Adding Gears

When I am biking on a nice flat greenway I think to myself, why would I ever weigh down and complicate the bellcycle with additional gears? Then I am struggling up a hill and I think when are you going to add some gears to this thing?

 

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The first easy step was to extend the frame of the front fork on the right side to accommodate the cassette with the gears. The main load bearing side of the chain routing will remain the same. The return path has to be changed to add another pivot. This pivot will swing the pulley back and forth over the cassette allowing the user to select which gears to choose. I also had to increase the complexity of the tensioner because now there was a significant increase in the amount of slack that had to be taken up when the lowest gear is selected. 

 

As this is version 1 there is still lots of additional tweaking and improving todo. 

Comfort

I get a lot of comments on the street which are along the lines of 

Is that comfortable? or That looks uncomfortable. 

 

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But if you look at the images side by side and we can remove the bikes to make it more clear. 

The bellcycle posture seems better with back straight and hands by your side. The regular bike seems like the less comfortable one with head bent up and hands forward. 

In general I find both comfortable. 

Wooden Bike- A Fun Distraction

I have always wanted to build a wooden bike. But I am not really interested in the bamboo bikes or higher end models which use epoxy and composites to join the tubing/spars. I wanted something that was cheap. 

One great thing about NYC is there are a lot of people throwing things away. There is always a stack of wood in a dumpster nearby and routinely half mutilated bicycles are in the garbage also. 

 

Wood for the taking. I used the Oriented Strand Board (OSB) leaning up against the building and some of the 2x4's. 

Wood for the taking. I used the Oriented Strand Board (OSB) leaning up against the building and some of the 2x4's. 

I found this jewel in the trash a few months ago. Missing quite a few things but good enough.

I found this jewel in the trash a few months ago. Missing quite a few things but good enough.

The CAD files are on Github ( https://github.com/Bellspringsteen/Bellcycles ) and AutoDesk Fusion360 ( http://a360.co/2yxKDWi )

 

The design is similarish to the aluminum bellcycle bikes. It has the front frame which holds the same kind of front drive wheel. The center frame connects to front frame through a headset bearing and has the spring to remove pedal interference. The rear frame freely pivots behind the center frame. 

 

Processing the Trash Bike

 

From the trash bike we are going to need

  • Crankset
  • Chain
  • Jockey Wheels
  • Handlebar Stem
  • SeatPost
  • The side pull brake attachment points ( just hacksaw off)
  • Both wheels, tubes, tires etc. 
  • Headset
  • The top threaded tube from the fork. 

 

I printed out the shapes of the center frame pieces and laid them out on scrap pieces of wood. Cut them out. Made some poor joinery and glued the whole section together. 

 

I laid out the dimensions of the rear and front frame on the OSB. The OSB was .5 inch and I ended up doubling the width. I cut out and glued together the pieces. 

 

I assembled all the pieces. I used a lot of drywall screws in lieu of glue which I ran out of. 

 

  1. The wooden bearing caps kept on pulling out of the plywood. I will have to replace them with steel caps and potentially glue the screws in place. 
  2. The steel headset gradually deforms the wood and sinks in. This causes the connection to be loosened and the whole bike to sag. I.e. the center of the frame starts moving down relative to the front and rear. This causes the handlebar connection to rub on the top of the center frame which is not great for steering. 
  3. The cutouts for the chain are not quite large enough so the chain rubes on the plywood making noise and increasing pedal effort. 
  4. It looks great in person. 

Electrification

This is not a complete discussion of electrifying the bellcycle but mostly a product review of the AW Motor and Battery from Amazon. 

I purchased

  • 36V Lithium ion Battery - AW 36V 14AH Li-Polymer Battery Water Bottle Type w Holder Charger For 36V 500W 800W Electric Bicycle https://www.amazon.com/gp/product/B00XP538DI
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  • 20 inch bicycle hub motor AW 16.5" Electric Bicycle Front Wheel Frame Kit For 20" 36V 750W 1.95"-2.5" Tire E-Bike https://www.amazon.com/gp/product/B01C6QZ2US
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The battery kit includes a slightly noisy rear rack for mounting the battery. The rack was easy to install on the rear dropouts of the bellcycle. I just drilled and tapped two m5 holes into the dropouts and attached the upper mounts to one of the existing bolts on the rear pivot.

The motor kit includes all the wires you will need and they are already plugged in which is a nice time saver. The motor is heavy. I knew this but I forgot just how heavy. I mounted the motor controller under the rear battery rack. 

 

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  1. The cycle is fun to ride with the electric motor and that the motor has no problem with no pedaling hurtling you up to speed. 
  2. The battery has an impressive range, I have gone 20 miles and gotten home with the orange(but not red) light on and some still in reserve. Of course this is still with a good amount of pedaling. 
  3. There is now easily an additional 30 pounds in the rear. I feel it in the responsiveness. The cycle feels a "heavier" and less responsive. 
  4. Todo: The electric system is too big and heavy. Pedal Assist would be a better fit. The battery mounting takes up too much room.

Cargo Bike First Take

One of the benefits of the Bellcycles design is that the rear pivot allows the rear section of the cycle to be easily swapped out and as long as the height of the pivot remains the same, the cycle rides pretty much the same. 

 

So if you are mostly a bicycle commuter but occasionally you need to haul some heavy boxes you could just swap out the rear section of your bike with two bolts and bolt on a cargo back. In this case, I just used a 2x6 piece of wood with an old bmx fork and two small wheels. 

 

The worlds longest bicycle is 117ft says the Guinness Book of Records. Thats not really that long. I could build a light 120 foot beam ( wood? Foam/Fiberglass? Carbon Fiber Tube?) and bolt it on the end.

V1.15 Rear Pivot

Where should the rear pivot on the cycle be? From v0.5B when I stuck a office chair caster wheel on the cycle the pivot was very close to the rear wheel. But in later version to simplify the design I moved the pivot towards the front.

 

The results? Its more maneuverable. You can perform tight tight turns. Its more fun!! But its also a little more challenging at low speeds. I think for the first version to release, I will go with the pivot towards the front but possibly with the possibility of the back pivot.