I do it because I copied some racers who looked like they new what they were doing.
Another thing I copied from the pros is taking my valve caps off. I asked a racer why he does it, and he told me that the caps are only necessary on uninflated tubes to prevent the valves from puncturing the tubes. So if you want to look pro (and I know you do), take your darn valve caps off!
racing=not, regular riding=yes. they hold the tube in place. I use them to hold tubes firm when blowing them up so as to take pressure of the seating in the tube. bouncing a pump around can tear the valve out of the tube.
Thanks. Learned a few more tricks to make me look more professional (at least, when I'm standing beside my bike at the side of the road). So, two caps and two nuts - that's oh, about 16 grams, right? Looks like I can finish the last french fry after all!
The position of the rear QR lever seems standard, but I confess I used to have my front QRL diagonally pointing upwards tucked in just along the back of the left fork tine. Anyone run it on the right side? And can anyone provide rationale for left side? (Counters weight of cassette on right side? Something to do with physics of rotational gyro forces?)
As for valves, makes sense: neither caps nor nuts are necessary to keep the air in and the tube in place.
But, on a MTB, I recommend at least the caps; it prevents mud 'n' crud from building up and clogging the valves when you adjust air pressure on the trail. Even nuts can help prevent undue grit entering rim.
Once, I fell side-ways off a rock into a bush and one of the branches sheared off the valve stem - nut and all - at the rim. Lucky I was carrying a spare and not just a patch! (Yes, I know! How would having the nut or the cap on make a difference? Well, I just thought it an unusual puncture...)
Maybe we can we can start an "Unusual Punctures" thread. Would that be an more interesting thread than valve nuts?!
At my LBS, here, in texas, you have to pay an extra two bucks a tube for a threaded valve stem, so we don't even worry about the nuts. We never see them. The tubes are some generic recycled brand.
The only difference that I noticed between the normal stems and the smooth ones is that the smooth ones rattle, which is taken care of with a little electrical tape around the bottom of the stem before you mount the tire.
The reason that I was taught for the QR lever on the let side is so that you don't mount a directional tread backwards accidentally.
Valve caps: Yes; for aesthetics. Lockrings: No; on my wheels they always come loose and generate a horrible buzzy rattle. QRs: Left side so as not to clash with the derailleur at the back and for consistency at the front, levers vertical in front of the fork / behind the seat stay where they don't clash with anything and I can get my fingers around them.
Interesting. Now that I've shifted to the "no valve cap" camp, I have come to prefer the "sleeker, meaner" look of a naked valve. Valve caps on wheels now strike me as looking kind of bulky and out of place. And they add so much weight!