Steve's Recumbent Archives

'TreeBike' Rear Wheel Detail

Construction details for TreeBikes rear triangle.

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Well, here finally is a better (hopefully) description of how the rear 'suspension' of TreeBike was put together.  As you can see, I cut off and squashed the original rear triangle way down - hardly a triangle at all now. (The three vertical pieces in the picture are non-structural (rear rack))

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First, I squared off the front ends of the chainstays (kept as long as possible) and welded on a short length of 1x1 angle iron (C).

Next, I brazed a 1/4" x 1 1/4" cross-support (B) between the chainstays. This piece is mortised into the bottom of the rear-most bottom of the frame. Both this cross-brace and the top of the angle iron were drilled to accept two 1/4" stove bolts each (D).

A single bolt runs through the original 'brake stay' (A), the cross-tube where the old caliper brake mounted, and through the solid rear portion of the wood frame. This same bolt also secures the kickstand.

What can't be seen above is a small bracket mounted on the two bolts through (B) on which I mounted the current brake caliper.

That's about it. The weak point has to be the single bolt through (A), but so far there are no signs of weakness. Then again Sue only weighs about 100 lbs. and she doesn't stress it much. For a heavier rider I'd braze on another cross-brace similar to (B) to spread out the load a little.

If  I've confused you with all this please feel free to e-mail me and I'll try again. ss

As an aside...

Here is how I originally planned to build a suspension for this bike. Basically a very poor design (though the drawing looks good at first glance). Because there is no solid connection between the blades of the rear fork there would be a lot of uncontrolled twisting. I actually made this thing up, with steel reinforced cherry arms and a small cross-brace just aft of the rear of the bike frame. It was not as stable as one would like, probably due to do a kind of soft elastomer. Also, it probably weighed 5 pounds. A diversion and a lesson.

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