Rear hub wheels "normally" will have 135 spacing and some individuals (myself included) wouldn't "spread" an aluminum frame (I'm sure that lots of people would say I'm crazy --- probably true), but if you want a rear kit for both bikes you might email Paul at em3ev (very helpful and a respected vendor) or try ebikesca or ebikekit; however the last two won't come in under $1000 (IDT).