A piston engine is oversquare if its cylinders have a greater bore (width, diameter) than stroke (length of piston travel). This is generally considered to be a positive trait, since a longer stroke means greater friction and a weaker crankshaft. An oversquare engine is more reliable, wears less, and can be run at a higher speed. Power does not suffer, but low-speed torque does to some degree, since torque is relative to crank throw (distance from the crank center to the crankpin)—the leverage, essentially.
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