nycbianchi

I recently purchased a Peloton stationary bike and immediately replaced the stock pedals with KEO pedals to match my cycling shoes. I was struck by how heavy the stock pedals were: big chunks of metal that felt like dumbells. As it happened I replaced them with some old carbon pedals which felt insanely light by comparison.

So here's the question: will lighter pedals improve my score / rankings on the various Peloton metrics which track output (as measured by cadence x flywheel resistance)? Do I have an unfair advantage when comparing scores with others?

I was debating this with my friend, @Mr_Super_Socks. He believes that -- assuming the pedals are perfectly offset and that the friction is negligible -- heavier pedals should not have any net effect on the score/effort. Although they may be harder to get going, they will have more intertia and spin longer without effort. I believe that the constant speeding up and slowing-down of a high-intensity class favors the lighter pedals.

Any physics nerds out there who can help us settle the argument?

Wildwood 

You are both right.
Negligible effect, only when accelerating - splitting blonde hairs with this thread. Unless they were flat pedals, then your clipless should allow better spinning at higher cadence.

wphamilton

I don't know how "various Peloton metrics" are scored, but in general I'd tend to agree with your friend that the heavier pedals will not be a disadvantage on the stationary bike.

jwh20

I've not inspected a Peloton up close but I suspect it, as with most other stationary bikes, has a large and heavy flywheel. I am sure that the mass of the flywheel dwarfs the mass of the pedals. So from a theoretical viewpoint, yes, the heavier pedals will impact your ability to accelerate. But I am sure from a human-viewpoint, the different is going to be of no consequence since the mass of the bike's built-in flywheel dominates here.

Technically speaking, we have Newton's equation: F= ma, F is the force required to accelerate the flywheel, m is the mass of the system, and a is the acceleration you're attempting to achieve. Obviously if m is larger it requires more force to achieve the same acceleration.