Thorn short crankset

Short Cranks

Summary (2010)

After reading much of supposed benefits, especially for the knees, I wanted to try shorter cranks. After much searching the web I finally ordered the shortest set of Thorns cranks (140mm) from St John Street Cycles (highly recommended shop, and they delivery worldwide) and installed them with 40/28T first on my Pashley PDQ. I adjusted the boom length so that my legs where still only just bent at the furthest point of the pedal stroke.

After a short period of acclimatising I am hooked. Spinning is much easier (100rpm is easy compared with 90rpm before) and my knees feel much better, but of course YMMV, and it is also still early days for me. Speed at the moment seems the same as before, however since my spring cycling I have had a 4.5 week holiday without cycling and also fitted new tyres to the PDQ so the comparison may not be fair.

And I have bought another identical crankset for my Hase Kettwiesel.

UPDATE August 2013: I fitted them to my PDQ in August 2010, then my Zox in February 2012: see those pages for what I thought. And I kept them for my Vortex 2012 and am still happy with them.

UPDATE Decemeber 2015: still in permanent use on Kett and Vortex. Still loving them after 5 years !

UPDATE October 2016: still in permanent use on Kett but experimenting with 155 cranks with low Q factor on Vortex.

Pros and Cons

Benefits: higher cadence and less knee bend, more clearance for fairing, less risk of front wheel strike (SWB) or derailleur strike (FWD lowracer). With less knee bend OSS handlebars can be set lower. On a tadpole trike less risk of heal strike.

Negatives: cost: to buy new crankset or re-drilling existing cranks and then propagate to all bikes you own.

Tips

Links

Articles/forums threads (short cranks): Articles (crank length in general): Suppliers (esp. short cranks): Maybe you have found a good crank, but need an extra chainring (triplizer) (can also be used to make a single to a double): Suppliers (esp BMX 140mm (usually single chainring)): Shortening Services:
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