Originally Posted by
69chevy
They are equally efficient. Every revolution moves the bike the same amount.
Crank deflection would show slightly more power at the crank in the smaller chain ring with a crank based meter.
A hub based pm would show slightly more power at the hub on the big chain ring.
The power difference would however be effectively zero.
There are power losses through the chain, they vary (so the drivetrain is not equally efficient in every gear), and they dwarf any error introduced by the different chainring deflections. But thanks for playing.