If I put my batteries in a small trailer thus removing their weight from the bike could I beat the letter of the law though maybe not the spirit of the law? Maybe put the drive wheel on the trailer as well ( I have a brand new 16" goldenmotor wheel) making conversion from electric assist to straight pedal bike a very simple affair! If I build a small one wheel trailer, connected to the bike with a universal joint, it will lean into the turn with the bike thus minimizing fishtailing. It would be easy to build a inertia brake like u-haul once had on their trailers to help take care of the stopping. you could put as many batteries back there as you like! it could be built quite low to minimize the influence it had on the bike. What do you think?
Ed Service

Electric Bikes?

I don't know anything about a weight restriction; that must be a local law. Putting the drive, at least, on a trailer would be a Bad Thing(tm) - can you spell "jackknife?" Also, if you used a U-joint with a single-wheeled trailer, it would simply fall over. These questions might get more useful answers on an e-bike list.

I subscribe to both this forum and electric bikes and mistakenly posted the question here. however, there are some commercialy available pusher trailers. Also I've seen some homebuilts on the internet. Mounting with a ujoint the way I want to do it would specificaly prevent it from "flopping over". Jackknifing might be a problem but would batteries mounted low on a trailer be any more dangerous than the same weight higher on a bike?
Ed Service

I subscribe to both this forum and electric bikes and mistakenly posted the question here. however, there are some commercialy available pusher trailers. Also I've seen some homebuilts on the internet. Mounting with a ujoint the way I want to do it would specificaly prevent it from "flopping over". Jackknifing might be a problem but would batteries mounted low on a trailer be any more dangerous than the same weight higher on a bike?
Ed Service

Jack knifing does not have anything to do with the height of the load - that is roll-over. Jack knifing is the inertia on the pivot point (either from the front or back) or loss of traction of one element or the other causing a loss of control at the pivot.

That said, the lower the center of gravity, the less likely you will be of roll over.

Any yeah, I drive an 18-wheeler. :D

I don't know anything about a weight restriction; that must be a local law. Putting the drive, at least, on a trailer would be a Bad Thing(tm) - can you spell "jackknife?" Also, if you used a U-joint with a single-wheeled trailer, it would simply fall over. These questions might get more useful answers on an e-bike list.

I Think this is my first post in the bent section of Bike Forums. Been lurking a while.
I have a Logo trike and built a two wheel push trailer for it. The trailer has electric drive 300w to the left rear wheel and batteries 2 12v x 18 ah in the trailer. We are limited here in power to 200w so I'm a bit over but suspect the cheapo motor is less anyway.

The gloom and doom brought up all the theories about jack knifing etc etc but strange to say that wasn't the case and the whole setup is well behaved. This may not be the case of course with more power.

My little rig gets me along at 30kmh on level ground but is mainly for the hills when the trailer is loaded. The beauty of it is that the trike is not modified and I only go electric when I have a need.
Can post pics if interested.

Regards,
John Lewis

It is easy to imagine all kinds of horrible things that could happen! I'm glad to hear from someone who has tried it. A single wheel trailer should be even more wellbehaved with more centered push. I have three bikes I like to ride, having one pusher that would work on them all would be great!
Ed Service

Are these push trailers like if you had a couple of strong kids and pulled them in a trailer that was propelled by them?

This is what I had in mind!
http://www.e-ride.ca/Electric_Bikes/Electric_conversion_trailer.htm
Ed

I've been an engineer for thirty six years. I have designed a push trailer I intend to build and the single wheel is how I intend to proceed. You don't want a universal joint though. Single wheel trailers are always attached to both sides of the rear axle. There can be two rotating elements in the linkage. One can be horizontal (simple way to do this is with axle extensions and ball bushings on the trailer arms) to allow the bike to pitch up and down in relation to the trailer; as in riding up over a curb. The second one can be vertical, very close behind the rear wheel of the bike to allow the bike to yaw to the left and right; as in making a turn. The closer the trailer wheel can be to the bike wheel the better it will all handle. The movement you can't allow to be indepentent is roll. When you lean the bike the trailer must lean with it. Having said all this, there is one more point you made that is exactly correct; the lower the load (batteries) the better it will handle also.

A second advantage to a trailer is it gives you a place to mount a solar panel for charging the batteries while you are at work if you plan to use this as a commuter bike.:thumb:
Good luck with your project.

My idea of a u-joint is to give exactly that 2-axis movement in a small cross section. u joint is probably heavy for the job but it is very simple to incorporate. It also gives a very convenient disconnect feature if I use a snap coupler yoke like on a small tractor.

Dunno anything about electric pusher trailers, but to an old simple mind like me isn't it easier to pull a chain than push it? As Crank 57 says, attatching it to the back axle would make it handle much better. An Intriquing project...

You don't want a universal joint though. Single wheel trailers are always attached to both sides of the rear axle.


True of sigle wheel cargo trailers. Trail-a-bikes on the other hand all attach to the seatpost via what amounts to a U-joint, which synchronises the roll of the tug and trailer, while allowing differences in pitch and yaw...what is a trail-a-bike if not a trailer with a noisy, expensive, and underperforming engine?

Most single wheel trailers that attach at the axle have the problem of placing the yaw pivot behind the axle. This can result in dynamic instability (sway) . Placing the yaw pivot at, or ahead, of the rear axle is much more conducive to stability...the reason trailers beyond a certain size need fith-wheel or gooseneck connections to the tug.