I wanted to lower the front of my bike and get a more aggressive aero position. Doing that on a road bike can sometimes be difficult as the head tube is a bit longer than on a tri bike. Once I'd gone to the bottom of the steerer tube I still wanted to go lower. I put the tribars on the bottom section of the Carbon X base bar but that leaves the armrests really high and means you have to ride with your wrists at an angle, something I didn't want to do for an Ironman race. So I wanted to mount the armrests directly to the base bar and get rid of that top tribar clamp. That would lower the armrests by about 15mm. Unfortunately Profile didn't design the bars to take the clamp out so some modifications are needed.

First thing to do is remove the top clamp and put one of the long bolts through the hole in the armrest mount that is used to mount it to the top clamp. Put the bolt/mount through the inner drilling on the base bar and lightly tighten it up. Put an allen key through the other hole so it positions itself correctly.

If you then bolt the armrest to the mount you'll see you need to drill a new hole in the armrest to straighten it up. Carefully choose the position you want using one of the holes then tighten it down so it doesn't move. Remove the armrest mount with the armrest still attached. Poke a sharp nail through the other armrest mount hole and scratch the position onto the armrest. Take it all apart and drill a hole where the scratch is. If you get the position slightly wrong you might have to ovalise the other hole a little to get some positioning movement back.

Tidy up the drilling with a file and take off all the bur. If you do one armrest at a time you can compare position to the other one to make sure you get it in the right place.

Next you need to enlarge the inner armrest mount hole on the armrest mount. This is because the drillings on the base bar are a bit wider than the standard drillings on the armrest mount and the bolt is bigger. As far as I know, you can't get hold of replacement armrest mounts so this is the point where you need to consider your skill with a drill!

You want to get the new drilling to line up with the holes in the bottom clamp so have the bottom clamp and the two long bolts handy and keep checking your progress. If you use a Dremel type grinding tool, don't put it close to your face as breathing in aluminium filings isn't good for aerobic capacity!

Once it lines up, tidy up the hole with a file.

Finally, offer it up to the base bar and very loosely tighten it up. If your happy with the position take it off again and put washers under the armrest clamp. You may need to put a couple under the outer drilling to level it out.

Even if you chose not to put washers under the mount bar to level it out you must put a washer between the mount bar and the carbon base bar, do not clamp directly onto the carbon.

You can put the mount bar either pointing forwards (as in the picture) or backwards depending on where you want the pads positioned.

Now tighten it all up and test out the position. You may have to put a couple of washers under the armrest clamp to get it clear of the outer long bolt that goes through the base bar.

Here is the finished job, you can see how it's now about 15mm lower and the washers in place to level it out. Everything looks a lot tidier. Shame Profile don't make a kit for it.

Obviously you do all this entirely at your own risk (should have said that at the start really!). Keep offering the bits up to the bike to make sure you're doing the right thing. One side mirrors the other so don't just drill out the 'left' hole on the armrest. You can get replacement armrests so it's only the armrest mount that needs very careful attention.