[Nemo]

Gear drives are cool, and I'm reading the discussion on axle choices carefully. Cool discussion.

I'm with Chris on the axles. For the wheels, 1/2" tube axles seem like the easiest, cheapest, best option to me.

For the idler gears, I'd personally be looking at raising them higher than the line of the wheel axles for some extra resistance to bending about the front-back axis of those wheel channels. One could use the WCP 48T dog gear with round 1/2" bearings and tube axles. For fun, I sketched that in CAD using the same wheel spacing, and the bigger idler gears would end up in a line 1.31" above the line of the wheel axles. That would fundamentally alter the design, though, because then the gears stick up 1/2" above the wheels.

Personally, I think it would be really cool to build a gear drive. Chains are pretty annoying. If I added up all of the time we've spent messing around with chains in the past couple of years, it would be quite a few hours.

Thanks for sharing this very cool project.