Andrew’s TT bike

Andrew’s TT bike

Andrew is my teammate here at English Cycles – we spent a lot of rides discussing his TT build, and then I spent a lot of time thinking about how best to achieve how we wanted it to be. My TT Mk 2 bike went all in with integration, which made for a very sleek build, but it was very challenging to fabricate, uses a lot of fully custom parts and is not the easiest bike to work on – which is fine for it being my personal machine, but I have been trying to get as close as I can to that bike but with a more user-friendly design. This is mainly involving the front end of the bike, trying to make the fork/frame/stem as seamless as possible. With Edd’s and Stewart’s builds, I used a small diameter (25mm) steerer tube and custom upper headset bearing, with everything secured by pinch bolts at the fork crown. This worked well, but I wanted to remove that exposed lower bearing cup and the bolts. It would also be useful to have an 1-1/8″ steerer to give more fork options.

I worked on this design concept for a while before landing on the solution used for Andrew’s frame. FSA make a headset with the bearings integrated into the cup – this allows for a smaller diameter headtube than with a regular 44mm Inset headset. I then modified the cups so that they would sit fully inside the headtube, and machined the headtube to match. The crown of the Columbus Tusk Aero fork then mates cleanly up to the bottom of the headtube. The top of the headtube is dropped relative to the toptube, to allow the stem to flow smoothly along the same line. I machined a clamping collar for the steerer that is preloaded with a regular topcap, and then secured with two pinch bolts. The special stem/bar assembly then slides over the top, and is locked in place with an internal wedge that is accessed from underneath the stem. With this design there is room inside the stem, above the topcap, for the rear brake cable to run through, and enter into the frame from the back of the stem.

I have worked with Andrew on his position over the last couple of years – he has gotten used to a narrow aerobar position and has his fit nicely dialled, so I didn’t need to build in much adjustment. The central tower that connects the basebar to the aerobar is slightly oversize so that it has room inside for a (slightly modified) SRAM eTap blipbox. To allow access to this, the upper aerobar assembly bolts onto the tower. Sockets on this upper piece allow for using any standard extension – Andrew likes the 50 degree USE version. There are bosses for a set of modified Fibre-flyte carbon armrests to bolt in place. The basebar is completed with full internal cable routing and custom machined barend plugs.

For the rear of the bike, Andrew opted for the heavier but true-NACA-profile seatmast. To give some saddle adjustment I fabricated a mini-seatpost that is secured by an internal wedge and two rear positioned setscrews. There is a cutout for the rear wheel, and – just to get obsessive with the details – the bottle bosses are brazed internally leaving the tube clean when a bottle isn’t being used. To ensure that any size tire can be set to sit tight to the cutout, there are adjustable eccentric dropouts, that utilise a ‘thru-skewer’ to secure a regular rear wheel.

Andrew really wanted the front brake mounted on the rear of the fork, so we have a TRP model there. The rear brake is a TriRig Omega positioned underneath the chainstays. This bike is intended for flat TTs only, so the drivetrain is 1x, with a Fibre-flyte 58T ring mounted to a Vision Metron aero crankset. SRAM eTap provides the shifting at the rear. Speedplay Zero Aero pedals and a Fizik TT saddle finish things off.

Just aerobar pads to be added…. The bike weighs in at 21lbs, and the paint is by Colorworks.

 

 

 

3 Comments

  1. Absolutely incredible! A total work of functional art!

  2. Whilst you couldn’t do much with routing the front brake, I think you went bonkers with the rear

  3. Wow. What a bike.

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