Why are hills hard on a bike? (unicyclist perspectives)

Note: Contains two-wheel-related content from the start.

Short question: Is there something about bikes which makes them less efficient to pedal up hills than unicycles?

Longer explaination: I’ve been getting tempted by the benifits of bikes (for road/touring) lately. You get exactly the gearing you want, less wind resistance, loads of luggage space, freewheeling down hills…

But uphill seems much harder on a bike than a unicycle - even a 36er with short 102mm cranks. Everyone seems to describe passing bikes uphill on unicycles.

I had an experiment when I borrowed a lightish road bike (little heavier than my 36er), and pushing hard over an 18 mile route with 300m+ elevation I could only manage an average of 13.5mph, where I’ve averaged 15.3mph on my uni on the same route before now. I was sure it would prove to be much faster, as on the level I was cruising fast and, well, it’s a bike!

Shifting down gear to go up hill seems to make everything go wrong on a bike - I didn’t have the energy to stay standing on the pedals despite trying to tell myself to, so was reduced to using only thigh muscles and near granny-gear spinning speed (bottom of the middle set of 27 gears).

Can bike-riding unicyclists (I know you’re out there) explain this for me please? Is it the geometry of a bike (less upright than a uni, so using less body weight on the pedals?), or the efficiency of unicycle’s direct fixed drive? Or is it simply in the mind - pushing a uni up hill can be burning murder, but when there are no other gears you just keep pushing? I used to assume it was just the weight of a bike, but on a light bike this is not significantly different?

Cheers,

Sam

P.S. This experiment has convinced me to stick with one wheel - much easier!

I think the answer is that they’re not.

The reason why unicyclists tend to pass bicyclists uphill is simple. Many bicyclists, when they go up hill, tend to choose a lower gear to make it easier. Unicyclists do not have this option, so instead, we get stronger, and we become faster because we tend to maintain a minimum cadence. Given a bicyclist and unicyclist of the same fitness and strength, the bicyclist will still be faster uphill.

The reason why YOU might be faster on a uni is simply because you are currently a stronger unicyclist than you are bicyclist.

Gear ratio. Most common bikes at 1:2.5. That’s 40% the torque, for 2.5 times the speed of a normal 20". So you got way more torque to maintain a good speed, while that biker is struggling to get up the thing. (Imagine pedaling a unicycle with wheel 50 inches in diamter. It’ld be tough.)

-Shaun Johanneson

I don’t quite get your post. Are you saying that you get 40% less torque on a bicycle but you go 2.5 times faster…or the other way around?

unicycles are much faster for climbing.
while your body position above the cranks is very similar to a standing biker, but all your weight is on the pedals, some of the bikers weight is resting on the handlebar. less effort is lost in the drive train of a unicycle.

On big hils when the biker in the granny gear, they have a 1:1 ratio just like us. Our advantage here is shorter cranks, and a fixed drive. when you force one pedal down, your foreward momentum brings the other pedal into the power position, for this reason much shorter cranks work fine on hills allowing you to spin much faster than a bike.

I’m usually not much of fan of riding uphill on a unicycle, but passing guys on 3,000$ xc bikes makes it worthwhile.

I find it easier to go uphill on a bike.

There’s a knack to riding a bike. Going up hills fast I tend to use quite a low gear, sit down and spin like crazy. I did a similar experiment on the Penny Bike of Doom, which weighs about twice as much as my coker, but which I’m quite used to riding around, I can average 19-20mph over 5 miles on the bike, which I surely can’t on the unicycle.

The trick I think is going down to not too low a gear, and keeping up the spinning like crazy thing. Having the seat the right height really helps for this I think, nice and high, so you’re in a similar position to on a unicycle and can push properly.

Maybe the reason you were slower is in your post - you say ‘freewheeling down hills’. That’s why bikes have big gears, so you don’t have to freewheel down hills, you can keep pedalling up to at least 40mph on most road bikes. Even on the Penny Bike, I run out of gears at something over 30mph.

A simple way to look at it is that you’re easily in the top 1% of fitness levels in the UK, well up there with most ‘serious athletes’, yet most club bikers on a time trial would average significantly more than you do on the unicycle.

I do find riding a bike 10 miles feels like harder work than a unicycle 10 miles, but that’s mainly because I ride as hard as I can pedal on the bike, whereas on the unicycle I have to keep it in control too.

Joe

ps. Unicycles are however fantastic for when you are forced to spend the start of the year in a warm sunny country in the southern hemisphere, and need to take something on the plane. Oh yes they are. Very nice way to get to the beach, particularly when there’s 30km of hilly singletrack between you and the beach, oh yes I’m not smug in any way.

Let me just get this out of the way: it is 100% absurd to claim that unicycling is more efficient than biking at anything, including riding uphill on roads. Really, truly ridiculous. The amount of energy wasted by the wobbling motion of unicycling, plus the amount of energy required to maintain balance, is much, much larger than any small advantage unicycles have in weight, which is our only advantage.

Look at it this way; let’s put the strongest uphill unicyclist in the world (Kris Holm, Mike Tierney, whoever your favorite is) up against Lance Armstrong on a hill climb. Who’s your money on?

To further the point; how many other bicyclists do you think would beat Kris or Mike up the hill? The answer is, every bicyclist who is at or near their fitness level. It would not be close.

In the Bay Area, Glenn Drummond trained every day on Mount Diablo, our biggest sustained hill climb (1150m). He built a custom, all carbon-fiber Coker and did a tubeless conversion to compete in the Mount Diablo Challenge. He finished in 1:13, by far the fastest time ever turned in by a unicyclist in this race (and his competition includes the Hoovers, Scot Cooper, and other noted big-wheel unicyclists). That meant that only 317 bikes were ahead of him. The winning bike time was 48 minutes–25 minutes faster.

Yes, unicyclists pass bikes on uphills, but only because of unequal fitness levels. I can ride a unicycle uphill faster than many people can ride a bike uphill, but I can ride a bike uphill way faster than I can ride a unicycle uphill. (My time difference on Mount Diablo is about 20%).

The speed difference between bikes and unicycles is smallest on uphills, but bikes still win, hands down, based on simple physics and every empirical test.

Well I’m a biking unicyclist who’s also ridden singlespeed bikes up hills, so shut it the rest of you. :slight_smile:

I think there are two main things:
1)When you have gears, it’s very easy to choose a lower gear that lets you gently spin up the road in a roughly 1:1 ratio. It’s possibly the most efficient way of climbing, but it isn’t that quick. When I was riding a 2:1 singlespeed up big hills, I was faster - to keep it going, you have to keep a certain cadence or you stall, so it forces you to work harder. Unicycles are the same - go fast, or get off and push. It does mean if the hill is higher than your fitness gets you, you fall of absolutely shattered before the top.

2)You’re a unicyclist. It’s all cycling, but the muscles used are not quite the same. A long ride on a bike after ages riding only unicycles lots will make your legs hurt, and vice versa. Ride bikes more, and you will get faster on a bike. The unicycle muscles do help because the major muscle strength is there, it just takes time to adapt a bit.

3*)fixed gear cycles have some advantages uphill, allegedly, because your momentum carries you through the dead-spot of the pedal revolution. Despite this, my bike’s keeping all of it’s gears.

It’s not gear ratio (bikes choose the gear they want), it’s not weight distribution (a biker pulls up on the bars when climbing, putting more than there bodyweight on the pedal - same as a unicyclist with a handle). It’s not drive train efficiency (dérailleur gears are about 99% efficient).

Brief summary - bikes aren’t slower, you were just being a big jessie. Go and try harder. Stay seated, find a gear where you can just sit and spin without too much effort, then shift up a few gears. And I agree with Joe about pedalling downhill.

And don’t knock people on $3000 bikes. Without them, bike companies would have less R&D budget, and the normal stuff wouldn’t be as good or as cheap as it is. It also leads to a marvellous second hand market.

John

*No one expects the Spanish inquisition

Calm down. Same rider, silly level of fitness, 18 mile route- unicycle 2mph faster than a bike. It’s not that much of a silly claim.

But not the same amount of familiarity and skill on the bike. It takes time and practice to get good at climbing on a bike. Technique is different, muscle groups are different.

If you spend equal time on a bike and a unicycle you will be faster on a bike.

I did an experiment climbing a dirt road hill on my MTB and my muni. I’m faster on the bike even though my biking skills are way out of practice. But what’s more telling is that I’m less tired at the top when riding the bike despite being out of practice on the bike. On the muni I am pushing myself to cardiovascular max. On the bike I still have reserve but no longer have the technique to tap it. If I was in proper training on the bike I could blow past my muni riding self easily by a wider margin.

The same would be true on a road bike on paved hills. Compare yourself to serious club cyclists who ride regularly, just like we ride regularly on our unicycles. Club cyclists can be quite fast and would smoke any unicyclist in a hill climbing contest.

Ride the bike seriously for several months and ride with some club riders who can give you tips on technique. Then go try that 18 mile ride again. You’ll be way more than 2 mph faster.

18 miles for anyone semi-fit on a flat-ish course should be under an hour on a bike. to do that on a unicycle would be really really fast.

thats probably because you get a head start and get momentum to help you keep pedaling up. go up on your bike from a dead stop at the bottom of the hill. then do the same thing with a uni

Your claim here is that it’s easier to mount a unicycle facing uphill than it is to mount a bike facing uphill? Have you ever done it?

To understand why your unicycle seems more efficient up hills you need to compare like with like.
Both unicycle and bicycle are very efficient machines, and what you really mean by “more efficient up hills”, is “easier to ride up hills”.
Because both machines are very efficient, the efficiency that matters is how well you are using your muscles.
So: a fair test would have a unicycle against a bicycle. The bicycle would have gearing set such that both machines travel the same distance on one pedal revolution. Crank lengths would be set to be the same. Machine weights we will make the same. Efficiency is very high for both machines, so let’s ignore any losses here, treating both machines as 100% efficient, and think what else could make the unicycle appear to climb hills easier.

Simple physics: Work = force * distance. The force is of course variable through the pedal cycle, but both cycle and bike are using the same mechanism here so we can ignore the variations through the cycle, and simply say work done is proportional to force applied times distance.

The distance is the same for both bike and uni, and is a function of the crank length. So the only thing that can differ is the force applied.

On a bike the maximum force you can apply to a pedal is your full weight. You can stand on the pedal. You cannot apply more force.
On a unicycle, if you have a handle and pull up on it, then you can apply a force to the pedal which is considerably in excess of your weight. So you can actually work harder on the unicycle, putting more energy into the machine, by putting more force onto the pedal. As such you will find you can climb steeper hills than on a bike. And it may well seem easier, although the reality is that you are working harder, using more energy per second to propel you and the unicycle uphill.

Nao

This isn’t a flatish course, 1000+ feet of ascent he says.

But yeah, from the sound if it, there are quite a few bike riders out there who could beat Sam on that route, I think I’ve done routes with that much ascent at faster speeds that that when I rode the bike regularly. I’ve certainly never been anywhere near as fit as Sam in general, over 15mph on an hour long route with big hills is mental fast.

Joe

You can use the bars to hold yourself down and apply more force than your bodyweight. I reckon this allows you to pedal way harder gears than you can on a unicycle.

Anyway, you’ve simplified out the major advantage of bikes up hills, which is that on a bike you (generally) have gears, if you are in a lower gear, you don’t need to apply more force, you can increase the amount of work by spinning faster.

On a geared unicycle I know in low gear I know I go faster up some hills that I am able to go up in high gear. Sometimes spinning allows you to do more work than mashing away at the high gear.

Joe

This is complete hogwash for more reasons than I can mention. But to begin:

  1. It is no easier to pull up on a unicycle handle than to pull up on a bicycle handlebar/brake hood.
  2. Downwards force on the pedal is not the limiting factor in hill climbing.
  3. For a given downwards force, bicycles are much more efficient at translating it into forward momentum than unicycles. If you put 100% of your weight onto a single unicycle pedal, well, you would fall off, but before you fell off, the unicycle would turn perpendicular to the road.

You might want to start with observation (it is easy to observe that unicycles can’t ride up hills as fast as bikes, and bikes can ride up steeper hills than unicycles) before you get to theorizing.

Surprising that this discussion is going on as long as it is. Some of you guys don’t seem to spend enough time around bikes or something.

Like Tom said, compare the experts. But what I’d like to compare is the pre-retirement Lance Armstrong on the unicycle, and Kris Holm (or the ultra-fit unicyclist of your choice) on the bike. Sure, that would probably put Lance to the top first. But then when they switch back Lance would still be to the top first.

If you really want to compare, you have to use the same rider, with equal practice time and fitness level on both vehicles. Then if you really want to get scientific, measure their power output, oxygen consumption or whatever measurements are taken to compare how much actual physical work is being done on each cycle.

A bike isn’t the more efficient vehicle for going up hills because it has gears. It’s more efficient if you know how to use them to your advantage. Even with a Schlumpf, if you’re riding up all the hills in the big gear, you have to ask yourself what you spent all that money on.

Two words: Clipless pedals.