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Old 09-03-11, 02:49 PM   #1
vol
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Is the tube near the valve subject to damage by frequent pumping?

On most floor pumps, there is a lever at the head of the pump that you lift up to lock it on the valve (for some pumps, it's the opposite: you lift it before putting it on the valve, then press down to lock). This process more or less bends or "abuses" the part of the tube at the valve area, especially if when the lever is not very easy to be put in the locking position. It seems frequent manipulations like this will subject the valve area to damage, causing leaking tube?

(One reason I'm concerned about this is that I'm undecided whether to pump the tires whenever it's not hard full of air, even if still plenty of air.)
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Old 09-03-11, 02:53 PM   #2
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I always grab the ring on my presta valve before I pull off the pump head.
If its a schrader, I hold on to whatever bit of stem that is exposed.
I never had a problem. I suggest to pump up the tire if it's low,
otherwise you might get a pinch flat.
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Old 09-03-11, 03:12 PM   #3
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I also grab the ring around the Presta stem when removing the valve. I learned this trick the hard way on July 4, when I hurriedly pulled the pump valve off of the stem and heard the hissing sound as the tire deflated through a hole in the rubber at the stem. Since I have started holding the stem still by holding the ring, I have yet to encounter the problem again.

I tend to pump my tires every couple of days. Even if they feel nice and firm, I want to make sure they have sufficient pressure to prevent pinch flats.
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Old 09-03-11, 03:40 PM   #4
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Road bikes need their tires pumped up before each ride.
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Old 09-03-11, 03:50 PM   #5
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Yes and No.

The valve itself is unaffected by pumping, and until a few years ago neither was the tube. That's because the valves had fairly large metal base flanges which kept them from pulling through or wiggling in the rim. Over the years this base flange was eliminated and replaced by a molded rubber cone which glues the valve to the tube. Unfortunately to save dough, many makers have shortened the metal portion of the valve so it ends about 1/8" short of the tube. That means that the high stress zone where the valve passes through the rim is all rubber and it's no longer rare for valves to be broken off when hand pumping, or pulled out when the pump is disconnected.

Double wall rims give a bit of extra support, so breakage is less likely, but some extra care is still called for.

I ride tubulars (which still have base-flanged valves) on my road bike and remove the Silca hand pump by giving it a hard punch with the side of my fist to knock it off the valve. I made the mistake of doing that on my 26" PV commuter only have the valve come off with the pump.

I now shop tubes very carefully checking the base of the valve juncture with the tube.
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Old 09-03-11, 07:02 PM   #6
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Yes and No.

The valve itself is unaffected by pumping, and until a few years ago neither was the tube. That's because the valves had fairly large metal base flanges which kept them from pulling through or wiggling in the rim. Over the years this base flange was eliminated and replaced by a molded rubber cone which glues the valve to the tube. Unfortunately to save dough, many makers have shortened the metal portion of the valve so it ends about 1/8" short of the tube. That means that the high stress zone where the valve passes through the rim is all rubber and it's no longer rare for valves to be broken off when hand pumping, or pulled out when the pump is disconnected.
.
Welcome to a world going cheap. This way they can charge you $7 to $10 for a tube and not worry about another tube purchase happening every 7 to 10 years, now it can happen every 1 to 3 years if your lucky.

But there is a savior...besides Jesus; there are a couple of good semi mini pumps on the market that now come with a hose. Using a hose, like a home pump, puts far less stress on the pump then a pump that attaches directly to the stem. The best pump for the money is the Topeak Road Morph (a G after Morph means it has a built in gauge). The Topeak has a fold out L handle and a fold out foot peg, this pump will pump to higher pressures and do it easier then any other pump on the market. But it's external hose makes the pump look kind of ugly and it weighs a lot, but the heft of the pump does mean it's built sturdy and should hold up a long time. The other con is is that it doesn't come with a water cage mount to mount the pump off to the side of the cage...weird, but you can buy one from Topeak for $7. The price of this pump is around $25 on sale.

The other good mini is the Lezyne Road Drive, this pump is a very nice looking pump, the geniuses over at Lezyne hid the hose inside the pump for a much nicer looking pump and it weighs about 100 grams less then the Topeak. Con is the pump doesn't get to as high of pressures like the Topeak and it takes more effort to get to it's max of 110...not the claimed 160 from the manufacture, and this effort is high due mostly because there's no fold out handle and no fold out foot peg to assist with the pumping. The other con is the darn thing cost $45 to $47 and it doesn't include a gauge, but you can buy a optional gauge hose for $22, get both and your almost at $70 vs $32 for the Topeak if you get the cage mount.

And just in case your wondering, no mini pump on the market will reach the manufactures claimed psi rating! Most in fact will be lucky to get to 100 and that will be with over 500 strokes and a hard effort for the last 10 psi.

So eliminate some of the problems of the inferior built stems and get a bike pump with a hose.
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Old 09-03-11, 08:16 PM   #7
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Thanks for the comments. Looks like I do have to be very careful when inserting and removing the pump.
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Old 09-03-11, 08:22 PM   #8
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Thanks for the comments. Looks like I do have to be very careful when inserting and removing the pump.
You can also help yourself by developing a grip for the head end of the pump such that you brace your hand using your thumb against the rim. That way the pump and valve will be kept steady with respect to the wheel. I also suggest not bracing the bike or wheel against a wall, but pulling it off a bit so the wheel can move with the pumping motion.
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Old 09-03-11, 08:56 PM   #9
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Thanks for the tips. I'm glad I have asked this question before too late. Since I'm riding only a hybrid, I'll just pump it when it needs it. Some day I may get a Topeak Road Morph suggested here.
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Old 09-03-11, 09:17 PM   #10
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Thanks for the tips. I'm glad I have asked this question before too late. Since I'm riding only a hybrid, I'll just pump it when it needs it. Some day I may get a Topeak Road Morph suggested here.
You're approaching this somewhat backward. Rather than worrying about the tube, practice pumping until you're comfortable knowing you can pump it reliably without breaking the valve. It isn't repeated wiggling, it's more a matter of one time excessive force.

Twice so far this season, I've stopped to help cyclists stranded because they broke the valve pumping the spare after a flat. If you can't pump a repaired tire without braking the valve, the pump, tire levers and spare tube are totally useless and you might as well leave them home.
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Old 09-03-11, 10:11 PM   #11
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Thanks for the comments. Looks like I do have to be very careful when inserting and removing the pump.
I have been putting the valve nut on the inside of the tire for years. I don't have the problem. Just be sure that the tube is not under the bead at that point.
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Old 09-03-11, 10:12 PM   #12
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Road bikes need their tires pumped up before each ride.
I ride with 28's on the road and 32's on the tourer and they don't require daily airings.
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Old 09-03-11, 10:25 PM   #13
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I have been putting the valve nut on the inside of the tire for years. I don't have the problem. Just be sure that the tube is not under the bead at that point.
that assumes the valve is threaded down to the bottom, something that is very rare with SV tubes these days Pv tubes still seem to be threaded all the way, but most of those I've seen lately end about 1/8" short of the base. Putting the nut inside on these could cause the tube to tear at the valve as it tries to fill the gap caused by a valve held too far off the base of the rim.
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