System for eliminating deadspot

Saw this today, its supposed to eliminate the deadspot when pedalling a bike.

Wonder what this would be like on a unicycle?

What begins as a bad idea on the bicycle will turn into a worse one on the unicycle, as I’m sure the cranks are not designed to deal with pressure applied in the backwards direction.

Complete nonsense. Another example of I don’t practise my archery so I need a better bow.

I suppose it may help the type of cyclist who just stomps down on the top pedal, but that’s not how you should be pedalling. I wouldn’t fancy trying to spin that setup at any sort of speed. I’m very sceptical, but if anybody wants to buy me a set I’ll give them a try :wink:
I reckon it would feel very weird on a unicycle, with the foot speed changing at the top of every stroke.


Hmm. Whiplash! (Check the same thread in JC started by evil-nick)

I converted my BMX cranks into Rotor Cranks by doing dirt jump! My old unicycle also had “Rotor Cranks” before I snapped it’s hub.

I can’t say it seemed to be much different once you get comfortable with the odd rotation. The “science” behind the idea sounds rather quack though.

If you want to try it, and have a unicycle with a splined hub, just rotate one of the cranks a few degrees and see what it is like.

If you don’t have a splined hub, do a few drops until your hub twists to the desired angle. LOL!

Are you sure the site isn’t a prank?

It reminds me of:

It presumably adds a very slight amount of efficiency for people who are riding at a very high level. It probably doesn’t reduce efficiency, or else people wouldn’t be winning races with it.

Spinning shouldn’t be a problem as you’re still spinning, just that the feet are spinning at slightly different speeds at any point. I guess their point is that even the best spinners can’t apply constant force all the way round whilst riding flat out as they inevitably can push down harder than they can push forwards.

This sort of thing is surely less important on a fixed gear anyway, as the wheel momentum pushes you through the dead spot anyway.


While reducing the dead spot for one leg, doesn’t this create a worse dead spot for the other leg?

That’s not how the Rotor Cranks work. The amount of offset is not fixed like you’d have if you had a bent hub. The offset changes throughout the pedal stroke. See the simulation here.

I wouldn’t want them on a unicycle. We control our balance by being able to make micro-adjustments to the pedaling motion. Having the cranks change in offset while you are pedaling would just mess everything up.

For bikes the concept might work, but not on a unicycle.

The Rotor Cranks aren’t new. I knew about them more than two years ago. Strange that it just hit the blogs like it was new.

There was a Cat 1 racer here in California who did a series of races on an old steel Peugeot, in sneakers and cutoff jeans, on platform pedals. I forget if he had straps or not. He won at least one race that way; I remember the interview afterwards. The point being, whether someone wins a race or not has a lot more to do with the rider than the bike, so it’s easy to introduce inefficiencies into the system and still win races.

If nothing else, these introduce extra rotating weight.

Note that they are not simply offset cranks; there’s some sort of racheting mechanism which changes the position of the cranks relative to each other during the pedal stroke.

Watching the simulation it shows how the gearing changes as the crank position changes, i suspect this would be highly tricky to ride on a unicycle, especially as effectively both your feet are on different gears, they would always be moving at different speeds (except at the cros-over point). This could seriously mess with your balance I think. The way it works is highly impressive, but I don’t think it would be viable for a unicycle.

True. :slight_smile: However,doesn’t bent cranks do the same thing for the “dead spot” though? Or am I missing something?

I’m still kind of dubious about the idea…

I think you’d learn to ride them just fine, similar to riding a two wheeler or myron cycle. It’s just a matter of time on it until you get proficient.

Well Im not expert… but considering you’d put that on a coker… that would be very pointless Im sure someone with a geared coker would go as fast as someone with that… correct me if Im wrong tho…

The only thing I can think of them being useful for are maybe muni, so you always have a pedal that can produce power, and people learning. I see a lot of people getting stuck in a no-power situation.

In any case, I’m not planning on running out and putting a set on my muni, I just wanted to know what other people thought…

Thats what I thought at first too, but its not just regular crank arms set at a slight angle…its a geared hub, so whichever crank arm is at the top is automatically slightly ahead.
I personally think it could work, for distance riding at least.

It looks promising to me. My first thought, Gee I could uni up to a curb and always be sure that I’d be in a power stroke position to ride up it.

I’m not sure about you guys, but I’ve found at least a couple decent ways to get around the dead spot.

If I’m going to be going up over a curb, I do a tiny little hop before I hit it if my pedals are in “the power position”.

Sometimes if I need to change my pedal position but can’t roll anywhere, I do a little hop in place with my pedals askew, and then align them midair.

I always thought doing things the hard way was half the fun of unicycling.

EDIT: Make that “more than half the fun”.

Extremely expensive! You’d have to modify the pricy stuff shown on that site, to an unknown cost.

Uh, don’t you ever idle or hop? :slight_smile:

But it’s true, bicycle cranks really aren’t made to handle pressure in both directions. That’s why the square taper design isn’t quite good enough for unicycles.

I think riding with those cranks would be interesting, but only the richest of rich people would likely benefit. To me, the dead spot is part of what makes unicycling the challenge it is. Overcoming the dead spot is a big part of learning to ride.

However, reducing dead spot for things like MUni or rolling trials would be very interesting. I’m sure it wouldn’t be difficult to ride with those type of cranks, you’d just need a bit of time to get used to the different foot movement. Then you could experiment with the ability to ride over terrain while never getting stuck in the dead spot!

The issue isn’t that they’re bicycle cranks; it’s that they’ve got some funky ratcheting mechanism that probably isn’t set up to provide real power in the rearward direction. And yes, that would mess up your idling and hopping, not to mention going downhill.

And there’s no way these cranks can eliminate the dead spot; the dead spot is biomechanical. All they can do is move it around.

Yes but arnt they moving it so you would never reach it??