Introduction: Adaptive Bike
Our church operates a bicycle ministry which repairs old donated or discarded bicycles for distribution to financially deserving children and to homeless individuals in need of transportation. This past year we expanded the program in a new direction and began building adaptive bikes and trikes for children who face physical barriers which inhibit their ability to balance, operate or pedal a typical bike. We established a working relationship with our County Department of Education which identifies children in need of such bikes and they also provide a professional assessment of the exact needs of each child so that an appropriate bike or trike can be built to fit the child’s needs. We have also gained the support of local law enforcement which provides us with their “lost and stolen” bicycles which we use for parts. A few of us from church do the designing, cutting, welding, and painting for each bike or trike. The finished bikes/trikes are provided free of charge. Hopefully this Instructable will encourage other “maker” folks to start similar programs in their own communities.
Our first adaptive bike was for a young woman with balance, stability and leg strength issues. In response we built this 16" bike with customized foot supports for the pedals and very heavy duty but low resistance training wheels.
Step 1: Foot Supports
The adaptive "foot supports" enlarge the size of the pedals and allow the users foot to be stabilized on the pedal with a heal stop and an adjustable strap to keep the foot from sliding off either side of the pedal. This adaptation can be utilized for any child having difficulty while first learning to ride.
The base of the foot support is made from two identical pieces of wood cut from 3/4" cedar fencing material available at any Lowes or Home Depot. The shape is created using the pattern of a child’s shoe about 1 or 2 sizes larger that the child riding the bike. Each pedal requires two of these pieces, one on top of the pedal and one on the bottom. The two pieces are sandwiched onto the pedal with carriage bolts. A strip of lightweight rubber material (we used automotive weather stripping available from J.C. Whitney and other automotive outlets) is wrapped around the heal of the foot support. The rubber strips are held in place with contact cement and a series of small nails.
Step 2: Foot Straps
The foot strap is made using nylon material commonly used for tie downs and found at hardware stores or Home Depot. Cut the outside strap about 5-6" long and use a match or butane lighter to melt the cut edge to keep it from fraying. Cut the inside strap about 7-9" inches long. You will want the longer strap originating on the inside of the pedal to overlap the shorter strap originating on the outside of the pedal. This makes for easier attachment and removal of the straps. The strap lengths are best determined by trying them out with the child’s foot (with shoes on) in place.
To hold the straps tight, cut a length of velcro tape about 5" long. The tape should include both the “hook” side and the “mesh” side. Use 3/4" wide tape or wider. Sew the “hook” side of the velcro to the top of the outer strap and the “mesh” side of the velcro to the bottom of the inner strap. If you are using self sticking velcro tape, sew them anyhow. The straps will get a LOT of abuse and the velcro needs to be firmly sewn on. Attach the straps to the wood supports using contact cement and pan head screws.
Step 3: Counterweights
As soon as you bolt the foot supports to the pedals you will notice an immediate problem. Because they are now “top heavy”, the pedals will almost always flip over and end up with the straps facing down rather than being on top where the child can easily insert their foot. To remedy this problem we used large washers as counterweights. The washers are screwed to the underside front and rear of the support. After a bit of experimentation we discovered we only need two washers in each position rather than the five shown in the photo. But each pedal support will be balanced a bit differently so you’ll need to test and adjust accordingly.
Step 4: Training Wheels
Manufactured training wheels are readily available for bikes and many smaller bikes come already equipped with training wheels. Unfortunately, most of these wheels have lightweight flimsy supports and the wheels themselves have either poor bearings or no bearings at all. As a result they do not roll well and can actually interfere with pedaling. We therefore build our own training wheels. The supports are made of 1" wide flat stock welded in a triangular shape to give them plenty of strength. The axles are 3/8" bolts with the heads cut off. The bolts are welded to the underside of the wheel supports. The wheels themselves are salvaged off of abandoned/discarded shopping carts. Sometimes these wheels have poor “tires” and the rubber will have visible flat spots (these are what cause wobbly wheel syndrome at the grocery store). Do not use flatted tires. If the tires are okay, the wheels themselves have very decent bearings in them and will roll far better and longer than cheap training wheels. Also, obtain these wheels only off discarded, broken, unmarked (store identified), abandoned carts or carts sent to your local crusher site.