Presta valve problem

[sebinho]

Hello,

On previous bikes, I've had clinchers with presta valves and have never had a problem using my "Beto" floor pump to inflate the tyres. On a new bike, I put on wheels with tubular rims and tyres (Vittoria Rally). The problem is, after loosening the nut on the valve and pressing it quickly to let out a jet of air, when I attach the pump to the valve and close the latch, air escapes as I pump. I can fill the tube with air only if I push the pump nozzle onto the valve with one hand as I pump with the other. It's really inconvenient! It's as if the pump nozzle has nothing to grip onto when its lever is fastened.

I notice that the valve is a removable one (two flat sides on the threaded section). I have tried tightening the valve with a pair of pliers (i don't have the correct tool) but it doesn't seem to help.

Might it be the pump that's the problem? Is there something else I can try?

Thanks,

 

[oldwheels]

Hello,

On previous bikes, I've had clinchers with presta valves and have never had a problem using my "Beto" floor pump to inflate the tyres. On a new bike, I put on wheels with tubular rims and tyres (Vittoria Rally). The problem is, after loosening the nut on the valve and pressing it quickly to let out a jet of air, when I attach the pump to the valve and close the latch, air escapes as I pump. I can fill the tube with air only if I push the pump nozzle onto the valve with one hand as I pump with the other. It's really inconvenient! It's as if the pump nozzle has nothing to grip onto when its lever is fastened.

I notice that the valve is a removable one (two flat sides on the threaded section). I have tried tightening the valve with a pair of pliers (i don't have the correct tool) but it doesn't seem to help.

Might it be the pump that's the problem? Is there something else I can try?

Thanks,

Do not unscrew the nut too far. Try taking it only half way or less and see what happens.

 

[sebinho]

Do not unscrew the nut too far. Try taking it only half way or less and see what happens.

Thanks, yes, I've tried that. No position of the nut helps. I'll attach a photo with nut fully unscrewed. Does anything look out of order?



Edit: The shaft on my clincher tube valves has ridges along the entire length, right to the end. The nozzle on the pump seems to grip onto this - but does not grip on to the cutaway section on the brass shaft of the tubular valve - it doesn't reach it. Perhaps the valve is not fully screwed in, which makes the distance too great.

 

[johnnyb47]

Try a different pump on it.My pump is temperamental on different tubes I use for some odd reason

 

[sebinho]

Try a different pump on it.My pump is temperamental on different tubes I use for some odd reason

Yes, it must be that. I'll see what's available at the local bike shops

 

[alicat]

It's normal to hold the pump nozzle / press the tyre as you start to inflate the tube. It just persuades the pump to stay put and the air to go into the right place.

 

[mjr]

The rubber grip in the pump head may be worn and need replacement. I'm not sure if you can get spares for Beto easily, but replacing the head with an SKS one is possible. I did that to mine.

 

[GuyBoden]

The rubber grip in the pump head may be worn and need replacement. I'm not sure if you can get spares for Beto easily, but replacing the head with an SKS one is possible. I did that to mine.

Yes, this is a common fault.

 

[simongt]

Interesting post. I've been using Presta valves for about sixty years and only had an issue once when the whole valve core came out when I released the track pump head.
Obviously I've just been lucky - !

 

[mjr]

Interesting post. I've been using Presta valves for about sixty years and only had an issue once when the whole valve core came out when I released the track pump head.
Obviously I've just been lucky - !

A spoke key can usually tighten a loose core.

 

[sebinho]

The rubber grip in the pump head may be worn and need replacement. I'm not sure if you can get spares for Beto easily, but replacing the head with an SKS one is possible. I did that to mine.

I was about to go to the shop and test some pumps but that sounds like a good idea. So this part here?:

https://www.ebay.com/itm/2557762091...=2047675&ssuid=&widget_ver=artemis&media=COPY

Is it a simple job to mount the new head?

Thanks

 

[alicat]

^^^ Yes, I swapped mine easily from a Beto to an SKS.

 

[Andy in Germany]

Interesting post. I've been using Presta valves for about sixty years and only had an issue once when the whole valve core came out when I released the track pump head.
Obviously I've just been lucky - !

I think it's the pump seal; we get Presta valves of various ages and states of repair and never had a problem.

"German" or Woods valves on the other hand...

 

[mjr]

I think it's the pump seal; we get Presta valves of various ages and states of repair and never had a problem.

"German" or Woods valves on the other hand...

Yes, the short thread on those (my weapon of choice) means I am very prompt replacing the grip washer when it wears.

 

[simongt]

Woods valves

Ahh, I mind of them well; all we had available back in t'day - !
Originally you had to replace the wee rubber sleeve / seal periodically and then some bright spark came up with a design with a built in valve seal which we could then say ta ta to having to buy valve rubber - !