Ailing Floor Pump

[americancyclo]

I have the same pump going on about 7 years, but have not experienced any issues as of yet. Can you borrow another gauge to judge the pressure against? Were the blown tubes on the same rim?

[mstone]

I’d first suspect a pinched tube, to be honest. It’s possible to blow a properly mounted tube & tire off the rim, but you should notice that you’re pushing a lot harder to get the pressure up that high. (The manufacturers leave a pretty big safety margin, so this is not going to happen at only a few pounds over.)

[americancyclo]

Pinched tube or maybe something sharp in the tire or a burr in the rim

[Emm]

@SilverSpring 87940 wrote:

I’ve got a Topeak Joe Blow which has been a great floor pump for the past five years or so. Tonight, I followed the gauge reading as I was replacing a tube and managed to blow out two (2! More than 1! Arghh!) tubes. I didn’t think I was overinflating them, and the tire felt right, but I got one telltale bang and one insidious hiss. Assuming it wasn’t just tube problems, and assuming it was a gauge error, is there a fix for this?

The same thing happened to me on Friday, except only to one tube. The inside seam of the tube blew out after I installed it–a good inch was torn. I installed my only other spare tube, and was ridiculously careful about not snagging it on the rim during installation, or pinching it (not easy, as I have fingernails and cats that like to help fix bikes). Luckily, this did the trick (note: I also checked the rim AGAIN during this process, and it was fine). When I went to get more spare tubes, the hudson trail staff member agreed with the other posters here and said a pinched tube, or it could have been just a bad tube with a weak seam. He didn’t think over-inflation–It would have required WAY more pressure to burst the tube than I was likely to have done. Just be verryyy sloowww and veryyy carefull when you install the next tube and see if it helps.

To check your pump, you can buy a spare pump, and see how the gauge compares to yours, or borrow a friend’s pump. If it’s the same reading, just return the new pump. If it is the gauge, then you have a new pump so problem solved I checked my pressure using my mini-pump which also has a gauge since I also thought that was the issue. Since it came out the same as my floor pump, I figured I was just pinching the tube or something similar.

[SilverSpring]

Americancyclo,

That’s a good idea about borrowing a gauge…lemme poke around.

Mstone,

It could be pinched, although I’m much better at putting replacement tubes in than I was a few years back, when such an endeavor would’ve left me weeping.

Back to Americancyclo,

What would a burr look like? Something on the rim where the metal was etched or sticking out?

And Emm,

I had to carefully remove our cat from inside the tube (I’ve no idea how she got there, but don’t tell my Bride). I was certainly more ginger (ha, cat pun!) putting the third tube on and the slow pumping may have served me well…no more problems today. Hey, by any chance are you a PMF?

All,

Thanks much for the thoughts…good stuff to absorb.

[americancyclo]

@SilverSpring 88048 wrote:

Americancyclo,

What would a burr look like? Something on the rim where the metal was etched or sticking out?

yes, sometimes the inner part of the rim can get damaged after hitting a pothole, or there might be a small sharp edge near one of the spoke holes that was covered by rim tape that has become exposed. these can sometimes poke tiny holes in tubes, but can easily be found by running your finger around the inner edges of the rim and checking the rim tape. if found, they can be filed down pretty easily.

[Dickie]

@americancyclo 87952 wrote:

Pinched tube or maybe something sharp in the tire or a burr in the rim

@mstone 87947 wrote:

I’d first suspect a pinched tube, to be honest. It’s possible to blow a properly mounted tube & tire off the rim, but you should notice that you’re pushing a lot harder to get the pressure up that high. (The manufacturers leave a pretty big safety margin, so this is not going to happen at only a few pounds over.)

These! I can’t imagine a gauge error causing the problem you are describing. You would probably feel far too much pressure/resistance on the pump and stop before blowing the tube if the gauge calibration was off. I would continue searching for issues with the tire/rim/tape/spokes/installation.. etc.

[Emm]

@SilverSpring 88048 wrote:

And Emm,

I had to carefully remove our cat from inside the tube (I’ve no idea how she got there, but don’t tell my Bride). I was certainly more ginger (ha, cat pun!) putting the third tube on and the slow pumping may have served me well…no more problems today. Hey, by any chance are you a PMF?

Not a PMF. I magically got hired right out of grad school a few years ago through the normal hiring process (aka USAJOBS). The HHS office that hired me said it was the ONLY 9-13 job opening that year that wasn’t blocked, so of course they hired like 10 people off of it . If you need PMF friends though, about everyone else I know is a PMF, and I’m also very familiar with the program.

[SilverSpring]

Americancyclo and Dickie,

Got it, I’ll be attentive to the rim. I used to get a lot more flats and then I replaced my previously trusty Velox rim tape with some kinda plastic rim strip and that has been a charm against pokey spokes. I hadn’t thought to do a look armed with a file, though.

Emm,

Pretty cool that USAJobs worked. I don’t hear enough of those kinds of stories.

[Author]

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