The Vorrezensenten have already said everything. I can only add that the bearings are really stable: On the inside (crank) is a needle bearing, which is protected with a shaft seal. On the outer side, a deep groove ball bearings with sheet metal disc. Before that still sits the threaded cap whose thread should fats for better sealing. Because certainly comes in no mess. Oil seal (12x19x3) and deep groove ball bearings (607 Z) are standardized, so available as spare parts (researched on the internet). The needle bearing, I do not want to specially develop to determine. Only weight and "coating" of the pedals could be optimized, in my view. The M4x8mm pins were too long and were replaced by 6mm; This protects my shoes and hands me the grip. Previously I had several Shimano pedals, their bearings and seals frequently caused me grief. A long time ago me with a Suntour pedal an axis is also broken. The one does not really ...
