Needs No Puller
One promising development is the crankset which needs no puller. Shimano introduced the first such crankset several years ago with its One-Key-Release system. More recently, Excel and Sugino began offering similar units. All work the same way.Instead of the customary 15-mm bolt, these cranksets use a bolt with a 6-mm Allen head. [Newer ones use 8 mm or, occasionally, 7 mm] This has two advantages: the necessary tool is small and practically weightless, and the Allen head can be exposed through a small hole in the dustcap.
The steel dustcap functions as the "nut" in a standard crank puller, and when you're removing the crank, the fixing bolt functions as the crank puller's "bolt." As you loosen the fixing bolt, the head of the bolt pushes against the inside of the dustcap, pulling the crank from the spindle.
This system is particularly well-suited for touring and for air travel when you need to remove either the pedals or the cranks to put your bicycle into a box. You can adapt other brands of cranks to this system by replacing the dustcaps and fixing bolts. Shimano, Excel, and Sugino all offer retrofit kits. They will work with all Type I cranks (that use a bolt to hold the crank to the spindle) with Campagnolo size (22-mm) dustcap threads.
Borrowed from SheldonBrown
http://www.sheldonbrown.com/tooltips/cotterless.html
