Many vintage race cars of the era carried along spare wheels during their race.  For that matter, they carried along a mechanic in the cockpit too!  Repairs along the roadside was very common back then.  It wasn’t until they realized how many mechanics were being killed in race accidents that they halted the practice of carrying mechanics in the race.

The rubber tire technology was not that good back then so tires deflating was very common.  Road conditions for races were often very crude as well which only contributed to the problem.  Bugatti lost more than one race due to flat tires. 

So in keeping true to the design, I decided to add a spare wheel as many of the Type 13’s did.  As my CycleKart was already heavy, adding another 14 pound wheel plus the mechanical support weighed heavily on my mind, pun intended.  So I elected to use a spoked bicycle wheel as it would be much lighter. 

Unbeknownst to me, motorcycle wheels and bicycle wheels are measured differently.  Motorcycle wheels are based on the diameter of the rim/wheel, whereas bikes go by the outer diameter of the tire.  Therefore matching the two with these differences turned out to be quite the education.  What I finally ended up with was a 24″ bike wheel with a 2.75″ wide tire.  The Shinko tires on the CT-90 wheels measured about 23.5″ OD so it was pretty darn close for the outside bike tire 24″ diameter.  Never-the-less, it’s not too hard to spot the difference between the bike and CT-90 wheels, but it was close enough for me, and the weight savings are worth the difference.

I built the mechanical support using 2″x1″ rectangular tubing and welded it directly onto the motor mount which was solidly welded to the frame.  It’s not going anywhere.  I was extremely proud of these welds, they looked very well done.  If only I was this good when I first started, oh well the next project will look much better.

I’m currently using a very small diameter bolt with a quick release mechanism to hold the wheel onto the support.  It’s a bit sketchy and it allows the wheel to rotate easily.  So I need to remedy this somehow.

I’m also using a 6″ diameter aluminum disc to act as a washer and to add my decal.