Presta valves

[youngoldbloke]

Me too, surprised when tyre deflated when I removed dust cap (yellow - Continental?). Valve core had loosened and unscrewed with the dust cap. On close inspection found flats on the core, so easy job to tighten it - used miniature adjustable spanner!

 

[youngoldbloke]

Yes, as you put the pump on the valve it was being pushed up into the tyre so not enough was in the pump head to engage properly. Put your thumb on the outside ow the tyre to hold the valve still when putting the pump on. Once it has pressure in it will be held in the right place.

+1 (seems we've been talking about two different issues in this thread). If your valve has a locknut it serves the same purpose as the thumb, holding the valve out. You will need to do it up more once the pressure builds up. Of course some presta valves do not have lockrings.

 

[Cubist]

+1 (seems we've been talking about two different issues in this thread). If your valve has a locknut it serves the same purpose as the thumb, holding the valve out. You will need to do it up more once the pressure builds up. Of course some presta valves do not have lockrings.

Surely they are wasted valuable grams and need to be thrown away? Same with the dust caps.

 

[youngoldbloke]

Surely they are wasted valuable grams and need to be thrown away? Same with the dust caps.

Too true - remove them and dispose of in an environmentally friendly fashion, after re/inflation. On group rides arrange a rota for the carrying of the shared lockring. If riding alone only one lockring is needed - carried in your (suitably minimal) sadddle pack. Leaving them on may also upset the balance of your cheap wheels too. Of course, really expensive wheels will come finely tuned to allow for the weight of the valve.

(earlier post edited as dustcaps are, as Cubist points out, totally pointless, and add unwanted grams, although I do like the flash of yellow provided by the Conti ones ...... especially on black rimmed wheels.)

 

[Paulus]

If you wanted dust caps, but lose a bit of weight, could you not trim the lower edge of the cap so that it just screws onto the valve with one turn, enough to hold it in place? Nothing wrong with a bit of bling on the bike!

 

[youngoldbloke]

No - I'm prepared to sacrifice the bling in the cause of saving a fraction of a gram - it all adds up you know !

 

[DougieAB]

Had a tube recently where the valve core unscrewed when you unscrewed the cap and lost all the air. Tightened up core and was ok after that.

 

[mangid]

I've had this recently with Continental tubes

Yep, happened to me twice with Continentals in sub zero temperatures. Pumped it up, unscrewed hose, valve came out, put it back together, unscrewed, valve came out. Gave up and got another new tube out, lots of choice words being muttered.

 

[lulubel]

I had some of the dodgy Contis. They're easy enough to tighten with pliers, but not very helpful if you're changing it at the side of the road and you haven't done it in advance.

 

[Grizzly]

With regards to inflating, get one of these, no more bent valves or pumps falling off.

 

[youngoldbloke]

Don't remove your push-on pump chuck with a karate chop - that's the sure way to bend and break the valve. Ease it off with your thumbs either side of the rim pushing towards the hub. At home, I recommend using a brass Topeak Super Chuck with your track pump. +1 for the mini pumps with hose. The Lezyne ones are highly recommended too.

 

[screenman]

Surely everybody uses a bit of lubricant before putting the pump on the valve, thus helping it slide on and off easier..

 

[byegad]

Yet another reason I prefer Schrader. One of my trikes ha them and with aero rims drilling for Schrader is not on. I hate the damn things.

 

[the_mikey]

Once had a continental valve core fire out of the rim like a bullet, never saw it again, took one from a spare tube and learned to check them regularly!

 

[mangid]

With regards to inflating, get one of these, no more bent valves or pumps falling off.

The Lezyne pumps are pretty good, apart from their ability to unscrew the Conti presta valve I guess ;-)

http://www.wiggle.co.uk/lezyne-road-drive-mini-abs-pump/

Used use a Zefal HP pump, but had no end of bent valve.