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Old 2009-04-29, 12:55 PM   #46
joemarshall
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Originally Posted by rob.northcott View Post
My recommendation for hill training is live on top of a big hill, work at the bottom and ride to work
Mine is to live directly west from work, in an area where the valleys are all quite steep, and run north to south. I basically have the best (or worst depending on your viewpoint) possible hillyness on my commute, given the obvious constraint of where I'm commuting to.

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Old 2009-04-29, 03:28 PM   #47
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I am having trouble myself with steep hills, of the kind you would climb with the shortest gear of a mountain bike. Being the geeky type, I tried to figure out the theoretical maximum slope you can climb with a unicycle. It turns out there's a very simple relationship between crank length (r), wheel radius (R) and maximum slope (s):

sin(s) = r/R.

So, if you know the geometry of your unicycle, you can easily draw a triangle that shows the maximum slope:


This is neat (I think) but unfortunately not quite true: it assumes that you can load all your weight on the pedal when the crank is horizontal. And you typically can't, because the critical point when climbing is the top dead spot of the pedaling cycle.

The only thing that will get you out of the dead spot is inertia: the faster you go, the further will the cranks rotate away from the top spot, and the more efficient your effort will become. If you assume that inertia will allow you to move 20 degrees from the top spot (which I suspect is reasonable) you'd have to multiply r by sin(20), like:

sin(s) = sin(20) r/R.

It's only an approximation, but it's probably enough to compare what should be possible with different wheel/crank configurations. In order to do better than this you'd probably have to do the dynamic analysis.

And, btw, there's a way to overcome this limit: grab the saddle and pull up from it as you push down on the pedal. If you can do this you should be able to climb any slope.

I don't know if this will be of any interest for anybody, but as I had been thinking about it I thought I'd share.

Cheers,

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Old 2009-04-29, 03:55 PM   #48
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That's a neat bit of maths. Although doesn't it assume that the unicycle is zero mass? Which might be a better approximation for the 20" riders than for a coker!

About the dead spot - you still have quite a lot of traction on the pedal at that point due to shoe grip, so I don't think it is the case that you only have inertia to get you past it, although you clearly can't put down as much power. Also the 20 degrees figure is surely very low - typically when it gets really limiting, you'll be doing a massive push, then pausing with horizontal pedals, and doing another massive push, and it seems like you can get a lot further round than you'd think.

And like you say, there's the saddle - most strong riders hold the saddle most of the time.

Having said that though, for a 26" (330mm radius) unicycle with 150mm cranks, the big figure gives a 27 degree slope, which would be about 50% gradient, which is unrideably steep, and the smaller (multiplied by sin(20)) figure gives an 8.94 degree slope, which is about a 15% slope, which is dead easy to ride up on a 26", so maybe the right multiplier is a bit more than sin(20) (but less than 1). Or maybe I did my calculations wrong.

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Old 2009-04-29, 04:05 PM   #49
mbalmer
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I don't know about all the math/trig stuff, but my biggest issue on a steep climb is foot slippage. One of my feet will move and mess me up on a steep section. I don't run out of strength or lungs first. I am used to bike pedals that are locked in place so when grunting up a hill I lose footing.

I also wonder how you hang on to the seat and pull up while pedaling. Do you stay seated or do you stand up? When I hold the seat I have a harder time balancing. I practice holding the seat on downhills and flat ground but steep up is hard.

I hope these problems are because I'm still new. My husband taped me climbing up a dirt trail and I was amazed at the amount of arm flailing that I did. I look like a bat.
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Old 2009-04-29, 04:25 PM   #50
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I stand up when it gets really steep. Flailing arms are something that diminishes with practice.

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Old 2009-04-29, 04:34 PM   #51
rob.northcott
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Quote:
Originally Posted by mbalmer View Post
my biggest issue on a steep climb is foot slippage. One of my feet will move and mess me up on a steep section.
I occasionally have that problem on a really steep hill (I'm used to SPDs on bikes as well, and before that clips and straps), but it's a lot less frequent than it was when I was a newer unicyclist.

Quote:
I also wonder how you hang on to the seat and pull up while pedaling. Do you stay seated or do you stand up?
I actually hold the saddle handle with one hand almost all the time, even on the flat. Off-road you need to do that to keep your feet from bouncing off the pedals, but on the road it's just a habit. On a steep climb I'll stand up and honk, same as on a bike (but still with a hand on the saddle).

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I hope these problems are because I'm still new. My husband taped me climbing up a dirt trail and I was amazed at the amount of arm flailing that I did. I look like a bat.
It'll get better - less and less effort goes into balancing as you get more used to it. But even the best riders will wave their loose arm around a fair bit on a technical off-road climb.

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Old 2009-04-29, 05:06 PM   #52
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Snake it up!

There are two useful bits of technique that have not been mentioned here.

1) If you are riding up dirt road hills or singles it is important to try and find the BEST LINE to make it up. Even small rocks and areas with steeper dirt will break your flow and cause you to use more energy. It is better to snake around obstacles or unsmooth areas rather than to power over them. Off course if you are on smooth asphalt this piece of advise is worthless.

2) Zig Zaging in order to hit the hill and attack it at a less deadly angle also helps. However you will have to pedal farther and it takes longer. Think of it like mounting perpindicular to the hill.

When pulling up on the handle you do have more power but less ability to balance and this is important on non smooth uphills. I try to avoid pulling up on the handle until it is nessesary.

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Old 2009-04-29, 06:33 PM   #53
mbalmer
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Thanks for the replies. I am on a 24" with 150 cranks. If I were on a 29" with 150 cranks, I would imagine that riding uphill would be harder.? I would also assume downhill would be easier.?? I'm saving for a new unicycle and am thinking about a 29". I wonder if I'm setting myself up for failure (on hills). It will be a while before I can buy one though and I should have a lot more practice in.
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Old 2009-04-29, 07:58 PM   #54
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Yes and no.

You would have a taller efective gear, but if you have a lighter rim/tire than your 24 it would be creating less drag. Also the larger wheel will have more inertia, so provided you can maintain a moderate pace you could end up getting up the hill w/ less total effort.

Also some of it is whichever you are used to, so when you get that bigger wheel, give yourself a few weeks to adjust to it.
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Old 2009-04-30, 07:16 AM   #55
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Quote:
Originally Posted by joemarshall View Post
Hey, I think I rode that hill*. There is an offroad track from the top of it back down to the lake right?

Joe

*I was on a 26" though
yes the track down is called "descente de l'aviateur" because there is the tomb of a pilot who crashed there. But this track is considered undoable going up (though now I have seen at Moab fairly good climbers I think are able to do it!)
on Youtube there is a video of me and Cocal riding down that one
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Old 2009-04-30, 02:55 PM   #56
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Originally Posted by joemarshall View Post
Although doesn't it assume that the unicycle is zero mass?
Yes, or that the acceleration is zero. It's the static solution of the problem, which is valid for one particular point of the pedaling cycle. Only an approximation anyway; I haven't been able to solve the full movement equation, and haven't had time to look at it numerically.

Quote:
Originally Posted by joemarshall View Post
About the dead spot - you still have quite a lot of traction on the pedal at that point due to shoe grip, so I don't think it is the case that you only have inertia to get you past it, although you clearly can't put down as much power.
You are right, I didn't think about that.

Quote:
Originally Posted by joemarshall View Post
Having said that though, for a 26" (330mm radius) unicycle with 150mm cranks, the big figure gives a 27 degree slope, which would be about 50% gradient, which is unrideably steep, and the smaller (multiplied by sin(20)) figure gives an 8.94 degree slope, which is about a 15% slope, which is dead easy to ride up on a 26", so maybe the right multiplier is a bit more than sin(20) (but less than 1). Or maybe I did my calculations wrong.
I think that you did your calculations right. Also, thinking about it, I suspect that the angle will depend on the slope. So the formula is pretty much useless, a pity :-). I'll try to figure out the dynamic version and see if one can get more info from it.

Thanks,

Juan Reyero
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Old 2009-04-30, 04:45 PM   #57
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Quote:
Originally Posted by Unicorn View Post
When pulling up on the handle you do have more power but less ability to balance and this is important on non smooth uphills. I try to avoid pulling up on the handle until it is nessesary.
An added benefit of Unicorn's suggestion is that you conserve your energy. I find this crucial for making it up longer hills.

When you pull on the handle you tense a lot more muscles in your body: your arm, your shoulder, your back. This burns calories much quicker than if you relax your upper body while climbing.

Your goal, when possible, is to only use the muscles you need to climb. Focus on relaxing your hands, arms, shoulders, even your face and jaw. Every little bit helps in the long run.
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Old 2009-04-30, 07:25 PM   #58
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I've already mentioned this earlier in this thread, but for me at least, developing some basic "trials" skills have really helped improve my climbing ability. By basic trials skills I mean being able to ride slow and in control and be able to balance in place (still stand) with either foot forward with the cranks level to the ground. Getting good at those two skills has made just about all hill climbing much easier for me. For normal grades where you don't have to stand up out of the saddle just take it easy and concentrate on one half crank revolution at a time. When the going gets steep and I'm standing up out of the saddle, to me it seems more like I've got my hand on top of the saddle sort of pushing down rather than pulling up. It least that's what it seems like to me, like the palm of my hand is on top of the handle with my fingers curled down and around the handle. And when the going is steep I just concentrate on one crank half revolution at a time, often, especially if it's hot out and I feel like I'm about to red-line or go anaerobic I'll sort of take a short pause every full revolution. These little "micro breaks" really seem to help me out. I'll even pause into a still stand for a bit longer if I need more of a breather; then continue on. Sometimes however you can't help but to redline, especially if you hit a more technical bit of ground to climb up, no problem just make sure to use the next easier bit to recover; i.e. ride slower, take a micro break or two. I've never really ridden with others before so I don't know how you all climb, but that is pretty much how I do it with some fair success.
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