Do flies work the chest any differently than presses?

[Phineas]

I've noticed that I lift less on flies than on presses. Is this because flies work the chest differently or simply because the weights are farther from your center of gravity (thus requiring more leverage)?

I've noticed other regulars at my gym also lift less on flies. For instance, there's a firefighter who on presses lifts 75s and on flies around 55 (but also with a seemingly more controlled form).

Thanks a lot for any information anyone can give me.

 

[Skib]

I think it probably has to do with the center of gravity thing you mentioned but either way I've never heard of anyone being able to do flies with anywhere near the amount they can press... I don't personally bother with flies as they've never really done much for me anyways...

 

[Art]

Chest press with dumbbells and benchpress with barbell are both
compound exercises that work entire muscle groups.
Flyes are an isolating exercise that target a particular muscle (pecs in this case).

If you're going to do flyes, best do them after the presses so you don't
fatigue the pecs before the rest of the group is worked.

 

[PainandGain]

Flies put a lot of stress on your shoulder, and i have strained both rotators in the past, so i just stay away from them.
The most I've ever used on flies though was 35's.