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38

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, they’re wildly inaccurate even on cars. By the time they show red, you’re riding on your rims. Second, they’re cheaply made and a significant second point of ...


32

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 sealing effect.


19

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 with pressure too low. Burrs around valve hole. Knock down and replace with a neat bevel with swivel deburrer, tapered reamer, small round/needle/rifler file, ...


18

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, and the guts of it fell into your tube. This is what a removable valve core looks like: Your tube appears to be like the one on the right, with no removable ...


15

That's a very hard area to patch properly (if its even possible), and I'd recommend putting a new tube in instead of trying to patch it. . I'd also check that the rim tape on the rim is intact and in good condition, cause otherwise if its busted, you're going to get another cut. Also, as pointed out by ChrisH in the comments, rough edges on the rim hole ...


14

It should be straight out, perpendicular to the rim. Otherwise you risk damaging the tube. When the valve stem is at an angle the valve isn't free in the hole – it is trapped by the edges of the hole where they bind the stem. The edges of the hole may cut the stem which will be moving a little bit as the tire and tube flex over bumps and the like. There ...


14

It's a "dunlop" valve. Also called "woods". I used to see this years ago in BMX bikes. For best results we'd use to have a schrader adapter (google: dunlop to schrader adapter) so we could inflate with schrader pumps.


14

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're prone to forgetting this, what you need is a way to make the valve more obvious. I've had automatically illuminated valve caps before. That would do the ...


13

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 put the rubber and the red thing the other way around in. Such that the narrow pointy thing of the red part points outwards and the rubber has a wider opening to ...


13

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 core from a dead tube, break the plunger out of it to get more airflow, then temporarily install it in your tubeless valves and put your adapter on that. This is ...


13

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 tube. We have many questions and answers about using the valve here. You just unscrew the small safety bit on the pin, optionally screw on an adaptor and then you ...


12

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 of the rim and more to do with fitting the tire beads and valve into a narrow rim. If the rim is wide enough to accept a Schrader and mount the tire, its strong ...


11

My conclusion after many years of using not two, but three types of valves is that the best is the one that results most practical for you, acording to type of riding, type of pumping methods available and of course the type of bike/tire/rims you are using. Neither valve type is absolutely better than other, but one of them may result better for your ...


11

Yes. Slime makes some valve extenders for Schrader valves , and if you have a Presta valve you can use a Presta to Schrader valve adapter (and if you really want, you can attach a Schrader valve extender to that, since you can buy the Schrader valve extenders at Walmart or whatever) . Some companies (like Topeak) make Presta valve extenders as well: ...


10

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.


7

You could always buy some new tubes with the valve set at a 45 degree angle. Schwalbe sell them for £5/6 depending on the size you need. Easiest way I'd say and saves you faffing about drilling holes or screwing valve extenders on and off.


7

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're trying to inflate the tube and the stem doesn't move around when you're trying to pump the tire. Note that the tube can only go significantly into the rim ...


7

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. There are pumps that will inflate either, there are also pumps that only inflate one or the other. Many people use a pump with a built in gauge rather than ...


7

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/putting-tire-sealant-in-presta-valve-tubes/ If there is leaking, you could spray some soapy water around the valve to see where its leaking from. If its ...


7

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 immediately drops to zero (as these are all gauge pressures). Most of the hissing you hear is this air leaving the system When you reconnect the 0 psi in the hose ...


7

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'll probably show you if you ask.


6

For shorter stem presta valves in deep rims the trick to fill air is to first deflate the tyre about 50%, then push the pump head onto the stem with one hand while at the same time pushing the stem through the rim from the tyre side with your other hand. Then use the lever to get a good seal. When you pump it up, the increase in pressure in the head of the ...


6

You might want to remove your Schrader valve's stem (innards) with a stem removal tool and check the valve's rubber seat, located on the part that you remove. There may be debris lodged in the valve seat such as grit or sand or some dried slime that would cause it not to seat and seal properly. Also consider switching the valve stem core from another valve ...


6

Get a Dremel (rotary tool) with a cone shaped sander (e.g., the 3/8 in bit shown below). The sander will need to be wider than the diameter of a bicycle Schrader valve stem. You will use this to form a hole in an appropriately sized patch (i.e., a patch larger enough to have sufficient material on all sides of the hole). The hole needs to be the perfect ...


6

Answer: Yes you can. Woods/Dunlop valves have a nominal hole size of 8mm, identical to a Schrader/Auto valve. For completeness, a presta valve uses a 6mm hole. Reasons not to - authenticity of an antique bike, or maybe having to carry a second pump head/fitting if both tubes have different valves.


6

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. Unlike the valves on a car, the valves on bicycles are check valves that are held close by a higher pressure on the inside. When you pump, you will sense that ...


6

You're simply overtightening the valve caps. These caps do nothing to keep the air in the tube, so there's no need to do them up tightly at all. In fact most road cyclists just throw them away instead of using them.


6

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. There are adapters from Dunlop to Schrader, but the most common way to inflate these is a simple hand pump that has just a rubber gasket instead of chuck like ...


6

You have a Schrader valve. The pin on the valve core has been bent or the core is cross threaded in the stem - the picture is a little blurry. You can remove the core by unscrewing it from the stem. There is a special tool for that, sometimes skinny needle nose pliers can be used. Here are the options I can think of: If the pin is bent or the threads on the ...


5

Yes, the holes are different sizes. 6mm and 8mm, from memory. The hole size matters if you have skinny rims as 8mm out of a 20mm rim is a lot compared to 8mm out of a 40mm rim. But you already have valve holes. In theory putting a presta valve in a Schrader-size hole matters, in practice it doesn't. The base of the valve is where you'll see any effect from ...


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