I'm writing from France (I hope i'll make myself understood). First, thanks and congratulation for this great forum (much friendlier and wellcoming to the beginners like me than the French forums)
I'm beginning with Trad climbing, which is not as popular over here as it is in America. My questions may seem stupid to some of you but I will always prefer to sound like an idiot than die next weekend.
It seemed to me that, when a quickdraw was clipped to the wire of a nut, the karabiner sometimes tended to move up and turn because of the tension of the rope when climbing up above the pro, and thus sometimes setting the wiregate against the wire with the risk of the karabiner to open during a fall.
Is there a way to prevent this (long slings, proper placement,...)?
I hope I'll have the opportunity some day to come to America and climb your great big walls (even if I don't want to fly for ecological reasons).
If I'm reading you right, I've never had that problem, but... a longer sling might work. You might also try just flipping the top carabiner over before you climb past.
If there is concern with torque being transmitted from the rope end carabiner to the pro-end crab then use a sling between then that is not "stiff" to transmit the torque. Any nylon or spectra runner should do fine. Look up something called the "trad draw" to get an idea of this and convenient ways to use them.
sorry about the "poll" thing, I have no idea of what this is. The "system" would not let me post anything if I didn't put something in the 'poll boxes"
Extendable runners are created by connecting a biner at either end of a shoulder length sling. Pass one the biners through the other and clip the same biners through both slings. Extendable runners are extended by unclipping either biner from two of the three slings and pulling.
If you use the runner at it's full length, then the rope shouldn't be able to pull on the carabiner on the gear side of the runner. Good luck.
If you look at many quickdraws (sport or trad) many have a little rubber thing holding the carabiner in correct alinement. If your draws don't have these, then you can easily make the youself, simply take a rubber band, girth hitch it around the sling, and clip it though the carabiner, so it's circularly around the sling bit nice and tight, stopping the biner from cross-loading.
For the OP just so I add something constructive (the only thing worse than a troll is a post whore) - check out these 'Yosemite Draws' wire gate draws on Dyneema slings, they work pretty well.