Prototype.

11 06 2019

Well, the first prototype was ok, but by the time I was nearly finished, I was pretty sure I could make a better version. So it goes with prototypes.

Rewind. The need. Bikepacking with a bar harness, over the years, has been made much better by efforts to make the harness have 4 points of mounting. The potential problem: some handlebars don’t like having clamps beside the stem clamp, either because of the material (carbon bars occasionally need metal reinforcement at the stem clamp and the manufacturers won’t allow clamping to non reinforced areas). or because of the shape (alt bars, I’m looking at you). The solution: make a steerer mounted clamp that will deliver an auxiliary bar, ideally below, the handlebar. Boom, 4 points of mounting.

If the mounting points are fairly spread and wide and the load is not too heavy you could get away with a very light clamp as the secondary, non weight bearing part.

Fast forward to prototype 1: aluminium steerer spacer, 20mm high, 2 acetal rods and a carbon fibre tube. Can mount below or potentially above the stem. Issue? fugliness. Other issue? amount of steerer real estate.

Prototype 2 will be considerably more svelte. This is achieved because a lightbulb went on and I realised I could make a strap system between the handlebar and the auxiliary bar that means it doesn’t actually have to have any inherent rigidity, other than a slight offset to clear the head tube.

Some initial sketches gave way to lots of beard stroking about how I was going to make the offsets. Initially i’d thought to mount a carbon fibre tube ahead of the steerer and make some straps that would have a carbon fibre strip sewn into them, then around a second carbon tube.

In making the initial aluminium steerer spacer, I decided to change tack and instead of bolting a carrier to the front of the steerer spacer, bolt to the side, slightly offset with spacers and have 2 metal struts (in this case I will be using a downhill, direct mount ‘riser’ kit). these will then have the auxiliary bar attached, though again, I’m not absolutely 100% sure how so far.

Getting there…