Team issue Time Trial Tandem

I always seem to have lots of ideas about what bike I will build for myself next – often looking to prototype new concepts or methods. But (fortunately!) I have lots of bikes to build for my customers, so it is hard to find the time. What usually happens is that an upcoming show prompts me to make one of those ideas happen. I didn’t attend NAHBS this year, but the friendly folk at Full Speed Ahead were looking for a bike to display their components, so I suggested building a time trial tandem – something I have wanted to do for ages, and very suitable to their new wireless WE groupset.

I raced a few TTs on a tandem back in the UK, and have raced tandems as both captain and stoker on the road and off-road. But a pure TT tandem has a rather limited use, so I wanted to make it convertible to a road tandem too. I was able to set the captain’s geometry so that with the low stack of the Vision TFA aerobar and the saddle forward I could match my TT position. Then with the saddle back, and a 130mm stem angled up with a spacer underneath, I could match my road position too.

To give the stoker maximum adjustment for different riders, I built a stem that mounts from the toptube which allows for free fore-aft adjustment and telescopes for height adjustment.

I wanted to carry over aero features from my TT builds, but seatmasts would limit adjustment and make it hard to pack. So I fabricated custom ovalised seattubes with matching titanium aero seatposts. This also helps with the stoker aerobar position – the narrow post allows for the extensions to come either side of the captain’s  seatpost whilst leaving hand room.

The wireless shifters of the FSA WE group make road-TT swaps easy – there is a cable splitter for the rear brake, so only the front brake cable to unclamp when swapping cockpits.

The frame features titanium mid-tubes – this serves a couple of purposes. One is that having the tubes bolt in enables easy traveling with the bike – the whole bike packs into airline checkable cases. Secondly, it allows tuning of the frame – in my experience of riding tandems, a certain amount of flex is required between captain and stoker, so that the bike can move independently a little under each rider. If required, the wall thickness of the midtubes can be varied to adjust the stiffness of the frame.

The back end of the bike features Paragon sliding dropouts. This enables the rear wheel to be tucked up precisely to the cutout on the rear seattube. It also gives the option to swap the inserts to add a disc mount. In this way the wheel can be slid back in the dropouts to accommodate a bigger tire with a disc brake for riding more diverse terrain.

For the drivetrain, I wanted to use the Vision aero cranks. But of course needed a timing chain too. I decided to use a same-side drive – this evens out the loading on the rear BB and in theory should be a little more aero keeping all the drivetrain on the same side. To make this work I machined an adapter to add a third chainring to the rear crankset. I then had to heavily manipulate the chainstay to allow for the extra clearance this required. The same adapter used on the captain’s crank allowed for the 34T timing ring and adjusted the chainline to match the rear.

Fantastic fade paint work and titanium polishing/blasting by Colorworks.
Final complete weight is just under 30lbs.

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