Ugly Trike Steering Linkage

steering_linkage

This is the completed steering linkage for Ugly Trike. I constructed both the Akerman correction tie rod and the steering linkage drag arm from a steel shower shelving unit rod  and 1/4″ rod end bearings from vxb.com. The rod end bearings are the “correct” solution, but the ones I purchased from vxb.com were annoying because they used fine threads (1/4-28tpi) instead of the more standard 1/4-20tpi, so I had to special order some 28tpi bolts and weld nuts from McMaster-Carr. Also, finding left hand thread nuts and bolts in 1/4-28tpi was very difficult, so I just ordered extra left hand female rod end bearings and welded them into the steel rods to act as my left handed nuts. (Expensive nuts, but cheaper than shipping them from elsewhere…)

 

weld_nut2weld_nut_finished

I used the already existing handlebar brackets on the stems as the pivot points, and drilled a 1/4″ hole into them to mount the rod end bearings. One nice feature of using the stem is that the angle of the pivot point to the wheel can by adjusted simply by twisting the stem appropriately when you install it.

I had to add two more pivot points for the drag arm that connected the right hand stem to the center handlebar stem to complete the steering linkage. For that I cut the ends off of an extra front fork, ground the end down to a fish-mouth, and welded it to the stem. I welded two nuts to the end to attach to the rod end bearings.

fishmouth


dry_fit

knuckle_weld_closeup

The one boneheaded thing I did when first setting up the drag arm was to build a reverse steering trick bike….It is VERY difficult to ride a bike where the handlebars turn the wheels in reverse of what you are used to….messes up your balance something fierce…luckily, this is why I use scrap wood to prototype my linkages before welding them, so I caught my mistake relatively quickly….. it’s too bad, as the reverse steering linkage was a lot more compact…

reverse_linkage

Two links that I found very useful for learning about bike steering linkages were:

http://www.eland.org.uk/steering.html
and
http://www.ihpva.org/Projects/PracticalInnovations/weld.html#Trike%20Steering%20Geometry

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