After almost three decades of rolling ninety degrees out of phase, we decided to make a change to just three teeth out of phase (38-tooth timing chain-rings).

We had been forced off the bike for a couple of months due to some horrid respiratory tract infections, including pneumonia for both of us, so we are doing this without our usual base of miles. We had only been back on the tandem for about 500 miles when we made the change. This seemed like the best time to do it since we wouldn't be judging it as harshly against our normal set-up.

After getting used to the odd sensations of surging with each pedal stroke and adjusting my normal extremely quiet climbing style to allow for more bike oscillation (I'm the large stoker; my wife is the small captain; her cranks now lead mine by three teeth), I'm somewhat happy with the change. On our normal forty mile 3000 feet of climbing pre-sunrise ride we were immediately almost ten percent faster. Clearly the increased speed was in the climbing where we were always one gear higher but at a similar or cadence; we descend quite slowly because of both the darkness and the large populations of deer, turkeys and foxes along our route. The bike actually felt more lively, and perhaps it was if there is something to the planing hypothesis.

It does feel like it is easier to accelerate on a climb. When we were 90 OOP, it felt a bit like pedalling into a brick wall to speed up on a climb. Now it feels more like a half-bike where one can simply put out a brief surge to add speed and it's easy to hold it.

Fun times. It will be interesting to stay with this set up as we get our fitness back over the next several months and then see what happens if we change it back. I know back when we were in our twenties when we were very strong riders we were faster OOP, but we lived in the pancake flat Sacramento Valley back then, so that may have just been a reflection of the lack of terrain.