Monday, December 27, 2010

Cargotrike Plans = Cargo Trike Plans

All of the above measurements are in centimeters (cm)

The approximate inch (") measurements are: 
88 cm = 34-5/8"  (35)
127 cm = 50"
208 cm = 74"
50 cm = 19-11/19"  (20)
36 cm = 14-3/16"  (14)
62 cm = 24-7/16"  (25)
85 cm = 33-1/2"  (34)

The numbers to the right i.e. (35), are what I'd probably round the inch measurements off to.   That's what happens when you don't have a nice metric tape measure ...
Here's another view of a cargo-trike frame without the box
Of course this is a modern one with 20mm axles ...
it takes something heavy-duty like that to only support the axle on one end. 

To build one of these, the simplest would be to use a single-speed bike (donor, trash, or thriftstore) with a Bendix brake on the rear.  Cut off everything in front of the Bottom Bracket (BB) -- that's the part where the crank connecting the pedals goes through the frame.  And everything in front of the seat tube.  That leaves you with a rear triangle, seat tube, and bottom bracket all in one piece.  The cargo box and new main tube (which you will make) will connect to the front of the BB.

I decided to start on a cargo trike.  I needed something for the box out front to pivot on ... I looked at headset bearings and decided they were just too small.  So I cut a large bottom bracket off a bicycle that has a single-piece steel crank.  I cut most of the crank off on the side with the sprocket gear ... leaving just enough to hold the gear in place.  I figure to tack a thin metal plate to the single gear.  And that will then bolt to the frame of the box.  (see 6/17/11) Once I'm done welding the plate to the gear, I'll cut off the left-side crank leaving just a nub.  That should give me a good sized bearing.  And it will be serviceable ... to re-grease the bearings and change bearings & cups.

This unit will be the pivot base of the cargo box.
The box frame will bolt to the gear unit.

The steel tubing will be welded to it ...
the other end of the tubing will be welded to the BB on the rear of the bicycle.

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