Bob's bike pusher trailer project.

[rbelisle1]

So after reading about Ross and his bike pusher, I decied to try my hand at it. The design criteria was to build it cheap, build it strong, build it so it could hold our insulated cooler bag so we could not use the car to run small trips to the store near by (less then 1 mile away)

The motor(my1016 250w, 24v), controller (unknown maker), tires (one knobby, one not) and rims came off of a Craigslist $30 scooter. The Steel frame is all 1/8 inch by 1 inch L or ¾ths inch .065 square steel. I brazed it up, rather then weld, as the braze is easier to take apart and reuse the steel if need be. About 20 bucks worth of steel at the scrap yard.

A little bit of math, via one or more of the online gear and tire calculators, found that I should get about 15 mph out of it. The motor has an 11 tooth, the wheel has a 64 tooth and the wheel is 12 inches diameter. Top speed, in reality is 17.1 mph. with me a 185 pound rider.

The batteries are 2 u1 size 12v 33ah monsters that I paid about 100 bucks for.

Bottom line is that it works as designed, but driving it leaves a lot to be desired. The power is good, even from a dead stop, without pedling, top end is good, handling and brakes are good, its just so dang wide and it does hop on every little bump in the road.

So far Ive got about 15 miles in test runs and no issues to report….

Here are the pics….
http://members.cox.net/rbelisle1/with%20bag.JPG

http://members.cox.net/rbelisle1/withoutbag.JPG

http://members.cox.net/rbelisle1/deckoff.JPG

http://members.cox.net/rbelisle1/hitch.JPG

http://members.cox.net/rbelisle1/sprocket.JPG

I still need to paint it ,, maybe this weekend….

Bob in phx.

 

[D-Man]

Nice job. How long did the project take to build?

 

[rbelisle1]

Got the scooter on Friday, the steel on Saturday morning, ready to ride Sunday, finishing touches (deck and fenders) after work Monday and Tuesday. Lots of grinding / cutting etc. I drew up the plans on Saturday morning, during a 4 hour piano recital. Good thing I like my daughter, because that recital was painful!!!!!

 

[paultrafalgar]

I wonder if you could put one of those Constant Velocity Joint connectors that are used in front wheel drive systems on cars in your trailer connector. Maybe that would take up the jolt on bumps? They are basically a rubber block with a bolt coming out of each side. Or am I thinking of a exhaust/muffler pipe suspension point?

 

[gogo]

Thanks for posting your experience. I'm making note of your comment about the trailer hopping. Do you think a suspension on the trailer would be worth the effort and expense?

 

[rbelisle1]

I did discuss suspension with my younger brother (a mechanical genius!!!, really!!) and we decided that a suspension system would weigh a lot and wouldn’t get rid of the wheel hop. He followed me in his truck to get an eyeball on what was going on and decided that a combination of rough roads and motor power were the issue. The trailer hits a bump, the drive tire lifts a little (not off the ground) and the motor causes the tire to loose traction for a split second. This creates a little bit of a jolt, as the tire regains traction with the full weight of the trailer back down on it. Note that the drive tire is a Knobby, were as the no driven tire is a normal street tire. I will be changing the tires around and we will see if that gets rid of the issue. We felt that the bounce was just inherent in the idea of a trailer.

Took about a 10 mile ride today and the batteries never even felt close to puttering out. The biggest issue is making corners that would be easy on a "normal" bike. Like say an intersection where you have to make a very sharp 90 degree corner. It not easy with a trailer. There was no interference from the trailer, but it does stick out back there and on the sides... Not a show stopper, but not real easy either.