SheldonBrownBlog

The Gear Calculator has now been upgraded to allow entry of data from a rollout measurement.

We have upgraded and updated the Gear Calculator.

Our gear-graph article now includes a new, much improved version by Jeremy Mak of the diagram which plots gear ratios of bicycle cassettes and freewheels.

On our page https://sheldonbrown.com/flats.html, we now have a slo-mo video of a bicycle riding over a cattle guard, showing how the tire can compress almost all the way to the rim without damage.

Reader Howard Phillips has provided some updates on repair services.

Thanks to John Thurston, we have a PDF of how to overhaul the Sachs 3×7 hybrid-gearing hub.

It can run on propane, liquid or solid fuels!

Updates — Harriet and I have been updating articles and fixing dead links.

An idler is a freewheeling sprocket that can take a bicycle chain around a corner, or adjust chain slack.

Electric cars are too quiet.