my gf rides a 50 on her tarck bike. she says the twitchiness helps in traffic. i also have a 50 on my grocery bike. the geo is different (soho s), but it's still great.
it will be twitchier, but not terrible. the bicycle's trail will still remain in tact, so the responsiveness of the ride will be unchanged; however, it will be more sensitive to what you do with your hands.