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34

As you mentioned, one of the primary differences between a Presta and Schrader valves are the diameters--with Schrader valves being slightly larger--and therefore the valve holes on bicycle rims are drilled to suit one size or another. Your foremost concern with using a Presta valve in a rim drilled for a Shrader valve shouldn't be 'movement' of the valve ...


30

The cap keeps dirt and rocks away from the valve, particularly the fragile release mechanism. It's not the end of the world if the caps are missing, but I suggest leaving them on. They don't take that long to remove and replace.


14

Nobody has noted this yet, so maybe I'm particularly clumsy. The caps prevent you from bending the somewhat delicate presta valve stem if, like me, you're fitting a fairly beefy lock between your spokes every day. I smacked mine pretty good after a groggy morning commute, and it bent the valve stem pretty severely. They're somewhat known for snapping off ...


14

smaller hole in the rim is good (presta +) schrader has piece that inserts into the valve (screws in) with a spring mechanism to seal it - these parts sometimes fail (schrader -) presta uses tire pressure to seal it (presta +) rocks can lodge in uncapped schrader and cause leaks (schrader -) presta does not need a valve cap to keep rocks out (presta +) ...


13

What I find helps, is: tap the valve post a bit to let out a small blast of air (after loosening the captive nut all the way, of course). That helps unstick things and lowers the pressure inside a bit to make it easier to start pumping air in. Just takes a quick tap. If you don't do that, you may need to pump slightly past the pressure of the tire to ...


12

Drilling out your rims will reduce the strength of the rim and increase the likelihood of cutting the valve stem on your tube. For a few dollars you can buy two of these: This adapter threads onto a Presta valve and effectively turns it into a Schrader valve. Presta valve tubes are the same price and are as widely available as Schrader valve tubes, so you ...


11

Presta's main benefit is more about how the valve functions, in regards to getting pumped up to higher pressures. Because the stem of the valve needs pressure in the pump head to get high enough before it pushes the valve stem in, and start flowing air into the tire, when you try to get to 120 to 160 lbs of pressure it works better than a Schrader valve ...


10

Those valve stems are too short for those deep deep rims you've got on there. You can tell just from the photos that the valve stem isn't sticking out far enough from the rim for the pump to fit all the way on it. Hence, it's not contacting the valve enough for you to inflate your tires.


9

A tube should not have excess length, and doubling on itself will cause the tire to feel uneven while riding, as well as increase the likelihood of flats. Assuming the tube is the correct size for the tire, as you said it was, there are 2 common causes for this problem. If you installed the tube without inflating it first, just a tiny amount, then it ...


9

In case you really want to drill, the only thing you need is a 10mm drill bit, and a sandpaper to give a smooth finish. It is true that the rim gets weaker, and very narrow rims should not be drilled, but I have performed this enlargement a couple of times and rode the wheels some honest hundreds of km in every kind of terrain, with no problem. I did this ...


9

The advantage is that it's quicker and easier to get the tube out and tyre off, and you never have to deal with jammed nuts. IME the nut will be wedged unbelievably tight the one time you get a puncture at an inconvenient moment, and you'll end up breaking the valve (if you have pliers) or not being able to get at the hole (if you don't). The problem there ...


8

Don't bother with an air compressor. Get a proper bike pump. They are cheaper, and will fill a tire to 60 psi with minimal effort. A good bike pump will also require less maintenance. Also it'll only take a couple pumps to top up your tires. Much less time than to drag out a big air compressor. Have you had problems with standard floor/track pumps? What ...


7

It is for adjusting the suspension on a medium to high-end mountain bike (fork), hence the lack of 'Presta' option. Since you will be returning it, to keep the shop happy and get what you really need, consider getting: A track pump with gauge and aluminium body. Look for one with a well engineered head that does Presta and Shrader valves. The easiest ones ...


7

Can I calculate (approximately) how much air pressure is lost by measuring the hose length and diameter? No, you cannot tell how much pressure is lost based on the size of the hose. This is not because there is not enough information to tell but because the hose is irrelevant. You seem to be under the impression that there is some total amount of ...


6

Yes you can. Many presta tubes come with a grommet to allow you to use presta valve tubes in a wheel drilled for schraeder valves.


6

On my MTB I leave them on to keep mud from crudding up the works. On road and commuter bikes they are useless and I toss them.


6

Because you only fill one tire at a time. The adapter screws off and can be used on either tire if needed. It can also be easily stored with your patch kit, so it doesn't need to be on the bike. I only keep one around in case I get stuck with only a schraeder pump at my disposal.


6

I used to skin my knuckles every time I took the chuck off the valve. Then I figured it out (pain is a learning curve accelerator). Position the wheel so the presta valve is closest to you and pointed away from you. Use your thumbs on either side of the wheel to push the chuck straight off (toward the hub of the wheel). This prevents the presta stem from ...


6

I have had such experiences even at much lower pressures, (I ride diverse disciplines of mountain bike, so I use my tires around 40 PSI, but still...). I have found three main causes for inflation difficulty: I will discard air leaks as this one is pretty obvoius. 1) Faulty valve: Some valves get somewow obstructed, and won't get air in as easily as it ...


6

I prefer having the nut, because it makes pumping much easier, especially road side with a frame pump. I put them on finger tight and then retighten after inflating, and I've never had one jam, or rattle.


5

They have one big benefit on road / commuting bikes - they stop the valve corroding and seizing due to the salt and crap they get exposed to. On a mountain bike, this isn't such a problem, as the salt gets washed off by puddles and mud (and you tend to wash your mountain bike more). That's been my experience in the muddy, wet UK, when the roads are salted ...


5

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 ...


5

The liters/minute capacity of a compressor says nothing about it's max pressure. Most compressors intended for air tool use are good to about 100psi, maybe 120, but you need to make sure before you spend your money -- the compressor needs to do maybe 30% higher pressure than your "target" pressure, or you'll be forever waiting for the tires to fill. But as ...


5

I think the valve should be as short as possible while still allowing comfortable inflation of the tire. On the other hand, a longer valve usually "won't hurt", specially if you have more than one bike or your group of fellows use to lend spare tubes to one another during rides (happens a lot to me, but in shcraeder-equiped mountainbikes). Hope this helps! ...


5

I swapped out both tubes on my mountain bike with Presta (less chance of crap getting in to the valve and it means I can carry the same CO2 inflator as I do on my road bike) and got the bushings - once they were in I've had zero issues with the valve stem. I'd definitely recommend putting one in since there's the chance that the valve stem could rub against ...


4

Yes, you can remove the adapter and put it on the rear tire. The reason for putting on an adapter is so that you can use air-compression equipment which is available at gas stations etc. You don't actually need it if you have a good pump at home which is two fit (presta and schrader).


4

Keep the cap on to protect the valve from accidental damage, dirt, salt and oxygen. There is a bit of rubber inside the Presta valve: Leave the valve cap off and oxygen in the air gets to the rubber causing it to perish. This problem will take time to develop, however it will do regardless of where you live, where you ride and how often you clean your ...


4

Make sure you unscrew the presta valve first. There is a small top piece that must be unscrewed before you place the pump onto the valve. If all is correct, you should be able to press onto the presta valve and air will be released. Once your presta valve is open, place the pump nozzle over the valve with the locking tab DOWN. Press firmly (you might ...


4

I've never had this problem. It would take considerable force to bend the stem. First be sure you have the nut on the Presta stem, and that it is screwed down firmly against the rim (though it shouldn't be wrenched tight). This will keep the stem from wobbling around in the rim hole, and makes the whole job easier. Then make sure that the wheel is ...



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