Broken presta valve
 

Hi, I bought a new mini pump today but when I took it off the valve the nut and part of the threaded bit broke off the inner tube presta valve. It's not leaking but should I replace the inner tube or can I still use and pump it?

It'll be fine until you let air out of it or you get a flat. Then toss it.

You'll even be able to top it up but once the air pressure inside falls to zero the left over part of the pin and the seal will fall into the tube and you'll HAVE to change it.

But for now it's OK.

If you do leave it until you get a flat then I'd suggest you only pump up the tire with the stem upwards and pointed down so the valve seal tends to stay in the valve body.

Thanks for the advice, think I'd better be gentler in future! These presta valves are flimsy!

The real problem is the pump. Mini pumps are notorious for killing valves. Since I finally shelled out for a stand pump, I have replaced exactly one tube on my 4 bikes. Minis technically are only for emergencies.

Only for emergencies?

When you bring home a mini pump, you still have to test them out to know they will work when you really need them.

Are these type of pumps bad also for Schraeder valves?

It's a lot harder to damage a Schraeder valve.

Not strictly true about having to replace the tube if the valve falls out of the stem... I've successfully "felt" the pin back into place and pumped up the tube again. Also, I think your last paragraph meant to read "you only pump up the tire with the stem pointed down so the valve seal tends to stay..."

But... best to get a new tube. Five or six dollars (if that) is best spent rather than anxious energy on whether you actually will be able to pump up a flat tyre again (well, you'll be able to pump it up, but it won't stay inflated).

Not really. They are very vulnerable to cutting the rubber wrapping the stem...especially with a minipump.

Right on both counts. I was probably thinking the valve up at the top SO it's pointed down and started typing in shorthand... :D But I felt that by the time it falls into the stem or even right into the tube it's time to cut the loses and install a new tube.... but frugal is good too.... :D

I can't say that I've had any trouble with any of my own mini pumps but I did have one valve right out of the box that was bent way over to the side. It broke while trying to straighten it so it got cut up to use as chain stay wrapping, inner tube bands and other handy shop material uses.