Unicycle Master's Degree in Engineering Thesis

What Erik said.

A CVT-geared hub

Please design a seat that is comfortable, if that isn’t possible, design a seat that doesn’t hurt.

That one gets my vote, too. I actually have an idea how that could be done!

A suspension that absorbs impact at the wheel, not the seat. Plus everything above!

What about a comparison of these type of technologies (Lauf, LoopWheels, SoftWheel) alongside regular wheels (3" and 4" tires)? I’ve been trying to do this informally with peg unicycles but it’d be nice to see a scientific approach and what the methodology would be. You might incorporate a self-balancing algorithm in testing since it’s difficult to build pedal wheels with these technologies.

Or abandon all of this, come to PowerKiteForum and help me design a better buggy, preferably one with a rollover bar given my recent trifecta of those.

A colleague sent me this the other day…

Using Evolutionary Multiobjective Optimization Algorithms to Evolve Lacing Patterns for Bicycle Wheels

Quite interesting.


When muni riding, if you hit a rock you didn’t see it can stop your wheel with a high chance of UPD type 2 (what I call the one where parts of your body other than the soles of your feet absorb some of the impact of your descent from the unicycle to the earth), but at least a UPD type 1 (where you run out and feel like a pro).
My subjective impression is that when most of your weight is on the seat you are riding a vehicle without suspension so the wheel can’t rise up over the rock. That makes a UPD more likely.
If you see the rock coming, of course you hop at least a bit and that is like “active suspension” as I understand it. But I think if you only lift off the seat without hopping at all, that allows the wheel to rise over a rock better, even though your weight is on it through the pedals. Your legs must flex to work like suspension if that is what happens. Lifting off the seat allows you to ride over bumpy ground which is evidence for the above. Of course, when you know the rock is coming, if you just unweight the seat, you also push harder to rush the tyre over the rock.
My proposed question is this: Does some spring in the seat post allow you to ride over a rock better without lifting out of the seat? Further: if so, does it increase your chances of making it over a rock with no preparation because you didn’t see it?

Once again, thanks everyone for the ideas. I have quite a few areas to look into. Probably the harder part will be deciding what I want to do and how to do it…

If you’ve got more ideas, don’t hesitate to add to the others.

I’ve always wondered why we use ball bearings instead of taper roller bearings.

Based on my experience with suspension posts (and air seats), maybe a little, and maybe.

I’ve used various suspension posts over the years, but there is a limit to what a suspended post will do for you. It absorbs shocks to your butt/crotch, but doesn’t help on what’s happening to the wheel and your feet. I remember one time riding on the Downieville trail, where I hit a rock I didn’t see while the pedals were near vertical. The wheel came up, the frame came up, the suspension went down (all at once), and then, because I hadn’t prepared my body for this bump, the post bounced back up, lifting me right off the seat and into a weird UPD.

So you still have to pay attention. Also you must consider what’s happening to your seat height. Adjust the height so that it’s optimum with your weight on the seat, and it will be a little higher when you’re riding uphill, through technical stuff, etc. Got to allow for those variations. If you have it set too high, you get bounced off the seat like above. Too low, and it’s just hard on your knees (like riding long distances on a Trials or Street uni).

In the end, I think the best use of suspension on unicycles might be a short-travel design for Road riding. In that style of riding your weight is on the seat the vast majority of the time, and if it works right, it will take the edge off of the irregularities in your road surface.

That’s an easy one: taper roller bearings need axial preload. The legs of the unicycle frame are not stiff enougt so be abele to build enough counterforce to this axial preload. It won’t be possible to adjust a defined preload and preload will change all the time as the frame flexes.
In a bike hub it’s easy: the inner rings sit on the axle and the outer rings sit in the hub. So its easy to apply a defined axial preload with nuts on the axle pressing against the inner rings.