Trail-A-Bike to push trailer conversion

bodged bikes

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This Trail-A-Bike has been in my garage collecting dust since my daughter outgrew it years ago. I also had an extra Puch moped engine. Naturally, these two items had to be combined. Here is the result.

towped.jpg

eng_rt.jpg

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The original bottom bracket was cut out of the frame, and the engine mounted so that the front sprocket is located close to where the original pedal crank was.

The trailer wheel was built from a Puch moped hub laced into a 20” BMX bicycle rim and uses a 16” motorcycle tire. (Yes, 16” motorcycle tires do fit 20” bicycle rims)



Here are some details of the controls.

controls.jpg

Note that all three wheels have brakes. The two bike wheels use mechanical disc brakes and are operated by the right side brake lever. The two disc brakes are linked at the cable splitter. The trailer wheel has a drum brake and is operated by the left side lever. This lever has been modified to include a brakelight switch.

The extra, backwards mounted lever on the left side is for the starter clutch.


throttle_linkage_anno.jpg


The throttle was made from a mountain bike front shifter with the ratcheting mechanism removed. The modified shifter by itself does not pull enough cable to fully open the carburetor slide. To fix this, I fabricated this cable pull multiplier from a road-to-mountain bike brake adapter and some flat steel stock.



Here is a picture of an original Trail-A-Bike.
trailabike.jpg
 
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Very nice workmanship. Also interesting about the tire interchangeability. Question: does your trailer have a charging system? Like your centerstand.
 
Question: does your trailer have a charging system? Like your centerstand.

Yes it does. The original Puch engine comes with points and has low output 6v charging coils. I upgraded the ingition with a CDI system that includes a 50watt 12v coil. I am using a 12v regulator and a rectifier for the lights. The taillight is a cheap trailer marker light that I adapted to use 1157 type LED bulbs. The headlight is a small auto fog lamp with a 35 watt halogen bulb.

The centerstand is an integral part of the Puch motor and it happened to be located at just the right spot. With the trailer off the bike, it rests on the trailer wheel. On the bike, the trailer wheel is up and the bike is supported.
 
**** yeah, that is hot. If the controls are easy to add/remove, you could mountain bike with a pedal cycle one day and ride to work 20mi the next with the motor kit.

I like it. I think putting it in and out of the house would be difficult, but if you have a garage, that's the best idea.
 
Simpler way to go for the rest of us

I think your moped- modified trailer-bike is awesome, but here's a simpler solution for the rest of us with no welding supplies or skills.

Just put a BMP (friction or chain drive) kit on the trailer bike, intact, and use a LOOONG cable with a hinged-clamp brake lever for a throttle. You'll probably need a center stand for the pedal bike, but might be able to put it on the kid trailer instead.

This way, you can let a kid ride on the kid-trailer, AND use motor power

When you don't have a kid on the bike, but want to go to work or something, just sling back-packs or pannier set over the top tube of the kid bike, maybe even the handlebars could be used. Now you are ready to roll.

http://www.motoredbikes.com/ads/adp...=52&transferurl=http://www.bikemotorparts.com
 
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