I've about had it with threaded presta stem tubes. I have had more of these tubes fail at the joint between stem and tube. I've tried both without the lock-nut and with the lock-nut, different brands, different pressures and all the same result. I have not had any problems out of the unthreaded presta stem variety.
This presents a unique problem. When trying to locate tubes that have unthreaded presta stems it's a [censored] shoot. Some do, some don't. I've had the most luck with Kendas but I was wondering if anyone out there knew of any others that offered specifically unthreaded presta stems on road tubes (700x23).
i am curious because i havent had such problems. what kind of rims are you using? i run mavic ma40's and have used wolber alpines before, and have never had a problem. i was wondering if you are running some sort of areo rim or something that might be causing this, or perhaps when inflating you are damaging them in some way by twisting or pulling on them too much.
I have broken a couple of Presta stems trying for the last 10 psi with my mini pump. But I have also torn a couple shraeder valves out of the tube doing the same thing.
i guess i am at a loss, because it hasnt been an issue for me. i know that all of the long stem tubes i have bought from Nashbar have been threadless so far. i suppose because they are for deep-v rims. i bought a bunch because they were on sale for like two bucks, and i stocked up on like ten. i still have most of them, and seem to rarely get flats. surprising seeing as i am 6'2" and 225, but it has been almost three years since my last flat. i credit contanental (sp?) tires and watching the road to avoid debris.