barefoot wrote:Presta valves are notoriously fragile - it's easy to rip the tube at the base of the stem, especially if you use a hand pump and you're not careful.
This happens to me more often than I'd like when changing a tube on the road using a mini pump. Is there a knack to it, better mini pumps than others or am I just rushing it
Yes, yes, and yes, to answer your questions
Well, the "knack" is just to avoid putting ANY force on the valve stem. If I have to use a conventional minipump, I try to grip the pump and the rim, braced together, to avoid wiggling the valve stem.
As Baudman has mentioned, a mini-pump with a hose is a good thing. The hose flexes to take up any movement of the pump relative to the valve, without loading the valve. I use a (cheap copy of) this mini-pump:http://www.cellbikes.com.au/Topeak-Road ... mp-w-Gauge
It does the job quite well... basically turns into a micro-sized track pump.
I'm not a big fan of Presta valves in general. Much to the distain of more "pro" cyclists, I have refused to use the fool things on my MTBs for years. I drill the rims out and use Schrader valves. It takes a different level of ham-fistedness to rip a schrader valve off the tube
and if a rim is too narrow to drill out to 9mm for a Schrader valve, it's not a rim I want anything to do with. That said, I have successfully drilled a few MTB rims that are narrower than most road rims.
I would do the same with road rims, but some in my wheel collection are fairly deep section, so a Schrader valve wouldn't be long enough to poke through. So I've come to an uneasy truce, standardising on Schrader for 26" wheels and long-stem Presta for all 700c. And I've learnt to be vewwy vewwy careful with those silly little roadie valves.