fenester

I just started using presta valves (new bike), and I got one of the brass presta>schrader adapters to screw onto the presta stems so I can keep using my schrader floor pump.

Problem: For the life of me I can't get the adapter to screw onto the presta valve stems. All my searches just said "...and you screw the adapter on..."
So what gives?

I've tried it with the presta valve screwed all the way open and halfway open. I've made sure the presta seal wasn't stuck (although that hasn't even been an issue yet since I can't get the adapter installed).

I've tried screwing the adapter on upside down, and it screws on just fine then, but that presents the wide end of the adapter to the pump so it doesn't fit.

I'm sure there's something totally obvious I'm missing, and yes I have opposable thumbs.

Thanks,
fen.

well biked

Hmmm, all I can say is to completely loosen the presta valve, and firmly push the adapter down on to the presta valve to make sure the threads can get enough bite to start. Once you get the threads started, just snug the adapter down, don't overtighten it, the little rubber seal on the adapter will take care of that. If you've got a good adapter, it shouldn't be a problem at all-

DevilsGT2

When the seal hits the threads, start screwing it in, but push down at the same time. Like screwing on a really squishy nut.

fenester

Ok, thanks folks! I guess I just wasn't pushing on it enough. I'll post back after trying it tonight.

cheers,
fen.

Al1943

I better solution would be to replace the chuck on your pump, easily done. You can install a new chuck that will work with presta or schrader, much faster and easier than using an adaptor.

Al

AndrewP

That is how the adapter is supposed to go on, Schrader valves are fatter than Presta valves. Perhaps you already have a Presta pump.

BigBlueToe

The wide side of the adapter goes on over the Presta valve. There's a little rubber O-ring to help seal. I'm guessing that it's resisting - you have to push the adaptor on past the O-ring so the threads will start to engage. I have one of these I've been using for years with no problems. I bought a new one so I'd have a spare. The first time I used it I felt the same resistance it sounds like you're experiencing.

If you carry the adapter with you, you can use gas station pumps if you happen to flat near a gas station. I did that once when I discovered I'd left my frame pump at home. But be careful! A gas station compressor can explode your tire in no time. Give it a quick "goose" of air (1//2 second), then check the pressure.

fenester

Hi, thanks again for all the responses.

Al1943: I will probably do that (replace fitting on pump) or just get a new pump (this one is 20 years old and crappy). The adapter was just a cheap quick fix for home fillings, but also a backup for emergency fillings.

So, I did just have to push harder to get past the O-ring type seal. Because I was new to the Presta valves I was reluctant to use the "hammer" approach, so thanks for the reassurance. Working like a charm.

Cheers and Happy New Year to everyone,
Fen.

Al1943

[QUOTE=fenester
or just get a new pump (this one is 20 years old and crappy).
[/QUOTE]

I did a cheap restoration on my old pump and kept it as a backup. If yours has a built-in gauge it may be worth keeping.

Al

dedhed

Just an FYI, I had one that apparently did not get threaded inside when it was made. Drove me nuts for a number of weeks as it wouldn't thread on. I finally took a close look at it and saw the problem. LBS replaced it no problem.