Unicycling myths

[OneTrackMind]

@Klaas Bil

When you hit a bump, both pedals will rise an equal amount because of it (not regarding the “orbiting” motion of the pedals which is expected anyway, bump or not). So assuming you have both feet on the pedals, the uni pushes up against both legs equally, the effect on forward speed being neutral. Similarly for a dip, the effect is also neutral.

Yes, assuming you have the weight equally on both pedals.

With experience, if you see the bump beforehand, you compensate automatically.

Maybe you should take a look at the thread I started about riding in the dark.

[Klaas_Bil]

@Klaas Bil

When you hit a bump, both pedals will rise an equal amount because of it (not regarding the “orbiting” motion of the pedals which is expected anyway, bump or not). So assuming you have both feet on the pedals, the uni pushes up against both legs equally, the effect on forward speed being neutral.

@OneTrackMind

Yes, assuming you have the weight equally on both pedals.

But that is exactly the point! If you are not aware of any bump you will have roughly equal weight (force, really) on each pedal. If you have unequal force (more on the front pedal immediately before and during hitting the bump) because you see the bump coming, that is exactly the sort of compensation you need to do.

Maybe you should take a look at the thread I started about riding in the dark.

I read that already (mainly because I didn’t understand “seat of your pants” :)). You write how you learned to compensate without much visual input. That only reinforces the point that visual input is important to do the right thing when you see a bump beforehand. I did not mean to write that one cannot ride over a bump without seeing it coming, but you will agree that it makes it harder.

[OneTrackMind]

@Klaas Bil

If you are not aware of any bump you will have roughly equal weight (force, really) on each pedal.

Not quite. When the rider puts more weight onto the pedals, as the wheel hits the bump the body moves forward transferring the weight to the front pedal in a way that does not happen so strongly with most of the weight on the seat.

You write how you learned to compensate without much visual input. That only reinforces the point that visual input is important to do the right thing when you see a bump beforehand. I did not mean to write that one cannot ride over a bump without seeing it coming, but you will agree that it makes it harder.

Definitely. However the propensity to overturn when riding blind seems to relate less to the bump itself than some other factor. I suspect it is crank angle. If you happen to hit the bump with the cranks vertical then there is no transfer and no automatic compensation.

[Klaas_Bil]

@OneTrackMind

Not quite. When the rider puts more weight onto the pedals, as the wheel hits the bump the body moves forward transferring the weight to the front pedal in a way that does not happen so strongly with most of the weight on the seat.

OK, I see the point. If you “stiffen up”, then your body moving forward causes more force on the front pedal. Ditto when you hit a dip stiffened up, your body would move backward (relative to the wheel) and puts more force on the back pedal. Instinctively when riding offroad in the dark I “stiffen up” to some degree. I always thought that that makes the muscles more alert, and I still believe that is an effect. But now I see how it ‘automatically’ compensates for bumps and dips, without additional muscular input.

Definitely. However the propensity to overturn when riding blind seems to relate less to the bump itself than some other factor. I suspect it is crank angle. If you happen to hit the bump with the cranks vertical then there is no transfer and no automatic compensation.

And hardly any voluntary compensation either. In the so-called dead spot there is little you can do. One reason more to use your eyes if you can, so that you can “pre-compensate”. I guess a skilled unicyclist makes all these calculations in the background, without even knowing. Isn’t that clever.

[OneTrackMind]

@johnfoss

Cruising with the seatpost actually leaning forward is a pretty unnatural position, not comfortable, and kind of scary if you’re bending back at the waist. It can work fine if the unicycle seat is rear-of-center over the post, like on my old carbon MUni with the Thudbuster Uni-pivot seat post. On that one, the seat hinges up and down to the rear (with an elastomer). But even on that one, the frame doesn’t lean forward unless you really sit up straight.

In this case, even with the frame tube itself leaning forward, the effective caster angle is still positive.

It is essentially just a bent frame. If you draw a line from where the rider sits to the axle, which is the steering axis, it will still be leaning backwards.