As mentioned in the Introduction, I purchased the plans for this pedal car project from Stevenson Projects a few years ago. These plans are at least 20 or 25 years old, and are not professional CAD drawings, but the good news is that they don’t need to be to be effective. They are detailed and clear where necessary. They claim that there are no special skills like welding necessary to build the car, and that may be true, but I deviated enough from the plans to get stumped in a few places.

As is my habit with things like this, I read the plans over completely at least three or four times after receiving them and before making any supply purchases. I knew from the start that I would be changing them in a couple of key areas, and wanted to be sure I understood the original intent of every step.

The supply list includes a number of items that I know now were constructed of much better raw materials when the plans were written than they are now, such as angle brackets and galvanized pipe fittings. But with some creative thinking and plenty of browsing at local hardware stores, I think I’ve been able to do okay with substitutes and a bit of trial and error.

The fundamental design of the car is based on the old, common pedal car drive mechanism: drive rods and a crank axle. The pedals move back and forth to crank the drive axle instead of in an orbit as standard bicycle pedals move. These pedals are tied via drive rods to a specially-bent rear crank axle that drives one rear wheel, with the second rear wheel spinning freely (without a differential, only one rear wheel can be the drive wheel or things will lock up when you attempt to turn). The frame is made of 1″ fir and 1/2″ plywood, and the body and fenders are almost exclusively 1/2″ and 1/4″ plywood.

Each front wheel is mounted on an ingenious assembly of cast iron pipe fittings that lets them rotate easily on the threads. Short arms extend from each assembly to provide an anchor point for the tie-rod.

The primary deviation I made from the plans was to choose real spoked bicycle wheels instead of the solid wood wheels detailed in the plans. Unfortunately, this seemingly-simple change was tied to the two most complex pieces of the project: the steering and the drive mechanism. By choosing wire-spoked bicycle wheels, I made the general wheel mounting instructions from the plans completely useless, and forfeited any obvious method for connecting the drive axle to a rear wheel. This is what derailed the project after my intial progress, and only after talking with some very knowledgeable folks have I been able to get back on track.

I started this project years ago, and it has sat, unfinished, in the garage. As a result, the freshly-cut look of the wood has been dulled with dust and piles of typical garage junk. But I have disassembled as much as I could, taken pictures to show progress, and reassembled things. The following subset of pictures shows some of the frame and rear wheel mounting progress. The full set with descriptions on each image is available on Flickr: MG-TC Pedal Car.

My next post in the series will show the front wheel assembly and mounting, and then on to the body and fenders.

Tags: Pedal car