Snapping valve core/iinners

thetoecutter

Hi Forum,
I have problems pumping up tyres. It's a bit embarrassing as this is such a basic thing. I pump my tyres before every ride and I keep snapping the valve cores or iinners whatever they are called.
So far in 18 months I reckon I have snapped about 6 to 8 on 4 different wheel sets using different inner tubes, continental and vavert .
Is it my technique? I use a track pump and I notice that I always have to let out air otherwise the pump bounces and I can't get any air in. Even if I do let out air, often it still happens. If I get past this sometimes it will be hard to pump until there is a pop or release of pressure and then it will finally work.
Is this normal?

cooldad

Sounds like a faulty pump.

cougie

It's your technique. I've never snapped one yet. You want to remove the nozzle vertically off the valve rather than to the side.

thetoecutter

Cooldad I will look at the pump, but it is a decent one, I think, it's a park tools. I haven't tried another pump, except the car foot pump, which has never given me trouble, but the pressure valve on that is unreliable.
Cougie I think the first few would have been due to bad technique I noticed the cores were bent and then snapped, so I have been making a conscious effort to make sure I do remove the pump vertically without twisting, and the problem persists.

fenix

Try knocking it off the valve with a sharp tap in the same direction as the valve points. (you are unlocking the pump lever arent you ?)

thetoecutter

Fenix I've not tried that technique of tapping the pump head so I will give it a go. Yes I made the mistake first time of forgetting to unlock it, but never since then.

keef66

I've occasionally bent one, but never had one snap.

I always unscrew the valve and give it a press to release a bit of air before attaching the pump head.

Make sure the pump head is going on dead straight and the valve is properly inserted before locking it on. You'll feel a bit of resistance on the first stroke of the pump but it should be easy after that.

And as already mentioned, when you unlock the pump head, try to take the thing off again absolutely straight.

If you continue to have problems, maybe you should consider a screw-on head for your pump? My Lezyne mini pump has one, and the hose also has a pressure release valve which makes unscrewing it easier.

paul_onabike

I had this problem with a park pump.
I ended up screwing a presta to schrader valve adaptor onto the valve, and using the schrader part of the pump head. Solved the constant bending of valve stems problem, and gives a much better air seal around the valve. I bought 5 adapters off ebay for £3 or £4 .
It only takes about 10 seconds longer to blow your tyres up.

thetoecutter

Thanks keef66 and paulonabike I have a valve adapter for the car foot pump, never thought of using it. I will try it and I also have a lezayne mini pump to keep with me when out, just realised, after you mentioned it, that I've never had a problem with that.
I think it may be the pump.

sungod

you could try fitting a different pump head...

https://www.sjscycles.co.uk/pumps/sks-e ... pump-head/

i have a lightweight lezyne track pump i take when i'm cycling overseas, but the head was useless, swapped it for one of these, it's perfect