Bike Stability Device

Designers: Brian Bigler, Anita Raheja, Margaret Widmyer, and Matt Davis

Supervising Professor: Larry Bohs


Our client has difficulty stabilizing herself on her bike due to cancer related treatments and surgeries.  The goal of this project is to create a device to provide stability during intervals of starting and stopping throughout a bike ride.  The Bike Stability Device includes a rotational system and a wheel support system.  The final prototype provides stability for the client and has the ability to rotate.  A future project will address rider actuation so the rider can move the wheels off the ground as desired.


The bike stability device will enable our client to realize her dream of riding her bike again.  Since she is stable once moving, having the ability to deploy and retract the wheels will give her the freedom and feel of cycling she desires.


The Bike Stability Device (Figure 1) consists of two systems: a rotational system and a wheel support system.  The rotational system includes two sealed ball bearings rotating on a ¾” diameter aluminum rod.  The aluminum rod mounts into a triangular plate that is welded to a commercial bike rack, so that the rod protrudes horizontally.  One bearing is pressed into a wheel support plate at the distal end of the rod, while the other fits into a stopper plate at the proximal end of the rod.  The support plate is oriented vertically downward, while the stopper plate is oriented vertically upward.  Both plates are made from ½” thick aluminum. The wheel support plate is linked to the stopper plate via two ¼” thick aluminum linkage plates mounted on the front and back edges, altogether forming a rectangle of ¼” aluminum for stiffness. Two shaft collars hold the bearings in place on the rod.  Two angular braces of ¼” aluminum between the support and stopper plates further strengthen the system.

An extension spring attaches from the top of the stopper plate to the bike rack, biasing the system towards the down position at rest.

A stopper plug, welded into the triangular plate, contacts the stopper plate to prevent rotation of the wheel support plate past vertical.

A wheel support system provides stability during leaning. The axle of each 12.5” diameter pneumatic wheel screws into the support plate as well as a T-shaped section, which reinforces the support plate and limits bending.  Each wheel attaches via ball bearings to its axle.  The support plate rotates about the previously described rotation system.  Cost of parts for the device was approximately $320.

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