Yes they do several and I have to say I was/am completely baffled at the differences between all the choices as it's not clear on their website at all!Oh Bafang have some different 250Watt rear-cst´s
If you give me your mailaddress I can send you the complete salesbrochure from Bafang.
I made photo from each page and there you can see also the measurement of each motors
A lot of different motor-drawings you can also find on my friend´s website in China:
http://www.woaczh.com/show_list.php?id=3
regards
frank