Edd’s TT fuselage

Edd wanted a TT frame along the lines of my Mark 2. However, the front end on my bike was very difficult to build, and not very easy for user-serviceability – not a problem for a bike that is staying at EC HQ, but I needed to come up with something that would resolve both those issues, but maintain the narrow front end and clean lines from stem to toptube.

The result features a custom narrow upper headset bearing that fits directly into the machined headtube, with a standard 1″ external cup lower bearing. The steerer is actually 25mm here, integrated into the stem/bar and being clamped at the fork crown (a ‘bottom cap’ is used for headset preload). There is then a section of airfoil tubing behind the headtube to join to the toptube.

The rear of the bike has a more familiar layout, with an ovalised integrated seatmast with custom cap, dropped seatstays and s-bend chainstays.

Brakes front and rear are TriRig Omega. For the rear brake there is a custom guide on the BB shell for direct internal cable routing. The front brake cable is feed directly from an internal guide brazed into the stem/bar.

I used the old Klein term of ‘fuselage’ instead of frameset as Edd asked me to build him a custom cockpit too. He wanted the basebar to be at the level of the toptube, with a central spacer up to the aerobar – this allows for a slightly higher bar position when required for longer events (12 hour time trials are a standard event in the UK) by changing the spacer. The central spacer is made from airfoil section tubing, as is the basebar and the bridge between the extension clamps. Edd supplied the carbon extensions and arm rests – there is allowance for adjusting reach and width.

The paint is by Colorworks, featuring a bright orange stripe up the rear of the seatstays and seatmast for extra visibility on the roads. Photos by Tina Buescher.

2 Comments

  1. Just perfect…
    Where did you get such a narrow bearing? Or do the rollers actually roll on the surface of the headtube itself?

    • I just found a thin-section radial bearing – in this case 25x32x4 if I recall correctly. The top headset bearing sees very little loading, so as long as there is an angular contact unit at the lower race, a radial bearing is fine at the top.
      thanks, Rob.

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