i have a 3 pc crank on my bike & bid on a set of n.o.s. rat trap style pedals for my bike that will replace my original 23 year old original pedals. the pedals i just bid on are the exact ones i have, or they look like the exact ones & are 1/2" like mine. the person selling the n.o.s. pedals says their for a 1 pc crank. why would that matter? what's the difference? the pedals look exactly like mine & are 1/2" which is what i have.