After reading the recent post on aerodynamics with interest, I thought I ask whether anyone has any scientific data on the power loss in transmission on a tandem.
As tandemgeek pointed out in the post on aerodynamics, the combined power of pilot and stoker delivered to the rear wheel on a tandem will never equal the sum of the individual rider's power output. The amount lost will depend on how well the riders work together. This is clearly the most significant factor in power loss on a tandem as can be seen from the fact that 2 well matched good riders can beat 2 poorly matched stronger riders. It's also evident when you take out most of the affect of aerodynamics and look at tandems up hill. A well matched pair can ride hills well but never as well as a good single bike climber.
What I'm interested in is whether anyone has looked at this affect scientifically? Or whether anyone has looked at power loss purely through transmission? My pilot has rigged his tandem up to his turbo and believes he's loosing 50-100 Wats riding on the front of the tandem as opposed to his single bike. This isn't scientific and based purely on his perceived effort but suspect there is a perceivable drop.
From the post on aerodynamics, a tandem typically experiences 130-150% of the drag of a single bike. But if you're loosing power in transmission through not riding well together, a team's total power may only be 175% or even less. Then when you consider the fact that as soon as one rider on a tandem is trying to push/pull harder than the other, they're trying to accelerate the entire bike on their own, working out of sink, no matter how little, is likely to be more fatiguing and result in a greater power loss over a even a 10 mile TT towards the end.
This is also bourne out by the results from 10/25/50 mile TT where tandems participate with single bikes.
Clearly a well matched strong team on a flat course with either a head or tail wind should be faster than any similarly matched single rider. But how often is that the case?
I think I've kind of argued that the power loss in transmission due to riders not working well together plus any mechanical loss is ultimately greater than 25% of the sum of the individual riders power?