Can an ab roller propel a human like a motorcycle if fitted with an engine?

This project started from that question. While using an ab roller, some people feel as if they are becoming a motorcycle. I am one of them.

I used a Honda UMK435 brushcutter as the power source. Its engine is a 25cc, four-stroke GX25. Since this GX25 is equipped with a centrifugal clutch, I considered it suitable for this project. I mounted the engine switch and throttle from the brushcutter onto the handle of the ab roller.

In line with the concept of this project, I kept modifications to the ab roller to a minimum. The modifications I made are as follows:

• I drilled holes in the wheel to mount a sprocket (gear).
• I replaced the original handle (stainless steel pipe) with a longer handle.

The ab roller I used is the “SINTEX Training Abdominal Roller Exercise Wheel.” It consists of two wheels. I chose this model so that I could place the sprocket between the two wheels. This allowed me to keep as much distance as possible between my hands on the handle and the power transmission components for safety.

The engine’s rotation is transmitted to the wheel through four gears (including a sprocket) and two chains.

I added another ab roller. By placing my knees on its handle, I attempted to ride it like a two-wheeled motorcycle. However, it was unstable, so I increased the number of wheels from two to four. With more practice, I may be able to reduce the number of wheels in the future. I also had to replace its handle grips with flat-surfaced bicycle grips; otherwise, the grips would rotate under my knees.

It was powerful and difficult to control. I had to focus on gripping the handles and had no time to look ahead. Increasing the gear ratio might make speed control with the throttle easier.

After repeated riding, the chain became more prone to coming off. A chain tensioner will likely be necessary in the future.

Anyone who rides this must first be able to use an ab roller with proper form. They also need to strengthen their abdominal muscles; otherwise, there is a risk of injuring their lower back.

I named the Motorized Ab Roller the “Ab Rider.” This is the third Ab Rider. The first and second Ab Riders were powered by electric drills. I have never ridden a motorcycle, but I wanted to experience riding with the sound of an engine, so I chose to use a gasoline engine for this project. I worked on this project while imagining myself riding it under the open sky. I was able to enjoy the engine sound and my first pull start. I feel fortunate that I was able to make it happen. However, controlling it remains a challenge. It may be natural to solve that by strengthening my abdominal muscles.