The SteamRoller Riding Contraption

Step 5 Gears and Chain

The gear sizes I liked were all available in 0.40 pitch chain. This is pretty beefy motorcycle style chain. I calculated a 3:1 ratio (three pedal revs = one wheel rev) for a practical top speed. This turned out to be perfect. I chose an 11 tooth gear for the the pedals and a 31 tooth gear for the wheel.

The chain comes in 10 foot lengths. I needed just a little over 5 feet per side, so I needed two lengths. If you want to save a few bucks you could change the design to use a few less inches of chain. It comes with one master link per piece. I would suggest buying a few more master links just in case you need them. I would also recommend getting a chain breaker.

I started out by placing the chassis on a couple of boxes to where the wheels would spin freely. This allowed everything to freewheel.

The first task is to mount the gear to the wheel. It is a bit tricky because the gear is about the same size as the wheel bearing blocks. I made an adapter plate out of 3/16" think aluminum. I used some 1-3/8" long standoffs to hold the plate away from the wheel. Be sure to allow access to the set screws on the bearing blocks after the gear is installed. I stood the gear off the plate with a nut and a washer to allow clearance for chain. Bolt this to the wheel centered on the bearing.

Install the wheel onto the wheel shaft. Slide it in until the gears are aligned. Wrap the chian around and measure the length needed. Break the chain then install it on the gears and put on the master link. Test everything and adjust as necessary.

Comments

[deemax]

How do you install the pedal gear, shaft collar and bearing into the wood? I've never used these before and am not sure how everything stays in place.

[bdring]

The bearings are not as thick as the wood. Drill a hole the outside diameter of the bearing with a spade or forstner bit only as deep as the thickness of the bearing, so you have a flat bottom hole. Then drill through about 1/4" diameter less than the outside diameter of the bearing to create a step about 1/8" all the way around. The bearings should press fit into the wood and sit on the step created. Use some tape to build up the diameter if it is not a press fit. The collars prevent the pedal shaft from sliding laterally in the bearings. Put a collar against the bearing on each side. You could actually use the gear as one collar if your steps are setup to install the bearings from the gear side.

[deemax]

Awesome, thanks again.