Planetary gearing taken to excess

August 21st, 2009
bikes, transport
The schlumph mountain drive bottom bracket with planetary gears looks pretty cool. It is foot actuated and allows a reduction of 2.5. I was curious what sort of gears it would give my bike so I calculated:
front gear rear gear gear inches
1 1 18.6
1 2 25.5
1 3 34.6
2 1 44.6
2 2 61.1
2 3 83.1
No wasted gears, a nice shifting pattern with only one double shift, as low a gear as I could want for a really steep hill or a really heavy trailer. A total range of 501%, which is almost as good as a rolholff's 526%. The schlumpf is rated for use with coaster brakes, and my SRAM T3 is tough enough for the schlumpf. But how to justify $.5K for a new bottom bracket?

For reference, my current gearing is based on approximately 28 inch wheels (622mm rims, largeish tires), a 48 tooth front cog, a 22 tooth rear cog, and a SRAM T3 hub that offers 1st, 2nd, and 3rd at 73%, 100%, and 176%.

Comment via: facebook

Recent posts on blogs I like:

Abigail Shrier's Bad Therapy: Surveys

Surveys matter!

via Thing of Things April 12, 2024

Clarendon Postmortem

I posted a postmortem of a community I worked to help build, Clarendon, in Cambridge MA, over at Supernuclear.

via Home March 19, 2024

How web bloat impacts users with slow devices

In 2017, we looked at how web bloat affects users with slow connections. Even in the U.S., many users didn't have broadband speeds, making much of the web difficult to use. It's still the case that many users don't have broadband speeds, both …

via Posts on March 16, 2024

more     (via openring)