Tandem with rack mounted motor?


New Member
Apr 8, 2016
I don't know too much about bike engines, but I've started reading up on this forum recently.

My ultimate dream is to put an engine on my recently bought Columbia Tandem bike. I've attached some pictures so you can see the dimensions and the build. I've been looking around and here are some of the conclusions I've come to:
- Given the dimensions of my bike, I think it would be impossible for me to mount an engine within the frame, so I think I need a rear mounted/rack mounted engine.
- I think a 4 stroke makes sense for me, as people say it's smoother, a little quieter, and can be started from a standstill (all this appeals to me).
- I do not want a friction drive (Especially because I already have those metal fenders.
- I'm open to chain or belt, but...
- Based on the measurements, I think it would be impossible to install one of GEBE's drive rings, so that option's out.

I like the look of the Huasheng, and I've read good things about it, but it's a frame mount, as far as I can tell, so.. rather than buying a rear mount engine + kit, does anyone have any ideas about mounting a frame mounted engine with a rear mount bought separately?

I could be mixing terminology here, so excuse me, I'm new to the game.

I appreciate any advice, thanks!



Active Member
Jun 22, 2007
Welcome to the club, Jamesy!

Tandems have been done before.
For a 4-stroke rear engine rack-mounted kit, contact thatsdax.com.


Well-Known Member
Jun 24, 2016
I would consider trying a jackshaft honestly. I would say get a hold of KCvale and ask if you can get his 4 stroke long shaft for jackshafting and find a way to build it in?

Or go with a direct drive and a hub clamp to make things just barely fit? If you use a long enough chain and clever use of tensioners you can route the return chain around obstacles. You can also make a type of jackshaft that stays left side drive, it just brings the chain down to a smaller set of gears on a shaft that spin together, then you can change the direction of the chain without crazy use of tensioners.

Are you looking to invest more? I think if it were me and my wife on one of those I'd go and put electric in if possible, you've got enough room for batteries that's for sure. That looks like a fun ride for 2 people, especially so if motorized.


Well-Known Member
Sep 23, 2013
Poor Jamesey posted this thread over a year ago and didn't get any response :eek: but I guess everyone just ignores the rack mount forum section. :(

I think electric would be very cool too.
But the OP didn't say if this is for one or two people to ride.
I would love to build on a tandem frame, this could be really nice. I hope the op is still into MBs. :)