The Excelsior Project, 6: Rear Wheel

The lathe work is complete, so the hub is mounted on the rotary table on the milling machine to drill the 40 spoke holes. The flange is in the way for this side, so the milling head was angled 6.5 degrees to compensate. I bought an extra long centre drill, and extended the drill used for the holes. Tricky little job.

The finished hub. At this point I've worked on the Excelsior project slightly more than a year. How those guys at West Cost Chopper can build an entire bike in 4 to 5 days is absolutely amazing. I take my hat off to them.

The finished rear wheel. They left the small sprocket on the right side, even though it wasn't used with the bicycle cranks. It's used as a dust cover for the bearing. Rubber is a Firestone Ribbed Racing Tire. Size is 28" x 2.25" and they have no steel bead. There's a rubber flange that hooks under the rim; the rim is rolled over to catch this rubber flange. That's all there is to hold on the tire. You can put the tire on by hand ... the rubber just keeps on stretching and stretching!  If you get a flat at speed, there's nothing to keep it on the rim. That's how dangerous they are. The concept of a steel wire in the tire's bead wasn't invented until the early 1920s.

Here is the eccentric. It clamps into the bottom bracket of the frame and allows adjustment of the chain from the engine sprocket to the jackshaft. The keyway keeps both sides of the eccentric in line with each other.

These are the jackshaft sprockets that mount on the eccentric bearings. The stock setup had a double-row ball bearing with the OD threaded (26 TPI reverse thread...) so the two sprockets threaded on. Very complicated and almost impossible to duplicate, so regular shielded bearings were used...


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