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This talk about a Detroit Locker makes me think that I need to come up with some sort of ratcheting device for the diff. That way I can probably still run 1 rear brake too.

If I run a double freewheel, then Ill need 2 rear brakes.
 
Ratcheting like a Detroit EZ locker. The axle shafts would rachet against each other.

Something like this:
lockright.jpg


Or I could just do a front brake only, and do a double freewheel.
 
This talk about a Detroit Locker makes me think that I need to come up with some sort of ratcheting device for the diff. That way I can probably still run 1 rear brake too.

If I run a double freewheel, then Ill need 2 rear brakes.
I am not sure how you would go about making the ratcheting system using bike parts... One rear brake and one front brake would be more than enough to pull the bike up though, two rear discs would be really cool... ;)

Luke.
 
I had the idea of taking 2 pieces of heavy wall tubing, with a 3/4" ID. I would cut "teeth" into one end of each. These would mate together. On one side of the drive axle the pipe would be bolted solid. On the other side the pipe would be slotted and have just enough slip to allow the teeth to slip across each other. I would use an automotive valve spring to press the 2 pipes together. Theoretically when peddling and braking the spring would be strong enough to lock the 2 axle halves together. But the fat tires would have enough traction to overcome the spring and allow the teeth to slip across each other when turning. Basically like a Detroit EZ Locker.
 
Thats true, but I wonder how lone they would last? I bet this bike won't get 100 miles total each year.
 
I got the hubs on. One is perfect, the other has a tiny bit of play, probably not even enough to put a shim in. I ended up cutting the axle into 2. It steers much much easier now, but 1 tire fire won't work in the sand. I'll figure that out at some point. Next is getting the derailer setup and brakes working.
 
Ya, that would be cool, but too much $$$. I'll get it sorted out once the rest of the project is done.
 
I had the first official test ride tonight. I have working rear gears and a working rear disc brake.

I didn't want to spend too much money on this build, and I wanted to use as many parts on hand, so I ended up using a friction shifter going to a cheapie rear derailed. It has a 7 speed freewheel, but the rear frame assembly slightly blocks the high gear, so its a 6 speed. The rear brake is a Tecktro Hydraulic that I had laying around and the rotor is 203mm. It stops well enough to slide the fat tire, and this bike is just for cruising, so I doubt I'll put a front brake on it.

The next step is to build the rear bench for the kids, figure out a locking diff, and give it a little paint. I may end up putting some sort of head and tail light on it too.

Here are some pics:

8d55406a67812d6b44da27066fdc0601_zps31c98910.jpg


5ec9c343e013616c290a3d6c7f19b18f_zpsdd486c31.jpg


2227fd4e2236b4ff64d343438225303f_zpsed0df5ec.jpg


7dca6346f5a64a5d513363d000e44dd4_zps26839632.jpg


8341f7818befbec095507784fdd53cf1_zps60d1ebca.jpg


920ec3262c8ca1825581ddf93d24d63d_zpsc017f2c3.jpg
 
as far as brakes go, with motorcycles its 70%front 30% rear, not shure about bicycles, but if its not too fast i would think a front disc would do fine, if you could get drum brakes on the rear also, well that would just be sweet
 
70/30 braking is the same on bicycles too, probably car too I would think. At this point I'm fine with the rear only brake. It will only get better once I figure out a locking rear diff!
 

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