by Mad Mick » 29 Jul 2005 21:22
I'd be inclined to think there is not much relation to picking difficulty here.
Cheaper locks, which use spring-loaded locking bolts, will show resistance when the shackle is pushed in, partly due to the bolt-springs and also due to the shackle spring. The bolt-springs act upon the cam at the back of the plug, giving the increased amount of tension needed when picking, as noted by Chrispy. These locks can also sometimes be shimmed, if there is enough clearance between the shackle and the body.
When you get into ball-locking shackles, some have springs under the heel of the shackle and some don't. The ones with the springs will still give a bit of resistance (not on the plug though), but some locks such as Abloy (which have no spring) will give no resistance what-so-ever.
Another point to be considered with some ball-locking shackle padlocks, is that the balls are in direct contact with the cam on the rear of the plug, therefore it would be impossible to shim this type of lock. This shackle locking style requires less tension on the plug, when picking, than those with spring-loaded deadbolts. Again, Abloy uses this method, but since they use rotating discs, the likelyhood of picking Abloy's is very slim.
HTH.

If it ain't broke.....pull it down and see how it works anyway!