I have a Zefal track pump, and want to pump tyres with presta valves. The basic outlet on the pump is for Schrader type valves but it came with an adapter which fitted into the Schrader outlet, and had a rubber insert within it which sealed onto the Presta thread. Unfortunately the rubber has worn over the years and needs replacing. But all the bike shops I try now offer me a small brass adapter which just screws onto the Presta thread, with the other end going into the Schrader outlet of the pump. There is no rubber and the seal between the bare threads is poor so that I seem to let out more air than I put in!
Does anyone know a source of a better adapter? Since I need two hands to work the pump, I would ideally like something which doesn't need another person to hold it on the valve while pumping. Surely this is not an uncommon requirement,, but the bike shops don't seem to have ideas.
...offer me a small brass adapter which just screws onto the Presta thread, with the other end going into the Schrader outlet of the pump. There is no rubber and the seal between the bare threads is poor so that I seem to let out more air than I put in!
How about winding a couple of wraps of white PTFE plumbers' tape around the adaptor thread where the Schrader clamps around it?
David Miles <[email hidden]> wrote in :"]news:[email hidden]:
Quoted message said:
I have a Zefal track pump, and want to pump tyres with presta valves. The basic outlet on the pump is for Schrader type valves but it came with an adapter which fitted into the Schrader outlet, and had a rubber insert within it which sealed onto the Presta thread. Unfortunately the rubber has worn over the years and needs replacing. But all the bike shops I try now offer me a small brass adapter which just screws onto the Presta thread, with the other end going into the Schrader outlet of the pump. There is no rubber and the seal between the bare threads is poor so that I seem to let out more air than I put in!
Does anyone know a source of a better adapter? Since I need two hands to work the pump, I would ideally like something which doesn't need another person to hold it on the valve while pumping. Surely this is not an uncommon requirement,, but the bike shops don't seem to have ideas.
But you do have to cut off the old adapter, which may not be what you want to do. If not, there are also some other adapters listed on that page, but no idea what they are like.
Unfortunately the rubber has worn over the years and needs replacing.
Worn, or gone hard? If it's just gone hard you might be able to resuscitate it by soaking it in DOT4 brake fluid.
-- Guy === I wonder if you wouldn't mind piecing out our imperfections with your thoughts; and while you're about it perhaps you could think when we talk of bicycles, that you see them printing their proud wheels i' the receiving earth; thanks awfully.
I got one from SJS Cycles* with an O-ring. It works (I just have one so I can use garages in emergencies) - but I reckon changing the pump head will be better. Chop it off and connect a new one. Any brand should do if the hose diameter is appropriate. A _good_ bike shop should be able to help you there, or.......
* sjscycles.comvIndex.htmOpen ↗ - adaptors £1.99, also do Silca heads - ok except has tendency to slip so requires pushing on v firmly
but I reckon changing the pump head will be better.
And I reckon he's right. A twin-head or works-on-both head is miles better than using adapters IME. I've found that adapters are far better at producing those conditions where "pumping the tyre up" lets out more air than it puts in...
Pete.
-- Peter Clinch University of Dundee Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net [email hidden] dundee.ac.uk~pjclinchOpen ↗
David Miles <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:
I have a Zefal track pump, and want to pump tyres with presta valves. The basic outlet on the pump is for Schrader type valves but it came with an adapter which fitted into the Schrader outlet, and had a rubber insert within it which sealed onto the Presta thread.
[...]
Quoted message said:
Does anyone know a source of a better adapter?
Topeak Twinhead. Got mine from the CTC online shop. Comes complete with hose: I just unscrewed the one already on my Zefal pump and replaced it with the Topeak one. Does away with any extraneous adaptors, it's a push fit onto either schraeder or presta valves. Works fine for me.
Thanks to everyone for such prompt replies. I couldn't find an adaptor at the CTC online shop, but I've ordered the Twin Head from Dyason. Everyone seems to think two heads are better than one (adaptor!)
David Miles said:
I have a Zefal track pump, and want to pump tyres with presta valves. The basic outlet on the pump is for Schrader type valves but it came with an adapter which fitted into the Schrader outlet, and had a rubber insert within it which sealed onto the Presta thread. Unfortunately the rubber has worn over the years and needs replacing. But all the bike shops I try now offer me a small brass adapter which just screws onto the Presta thread, with the other end going into the Schrader outlet of the pump. There is no rubber and the seal between the bare threads is poor so that I seem to let out more air than I put in!
Does anyone know a source of a better adapter? Since I need two hands to work the pump, I would ideally like something which doesn't need another person to hold it on the valve while pumping. Surely this is not an uncommon requirement,, but the bike shops don't seem to have ideas.
