Topeak Pocket Rocket

[pwa]

I'm sure I have a couple of Pocket Rockets on a shelf in the garage but their only use is when somebody asks me if they can borrow a pump. They are hard work and getting a 700x25 up to 90psi is something for only the strongest and most determined, if indeed it is possible at all.

Topeak do some good pumps, and they do some mediocre ones. The Pocket Rocket is one of the latter.

[skyhawk]

The point of the post is ?

[RickH]

I bought an even smaller Topeak pump - Micro Rocket ALT - back in 2008 & have found it works well enough (both with the 25mm tyres at around 95psi that I had then & latterly 40mm at 40psi) on the one day a year (2 if its a bad year) that I need a pump out on the road.

I noted after a rear flat on Clare's tandem in early 2018 (our only one in 2 1/2 years) that it took about 10 minutes to sort using a frame fit pump inflating a 32mm tyre to around 80psi.

Comparing that to a regular riding-to-catch-a-train run - the one time I had a rear flat, some time before the tandem incident, that also added about 10 minutes to my typical journey time using the micro rocket on 40mm tyres to get to around 40psi, despite its mere 20 cm³ stroke volume. (Both were wheel off, remove one tyre bead, tube out, check tyre, fresh tube in, refit tyre bead, reinflate tyre/tube, refit wheel.) I don't know which scenario involved pushing more air in - 1.5 or so times the tyre volume at around half the pressure with the bigger tyres.

[AndyK]

You just need to tighten them when you fit a new tube, either with a special tool, pliers or you may find the jaws on your chain tool fit. Alternative, buy tubes where the core doesn't unscrew.

Hmm. This does feel a bit like "it's not the pump that's wrong, it's ALL these damn innertubes that are wrong!" A much easier solution if you haven't already spent the money is "buy a different pump in the first place".

But if the cores in the tubes aren't fully tightened then you are going to be needing to pump the tyres more often because they are seeping a little air out of the valve.

And they will do that whatever type of pump you use.

Oddly enough this is not a problem that I have ever had.

[PH]

Hmm. This does feel a bit like "it's not the pump that's wrong, it's ALL these damn innertubes that are wrong!" A much easier solution if you haven't already spent the money is "buy a different pump in the first place".

But if the cores in the tubes aren't fully tightened then you are going to be needing to pump the tyres more often because they are seeping a little air out of the valve.

And they will do that whatever type of pump you use.

Oddly enough this is not a problem that I have ever had.

That isn't odd at all, it's probably something the vast majority of cyclists could say, but on the odd time it does happen it isn't a big issue and if it concerns anyone it's really simple to ensure it doesn't. I always check they're tight after having a couple on Continental tubes that weren't even finger tight, but the only time I've known one unscrew was someone else's on a group ride, it unscrewed with the dust cap. I've known more instances of people damaging the valve when labouring away with a direct fitting mini pump.