This won't work. 25.4mm is the clamp
diameter of mountain (and some road) bars. The diameter of the bar itself is 23.8mm for road bars, 22.2mm for mountain bars. So, your shifter's clamp won't fit around road bars. I'm assuing you're referring to some style of thumshifters or rapidfire shifters. I'm assuing the shifters mount seperately from the brake levers. If they're integrated into one mounting clamp, it would be pretty weird to mount them on road bars.
There are only two ways you could use your flat-bar shifters, with clamp designed for 22.2mm diameter bars, on a road drop bars.
(1) if your shifters have a steel clamp that you could physically widen
(2) if you get an old chromed-steel drop bar that has a bar diameter of 22.2mm. These all had 25.4mm clamp diameter. I've got two sitting around; PM me if you want one of them. Here
's the sort of thing you're looking at. Though a steel drop bar on a nice flat-bar commuter-type bike would be strange.
You'll only be able to use a road bar with your intended-for-flat-bar stem if the stem has a clamp that totally comes off - usually hte clamp area on stems designed for flat bars is too wide to slide a curved drop-bar through. Given the bike's price, I'm guessing it does have a removable clamp-cap and this will work.
Also, if your bike has V-brakes, you'll need to get special road levers that pull more cable than standard road levers; V-brakes require more cable pull than the standard caliper/centerpull/cantilever brakes which will all work with the same levers. Or you can get standard road levers and use some kind of cable-pull adapter.
edit: juicemouse beat me to it.
Last edited by TallRider; 02-28-06 at 09:37 AM.