Last weekend I was doing a teardown and rebuild (new frame, old group). I have a Profile Century clip on TT bar which I really like. Problem is that it is not easy to mount a computer or HRM on. After a little brainstorming (and looking around my garage for what I had available) I came upon an idea.
I measured the distance inside the bars (1.5 inches). I took an old road handlebar and cut off that much from the drops. I used my grinder and sandpaper to clean up the ends (no sharp spots that could damage the bar or injure a person putting the computer on). I drilled two small holes for zip ties
and secured it that way. Very light and fits perfect. I have one for the computer and one for the HRM and still have space for a can of HALT! I can see everything perfectly in TT position. Cool beans!
I have also used PVC but the dark anodized color fits the bar perfectly. Either bit works, though and is a heck of a lot cheaper than the plastic mount that Profile and other makers sell for their bars ($10 or so, from what I have seen).