be able to do anyway. They'...
Mike Smith's user avatar
7 votes

Repeated punctures at the base of the valve stem

I've had rim that caused punctures like that quite regularly. Covering the sharp edges of the valve hole with tape helped to some degree. Making them less sharp with a file or sandpaper might help as ...
Vladimir F Героям слава's user avatar
7 votes

When I press down on my presta valve cap when it is open why is no air coming out

Did you unthread the small acorn nut at the top of the presta valve? It should turn about 4 turns and once loose, you can press the top down and air should come out. If you don't open this nut, air ...
Criggie's user avatar
  • 124k
6 votes
Accepted

Open up blocked Dunlop valves

There are two types of Dunlop (or English) valves. I shall come back to these below. All valves have commonalities. First of all, one has to overcome the pressure in the tire before air flows into it....
gschenk's user avatar
  • 9,650

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