This is a real gumby question but ever since i started riding road bikes/fixed I have had trouble with pumping up the tires using presta valves. I am finding that after reaching desired pressure I have a lot of trouble disengaging the pump and it involves either pulling with substantial effort or pushing then pulling it to get it off. This is obviously not good for the valve as I usually damage one every 2 months or so. Any handy tips.
This is what I do;
Unscrew valve on presta and push down to release some air
Push appropriate pumphead on and press down solidly (I find if it’s not pressed down hard then air wont enter at all) and lock latch
Pump to desired pressure
Unlock latch and try and remove.
What pump are you using? My silca can be a bitch to remove if (a) the valve stem is threaded and/or (b) the rubber insert in the pump head is new. If one or the other applies don’t just rip at the pump head or you’ll rip the valve stem out of the tube (sounds like you’ve discovered this for yourself) - try wiggling the pump head off - might help until the rubber wears a bit.
otherwise try to stick to tubes with smooth valve stems, they’re around.
What about the little nut that sits half-way up the valve? Wind that to an appropriate height, this will stop the pump head ‘swallowing’ the whole valve. Start shallow and work your way down until the head actually attaches to the valve.
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The only other thing I can think of is if you’re worried about the head of the valve getting ripped off then don’t unwind it to the end of the valve, a couple of turns will still leave you with plenty of space to get the air in, and reduce the chance of it catching on the valve head when you yoink it off. And don’t forget to cuddle afterwards.
Why do they even make presta tubes with threaded stems now.
Buggers your pump washers and stresses the stem valve join to the tube.
A good lube for your pump washer if you have threaded stems is the good old spit.l
I can understand with Shreaders running lower pressures, wher the tyre can squirm on the rim, but there’s no point to high quality tubes having treaded stems.
That’s my 5 cents worth (value increased due to inflation and experience)
Ken Ewing @ KJH Engineering in Highett is pretty chilled and doesn’t mind doing little jobs like this. Shouldn’t be hard to put the thread in the inside at all, but you wont be able to tap all the way to the top.
(03) 9532-6110
[quote=alex4point0 ]
anybody know any fitter/turners? how hard would these be to knock out? might be tricky to tap a thread on the inside rite
Turning a thread on the inside of anything shouldn’t be that hard with a tap set I would think…I learned to do it when I was doing year 10 work experience.
It only has to be airtight - wouldn’t hand tight be sufficient? Just worried about tearing out valves if it’s wound on with a key. Ever torn out a valve?
I use them on all my deep carbon roadie wheels as valves aren’t long enough. Hand tight is nowhere near tight enough to get a good seal. I use an allen key and tighten them very hard and still need to use the thin plumbing tape inside to seal them properly sometimes.
