Brian DeFord's Adventure
Building a Reverse Trike

Chapter 7

Rear Suspension

The rear suspension is based on a modification to sprint car racing axles and hubs. While researching for a good rear suspension design for reverse trikes I kept finding most where based on motorcycle rear swing arm designs that pretty much required the use of motorcycle components like axles, tires, and wheels. There where some fat tire applications that might have been adaptable to auto tires but the prices where out of this world for something I would likely modify anyway. While browsing my trusty Speedway catalogs one day I stumbled onto the idea of modifying open wheel race suspension designs.

I had a custom 2 inch splined axle machined by Diversified Racing of Lancaster, PA. They also machined a wheel hub to match that I specified to mate to a common 5 x 4-1/2 inch wheel hub. The hub allows be to mount practically any wheel designed with that mounting pattern. For the brake and sprocket mounting, I used standard off the shelf hubs designed for the 2 inch splined axle. The axle is mounted between to birdcage bearings again design for spring cars and those in turn mount to wishbones that I will pivot off the frame. The birdcages could be simpler but these were a good start and met my needs. I got most of the standard parts from Hyper Racing. Here are some pictures of the setup as I was test fitting them together.

Rear suspension
Rear suspension

I still have some open design items to consider before finalizing this setup. The rear suspension must be stiff from side to side but the wishbones aren't really designed to handle that without some sort of frame to suspension stiffener such as a panhard bar. Having only a single rear axle prevents that so I will likely be modifying the wishbones to give me the side to side stiffness required. Another option would be to eliminate the wishbones altogether and build a stiff swing arm designed to mount to the birdcages. I just haven't decided yet.