Bruce,

For 150mm cranks you have a few options. My custom cranks I refer to were 165 mm Truvativ Elita cranks which I had an engineer drill new holes in at 140 mm and cut off the excess. I then had a cycle shop tap the new threads in because the taps for the pedal threads are cycling specific. You could start with 175 mm cranks an have them shortened to 150mm. This isn't the cheapest option but you end up with the same quality of components. If you go this route you need to take care picking the cranks to modify. They need to be thick and wide without any scolloping or hollows. This rules out Shimano hollowtech cranks, Campagnolo or most of the FSA cranks I've seen. Truvativ Touro, Elita or Rouler seem to be suitable along with some Shimano Tiagra cranks.

Now at 150mm you have a few other options. You could get REALLY cheap cranks for childrens bikes in that size which could be a good tempory option to try it out and see what you think of them. Some racing cranks are also available in that length for juvenile racing bikes. I've seem some branded RPM along with Miche which makes them too. Another option that I'm currently using myself is BMX racing cranks which come in a complete range of sizes from 135 mm to 175 mm. I have some Sinz branded cranks with an ISIS spline that are primarily designed to take one chainring only but fortunately have a 110 BCD with 5 arms so they can take two rings and be set up as a compact double. Its not the neatest setup but it works a treat and their not that expensive.

See, http://factoryteam2racing.com/store3.asp and scroll down until you see the Sinz BMX crank armsets.

The other thing to note is that as you shorten the cranks you will want to push your seat rearwards and the plesant result of this is that the weight will come off your hands and you will be much more comfortable. See, http://sheldonbrown.com/frame-sizing.html

Oh yeah. I will never go back to longer cranks again!


Regards, Anthony