Aerobars (especially clip-ons) take up a TON of handlebar real estate. This can leave you with little to no space to install your head-unit.

Some of these handlebars come with options for mounting computers, but many do not.

Fortunately, for about $2-5 you can make a simple (and lightweight - mine was 10 grams) mount for your computer that gets the job done, and doesn't look too shabby.

Step 1: Materials

You will need:

Short piece of 3/4" PVC pipe. 3/4" should be close to the thickness of your bars, but get whatever diameter is matches your bars. ($2.50)
2x Zipties
Sandpaper
Small saw or cutting tool (to cut the pipe to length)
Sharp hobby knife
Tape

That's it!

Step 2: Cut Your Pipe...

The real step 1 is to install your tri-bars and make sure they're spaced the way you want them. You've probably done that already.

Step 1.1 is to cut your PVC pipe. You want to cut the pipe so that it fits in the space between your bars. You want to leave a little extra because we're going to be sanding it down later. Too much extra will result in more work though, so measure (guess) carefully.

Step 3: Create Your Sanding Block.

Using the leftover pipe and sandpaper create a rounded sanding block. The pictures should be self-explanatory... but you're affixing the sandpaper to the pipe with the tape.

Step 4: Round the Ends of Your Mount

Using your rounded sanding block sand both sides of your mount until it fits snugly between your bars.

This will probably take some trial and error. Be careful not to take off too much material - you want a tight fit. We'll be taking off a little more in the next step.

Step 5: Clean It Up.

Using your hobby knife clean up the edges of your handy-work. Be VERY careful with this, these knives are incredibly sharp. You want to carve out enough plastic to allow a ziptie to fit between the bar and the tube. I recommend taking off very little material at a time, test fitting, and then taking off more until you're happy with it.