RyanCanfield said:
well what do i need to mesure so i know it works?? i see these numbers like 45/44/43 or sumthin. thanks
The numbers you're probably referring to are the chainring sizes. 44/34/22T rings are typical, although you may see some OE models with 42T big rings or 24T granny rings. Whatever they are, they'll work with your bike.
Crank arm length is typically 175mm, personal preference again. LX only comes in 175 or 170.
BB dimensions are 73mm (shell width) x 126mm (spindle length).
The shell is measured directly off your frame, as in the photo I've attached. Fishers are one of the few big manufacturers using the 73mm width in favor of the more popular 68mm width.
There are two spindle lengths that will work with the LX 572: 121mm and 126mm. These determine your chainline, or the distance of the middle chainring from the center of your frame. Because Fishers use fat bottom brackets, fat seat tubes and relatively short chainstays, the 126mm (50.0mm chainline) is the size I would choose. You might get away with using the 121mm for a narrower 47.5mm chainline, but be prepared with some bottom bracket spacers/shims just incase you get crank to bottom bracket interference, shifting problems, or chain interference problems with adjecent chainrings.