transmission woes

 

In my quest to make the bike more robust on the road, I have to address two issues: uneven tension in the chain between riders causing derailment, and also crooked chain lines. Because all chains are connected, if I change one component, there is a cascading effect through the entire system. The limiting factors of my modifications are that I am working with old components which are not easily found in today's bike shops. I have traveled many miles searching various bike shops and thrift stores for these parts, and now am hacking them up. The crank at the top is the first version of the replacement "transfer gear" which is currently wobbly. The crank at the lower left is the second version of the replacement, which should require less work than the first version. Having backup parts is always wise, and if you can make one faster than the other, all the better. The two hubs which are cut in half are to be turned down for their "donor threads" which is the only part I need to accept a thread on freewheel.

 

Here's a completed part. A new idea, which will hopefully solve the uneven chain tension problem. By placing a freewheel in between the stoker and final drive, this will allow both riders to coast freely and independently of each other, while disallowing any stopping or reverse forces to transfer back to our pedals. We already have the freewheel for the captain (the "transfer gear") and now I'm trying to create another one for the stoker. The completed part is shown, which is the center section of a square tapered crank, turned down to a cylinder, (donating it's square tapered hole) and we welded on a freewheel thread (donating it's threads) to create a freewheeling, chain driven input at the bottom bracket. Insanity? perhaps.

 

Here's Eva and David, who I thank for their cooperation and support in getting the Double Take on the road. Sponsorship can come in many forms, and their help is invaluable for our Diabetes ride! Thank you!