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presta valve extenders....(3 posts)

presta valve extenders....Oldtrott
Aug 27, 2003 9:21 AM
Thinking I needed to spend more money, I decided to buy a second floor pump -- one for the car, one for the house...

I bought a silca model that the LBS recommended. When I got it home, I found that it didn't seem to like the short presta valves in my tubular tires. It didn't work at all. A smart person would have taken the pump back but....I decided to get valve extenders. I bought the two valve extenders and put them on. Pump still didn't work - pumped air but nothing into the tire.

So, I decided to use my old trusty Blackburn pump and it successfully pumped up the tires albeit, it now seemed to have some issues with the valve extenders - readings weren't holding steady like they used to. Worse, the tires seem to deflate significantly over a 2-3 hour period.

Questions...I removed the old stems and put on the extenders but I didn't apply sealent to the extender before putting this on. Is this why the tires are leaking?

Or are extenders a bad idea?

And are the tires pretty much ruined - even if I put back the original stem will they no longer hold air like they used to?

Any help with this is greatly appreciated.

My fear is that I have a useless tire pump (silca), useless valve extenders and ruined tires...
re: presta valve extenders.... (more pumps than the law allows)Akirasho
Aug 27, 2003 7:56 PM
... can't comment directly on your problems with the Silca... I use Blackburn pumps.

1: Why are you using extenders (I'd only use 'em if absolutely necessary)? Does your rim depth require the use of said? You can find tubes with longer stems that work with all but very deep aero rims. There are at least three types of extenders... regular extenders, extenders that accept removable valve cores and extenders with their own valve cores built in. Make sure that if you're using extenders on stems with valve cores... that said cores are open (it's possible to close the valve unless you're reasonably careful while installing the extender) after extenders are applied... I add a bit of teflon tape and a drop of Blue Loctite (very sparingly and carefully to the teflon tape) to cut down on leaks (some extenders use small O rings). Thus, extenders are a good idea if needed.

2: The (tubes) should be ok if all you did was swap around extenders... unless some damage occured while doing said (pinch, pin hole, damage at stem seat). It's possible that you've got a bad or sticking presta valve. Since the tubes are responsible for carrying air (the tire only restricts expansion) I can't imagine where the extenders would ruin tires...

Good luck.

Be the bike.
Aug 28, 2003 11:02 PM
Check to see if the tires have removable valve cores. They may have been loosened somehow when the extenders were installed.

I have an ancient Silca pump and have had no troubles inflating Presta valved tubes, even with very little stem showing. Check to make certain that the rubber seal of the head is placed for Presta. The smaller hole should face out such that a seal is made as soon as the valve stem is inserted, not when the valve is in approx 5mm.