I am building the 29x3 (I might make a 29x4 in the future but don’t want to have to build the frame)
My friend Robert is building the unitank out of old snowmobile parts.
Awsome! The 3’’ 29’’ tyre would be sweet!
The unitank looks a go-er.I’m guessing it will probably need a bit of weight in the drive wheel to give adequate gyro effect.Can’t wait till it’s built and test ridden.I’m thinking it is obviously suited for your local snow and bog terrain but if successful it should work anywhere.
John
I reckon that tank will be very hard to steer with such a long footprint, but good luck to your friend building it - it’ll be a cool project.
The franken29er will work - you’ve already proved that with your other frankentyres. Presumably you’ll need to build a custome frame as well.
Rob
Yah he said he was going to try to give the track a bit of a rocker but you might have to hop-steer. I don’t think it will be too ridable but will be fun to try out anyway.
I am going to use a KH36 frame which I want for my next 36er anyway. If I were building a frame for this it would be able to take a 29x4 which I think would be the ultimate uni for the snowmobile trails.
Looking forward to seeing the uni tank in action.
When will we have a production model.
i’m looking forward to seeing the uni-tank, with some hard thinking and fiddly parts that could work quite well!
eric, you keep coming up with cool stuff! Way to go, man!
I rode a tank bike at a tour de fat event one time. It was geared so low that it was hard as heck to ride…at least for me. I’d love to try your friends uni when it’s done.
Cool bike! But before I had scrolled down to it, I was thinking your friend is building his track upside-down. If he builds it with the flat part on the bottom, it’s going to get caught in the first notch it comes to.
If you ask me, I’d try something more like what’s on that bike, with the track shaped like a semi-circle with the flat side on top. It should be heavy, but could be really interesting to ride and watch!
I really don’t know how Robert is planning on building the uni-tank other than it is going to be mostly old snowmobile parts with some bike parts mixed in. The sketch was just what popped into my mind when I thought “tracked unicycle”
Ktrak makes kits for bikes which includes a tread like this:
Not wide enough to provide much floatation though.
Since people slide down snowy hills on truck inner tubes maybe a rim designed to fit one of those bare inner tubes would be interesting in snow… provided one did not try to go up or down hill. 
Just a suggestion for anyone making a tracked unicycle, would it be possible to use the back end of a bike and a ktrak (see post above) to make a geared tracked unicycle. It looks like forward/backward balance would not be an issue given the length of the ktrak so freewheeling would not be a problem. However turning might be.
an idea for people with decent metalworking skills.
High flotation?
These are neat and all but how will you know if you’ve been successful? What terrain are you trying to traverse? Sandy beaches, deep snow, mushy swamp etc?
The idea with high flotation generally means bigger footprint and therefore more weight distribution.
Having only given this a few moments thought, I was wondering if you could do a tire that opens outward and spreads itself as it comes around to contact the ground. E.g. consider an inside-out bike tire, with the bead cut off and triangles cut into the sides so that it can open flat while contacting the ground. Attach the inside-out tire to a regular tire using rivets or something similar and mount it with a regular tube. Of course you would need a longer fork to allow the folded tire to pass through the frame of the unicycle.
…it sounds much simpler mechanically and should be pretty easy to prototype - especially if you have a surplus of used tires laying around.
-M
As it seems that turning may be a problem for unitank I’ve got a thought about having it with two tracks and to turn as tanks do with a different speed of tracks.
But I don’t have any bright idea how to control the tracks apart from having them connected separately to the cranks.
This is a common design for the Kinetic Sculpture Race, which includes over a mile of sand dunes. Instead of a second bike tire, they use something from a hardware store; I think it’s conduit for tubing or some such. (See the front tire).
saskatchewanian are you still building the 29er? Any updates?
Yah I was going to wait until everything was done before posting about it but it should be ready to ride for November.
I have already built a tire and going to build a second one. The first came out to 29x3.1 very similar width to my Gazz but rolls a bit faster and has a tad better float. It is too wide for a KH36 frame and too tall for a Triton triple mount frame.
the unitank on the other hand probably will never see the light of day, that is unless Robert gets really bored.
What about the nimbus boomerang uni? Take that hub and add an ATV tire. Just an idea.
I have thought about going stupid fat, Super wide hub from a Coker wheel, double rim, tractor inner-tube and fish net for tire and just some bent square steel for a frame.
But I am going with something that I actually want to ride and will be useful year around with the option to use regular tires.
The finished product should actually be lighter than my 26" MUni and plenty strong.
Speaking of tires…I recall another thread of yours about sewing two tires together to make a custom tire. It’s an old thread and I can’t seem to recover it…but I’m curious how that tire worked out.