Originally Posted by
fuzz2050
Not always. Sealed just means that there is a seal of some kind over the bearings, not necessarily that they are cartridge bearings. Sometimes marketers use 'sealed' to indicate cartridge, but other times it just means 'having a seal against the environment.' All shimano hubs are 'sealed' and they all use loose balls.
That small distinction aside, I doubt you'll know the difference riding it, and chances are you'll never actually need to do a pedal overhaul.
the vast majority of cartridge bearings aren't really "sealed". they're sealed against airflow, and big debris getting into them. That's great if they're on a fan spindle or an electric motor. On a bike, it's not very useful, since they're not sealed against water ingress, which is what typically kills bearings. You can get beter sealed cartridge bearings. they're more expensive, and are harder to find, and will have more drag, from the added seal. (you'll not notice, unless you're in contention to win the Tour, in which case why do you car how long your bearings last?) The other thing that some "sealed" pedals do is ditch one of the bearings and replace it with a bushing. It saves them money, and produces an inferior pedal. (at least in terms of durability. Might save a couple grams)