Hi,

I've got one of those lezyne micro pumps, with the screw on hose thingy. I was using it to pump up a road tube the other day, and when I went to unscrew it it unscrewed the whole top section of the valve, letting all the air out. I tried a few more times, but every time the valve came apart, letting all the air out.

It seems there's a problem with the rubber ring thing on the hose gripping on the valve, and so unscrewing the whole thing when the hose is removed.

Anyone got any ideas how I can stop this happening again? Is it just a matter of a bit of loctite in the valve?

Cheers

Presta = shite
HTH

Stick some lube on the rubber ring

loctite or PTFE tape on the valve

actually, I don't understand – you have to unscrew the valve thingy to get any air IN. If you undo it as far as it'll go it can't undo any more…

Screw on adaptors for presta? Never seen them.

some presta valves have removeable cores, i guess this is the bit that is coming out

the whole valve core is coming out is my guess.

bit of lube ont he rubber int he pump head will help plus gettign a proper valve core tool and making sure it's done up tight.

yep that's right – it's a two-piece valve, and the hole core is coming out. Seems like a crazy design.

I'll try the lube trick. Unfortunately I didn't have any lube when this happened yesterday. Puncture 10 miles from home. Luckily a passing numpty lent me his plastic mt zefal pump, which did the job.

it allows you to replace the inherently weak valve core when you inevitably snap it

also allows you to put in sealant

a numpty? ooh get u 😯

I'm with SFB on this.
Drill the rims if necessary and fit something that won't fall apart – Schraeder valves!

🙂

prestas are fine on my mtb, it's just on the road bike. Besides, I'm not sure a schraeder would cope with 120psi

I've never ever run Schraeder valves. Seem odd technology to me. Also I've never ever had problems with Presta valves; they are much easier to inflate even apart from OP who seems to be doing something odd.

lucky you met the numpty with a working pump, oh! hang on 🙄

I've never ever run Schraeder valves… they are much easier to inflate

if you've never used the others, how would you know ? Much easier ? Easier how ? Attach pump to valve. Pump pump pump pump pump pump pump pump stop. Except I've found with Presta most of the air comes out sideways instead of going into the valve 🙁

I have had multiple presta valve cores snap off on me – maybe I am cack-handed but it's pretty annoying.

for the avoidance of doubt, numpty wasn't meant in a derogatory sense. It was just shorthand for saying he was riding a badly maintained bike, wearing tracksuit trousers and a yellow tabard.

He was a thoroughly charming chap, and saved me from a very long walk.

I've had quite a few Presta tubes wasted by the valve tearing away at the join with the rubber. Never had any similar problems with schraeder.

And don't be daft, it is definitely easier to inflate schraeder valves!

Attach pump to valve.

IF you can get it to stay on. IF you can get that sticky out bit to push the valve in. IF you can then keep the air going in instead of coming out sideways. IF you can release the adaptor without letting all the air out. Scraeder suck.

IF you can get it to stay on. IF you can get that sticky out bit to push the valve in. IF you can then keep the air going in instead of coming out sideways. IF you can release the adaptor without letting all the air out. Scraeder suck.

funny, till the penultimate word I thought you were describing Presta :o)

Really, unless you're a complete numpty or have tried using a hammer instead of a pump to inflate presta tubes, it's virtually impossible to knack them.

apparently lezyme are bringing out a new slip chuck to resolve this problem which can be retrofitted to its "older pumps"

Shraeder's a bit special needs imo.
I kinda of assume that they're for people who need a torque wrench to fit a water bottle cage 🙂

I've never ever run Schraeder valves. Seem odd technology to me

Fair enough, but 'odd technology'? Eh?
Valve, lets air in, keeps air in. What's odd about that? 😕

funny, till the penultimate word I thought you were describing Presta :o)

So did I!