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Hello all, just wondering if anybody else has had the same problem that I have at the moment. I have a Schrader to presta adapter which I can screw on to the presta falve fine put as soon as I attach a pump, be it a track pump or a normal pump it just loses loads of air! I have tried different pumps but still no joy. I decided enough was enough and bought a new adapter tonight, got it home and same thing happened. I got them both from the same shop and am feeling like they are selling me stock left over from april fools day. Are they meant to come with a small rubber o ring as my mates adapter has one, the two I have do not. Would it make any difference? If all fails I am going to buy a drill and drill my rims for Schrader valves. Please help me first though as I have loads of presta tubes as spares! Cheers
this might be bolleaux as a photo would help but
- mine has a rubber seal
- are you locking the schrader on to the presta (ie using the scharder valve cam -if I leave mine uncammed it blows air all over the place)
It is just a small brass adapter which I screw onto the presta valve, I then screw my normal pump onto this. When using my track pump i again screw the adapter on and then attach the pump then move the lever to tighten it up at this point the air rushes out.
mmm - still no clearer, anyway.
mmmm - I think you are mismatching components. I have a old fashioed hand pump (handle/up and down in small cylinder job - no levers - you know old codger on bike long metal job - type that fits between two sticky out pins on a frame ). It comes with a rubber bit that screws into the end of the pump and the other end screws onto a schrader. I **think** the bit you are talking about is designed to fit on here to convert this to a presta (I have one of these and it works) - you screw it onto the rubber bit end and it 'changes' it from scharder to presta.
It sounds like you're trying to use it on a track pump - I have one it has a schrader head - and chained to that is a (much larger) adapter that can be cam locked to the schrader fitting to turn it into a presta.
It shuld work on the normal pump with a flexi rubber screw fit. On the track pump I doubt it. I * THINK**** that the isssue is that when you use the cam thta pushes a pin forwards (on a schrader this would be to compress the valve core) and it sounds like thta it hitting the presta relesae but that there is not a good enough fit somewhere.
My guess it that that you need a track pump specific adapter (OR use lots of tape etc to fix the seal that is leaking ?????????
.
I have had both types of adaptors in the past. The brass ones dont tend to work as well because of no seal. I did have an alloy one with a small seal where it screws onto the presta valve and these work much better.
I guess its just a case of hunting around to find one with a seal.
check the link below
[url= http://www.shopwiki.com/presta+valve+adapter ]presta to schrader adaptor[/url]
[url= http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170345385525 ]or this on ebay with a seal[/url]