For low-load footblocks, you'll want
composite sheaves and friction cams. For
high load, alloy sheaves and spring cams.
The jammer holding load is no more than
300 kg / 660 lb. Be sure you don't load the
upper sheave beyond 60% of the Safe
Sheaves run on Torlon rollers with dual Delrin ball side thrust races. Alloy
sheaves, alloy bayonet cheeks for simply servicing. Safe working loads
are quoted for the whole assembly.