dumbell shape and weight

[StoneColdGold]

A more compacted weight should feel lighter and something spread out should feel heavy and harder to balance.

Absolutely. In physics, its called "moment of inertia." Very simply put, the more spread out a body is from its center of mass (which would be the middle of the barbell in this case), the more inertia it has. And of course, seeing as how the weight starts from a dead stop and you must repeatedly change the direction of the body, this means more inertia working against you.

 

[trial0r]

ive noticed a difference from dumbell to dumbell in different gyms. sometimes the grip just feels weird and throws off the whole set. also, some gyms dont count the bar of the dumbell, only the plates on it. thats like 2 pounds or so plus those tiny collars on the end...i guess it could make a difference.