Pretty frustrated! I've just been through 3 tubes with presta valves and it looks like I've torn the valves out of the tube while removing the pump. This is very unusual for me, but I occasionally have isolated instances of this happening. I never screw the nut down to the rim on the valve, so that's not causing the problem. I've tried holding the nut to negate the pull when the pump hose is removed, but that doesn't seem to have worked. The only other thing that I can think of is that the pump hose attachment rubber on the valve may be too tight. This is a new pump that I can't recall having used before. I'm off to get more tubes to test this theory. Can anyone offer any other suggestions on what may be a problem with my technique?

On another tube related matter, while riding back from Adelaide a couple of years ago, I got a number of irreparable punctures around Junee. There is no bike shop there, but there is a horse place and I was able to get a few new tubes from them. They sell them for use on trotting rigs and the people who had the business were really good to deal with. They have proven to be the most robust tubes that I've had. 

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I'm a fan of the Lezyne pumps with the flexible hose so that it doesn't damage the valve/tube connection as much as a fixed pump head, since the removal process is to screw the hose off.

 

*However sometimes the removable core from my presta valves comes off, you would have thought someone would fix the design flaw on this. in the meantime , that's another use for loctite.

I use a track pump with a flexible hose, and carry and adapter for use with servo air lines.

Today not a great tyre day on M2: tradie screw in through centre of tyre and out through the wall. Tube too torn to patch, rim damaged, structure of the outer ruined as well. Walk and train home sarvo.

Thanks Peter. I've used this style of pump for many years without any problems. They've been particularly good while touring. I'll try out the rubber seal pressure when I get the new tubes and put it all together again.

Yes pumps with the flexible tube are the go for not putting shear forces on the valve/tube junction, i ripped a lot of valve stems before I got such pumps. I have got lazy(ier) last year and also carry a very small CO2 adapter and cartridge or two and this has worked perfectly (as a magic talisman) as I have not had a flat since I stated to carry it. In fact looks like I have not had a flat in 5,000kms (including 1200 with the Conti GP4000 S II)

The tyres on the Vivente have the larger tube hole so I use Schrader (auto) tubes and these are (IMHO) much tougher all round both in the junction and the valve itself and saves valuable seconds in not having to undo / redo the presta valve nut thingy, which often gets bent for me and has caused the valve to unscrew from the core as I unscrew the pump tube attachment, very annoying !!!, much swearing 

I'm with Peter and Lezyne (with the pressure gauge) and Bill with schrader. Back in the 70's when I opened a bike shop in Newtown the local boys called these "car" valves and a nice variation was "petrol" valves. Those were the days.

I bought this cheapy version with the pressure gauge for touring. Seems OK so far.

Where I've witnessed broken stems during pumping on presta valves there were too factors;

1. the stems are brass

2. the pumping was done with excessive sidewise force

I am likewise a fan of a screw on Lezyne pump and have both a track pump and a hand pump with flexible hose.  

I never use the nut (or the cap) on a tube.  Not really sure what the point of either those things is.  But it does add to the total time required to repair a flat if you use them.  

Could the problem be a bad batch of tubes?  I once had a few that all split on the seams after just a few rides.  No other explanation for what was going wrong.  

It can be impossible to get a push-on pump head onto a valve without the nut in some rim/valve combos if the air is low enough, without the nut.

The cap is there to keep the pump/valve interface clean and avoid small foreign objects being stuck to it and subsequently jamming the valve (or some other valve with the same pump later).

If I get a flat, I check the tire carefully, so its usually a 5 minute job to check it before putting a new tube in it (so a few seconds to screw off/on nut+cap isn't going to hurt), and if I can't find an obvious reason for the failure then I'd keep the tube and do another check when I get home (if it hasn't failed again).

One of the more unusual fails I've had is glass that worked its way from somewhere, somehow, to be wedged partly under my rim tape.  The first tube looked like it had split, so I didn't check the rim.  Not a huge believer in batch issues with tubes even if they are pretty cheap.

It appears that I may have been right in assuming that the tensioning screw for the rubber seal in the head of the pump hose was too tight. I backed the screw off a turn or 2 and had no problems getting it on or off the presta valve, as well as locking it when needed. It had originally compressed the rubber too much and made the grip on the valve too tight, so that when I tried to remove the pump hose the valve wanted to come with it. A useful lesson!

Not really an answer to your problem but I've always used schrader valves on my bikes. You can pump up at a petrol station if you are careful. Which I think could be useful if you break or lose your pump when touring.

Years ago when touring with the family on our tandems, I had an adaptor for the presta valves that would sort of turn it into a schrader valve and enable them to be pumped up at a servo pump. I think that I only used it once or twice, and I don't know where it now is or whether they are still available.

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