Humanity seems convinced recumbents and mountains don’t go together. This might be the case for some recumbent designs and some recumbent cyclists, but it is not a law of nature. On the contrary, with the right design and the right technique, a recumbent can be a good and even excellent climber. Probably better than the best traditional bicycles.
The laws of physics are clear on this one. Climbing speed equals effective power divided by the total weight. The losses who make the difference between the power of the cyclist and the effective power ending up on the road, are generally not that large, and do not differ much between various bicycle concepts. Exceptions are aerodynamic drag in case of strong headwind, and rolling resistance on bad roads. However, this discussion deals with gaining height, not overcoming cobblestones or wind.
If we focus on factors that can be influenced by the design of the bike, and ignore energy losses which do not really differ between various designs, the whole physics of climbing boils down to this simple formula:
With SL-technology, the weight difference between a recumbent and a traditional lightweight bicycle is now within a few percent of the total weight. This difference is so small it could in the long run be offset by the better comfort alone, which saves a lot of energy. The difference is at least too small to denounce the recumbent as a bad climber.
However, it is the numerator which holds the secret to recumbent climbing. The body position has a large influence on the amount of air a cyclist can pump through his or her lungs. More oxygen in, more CO2 out means more power and faster recovery. On a traditional bicycle breathing is hampered by the position of shoulders and upper body. The recumbent concept leaves more freedom to optimize for breathing. I think this effect makes the recumbent potentially the best climber.
So how to exploit this benefit of the recumbent? Take a singing course and quit halfway the first lesson. You’ll know enough by then. To breath well, one needs to stand upright, shoulders to the back in a relaxed way, head up, and use both chest and belly.
Rules of thumb
This translates to a few rules of thumb for both the design of the bike and the riding technique.
- The body should be relatively stretched out. The recumbent-equivalent of standing upright is to lie stretched out. This means a relatively low bracket and a laid back seat. This goes against popular belief the seat angle should be steeper while climbing! It also means neither a full blooded low racer nor a comfort-orientated touring recumbent will ever be a really fast climber. A real climbing recumbent has the seat of the former and the bracket of the latter. The Fujin SL is a good example.
- The shoulders should be held a little backwards. This means the design and adjustment of the tiller should be such that the arms are relaxed and leave a lot of room to move the shoulders. As a bonus, the relaxed arm muscles enhance the breakdown of lactic acid. For people with short arms, an under seat or open cockpit steer can be a bad choice because of this. Also, the seat should not push the shoulders towards each other.
- The head should be held in line with the upper body. This might take a little practice, but is important to open up the chest and throat as much as possible. Users of a head rest might want to adjust it differently or even remove it before going into the mountains. It should also be taken into account when choosing a top pannier. Fine tuning of the seat helps too. Add or remove small pieces of padding until the bulge in the middle of the seat matches your body perfectly.
- The upper body should be used for breathing, not for pushing. Push only with your legs and counter these forces with your lower back. Never brace yourself with the shoulders. Relax your abs.
So why do so many people, including recumbent riders, still think the traditional bike is the better climber? The problem is, good recumbent climbing feels unnatural in the beginning. When riding gets tough, we are inclined to push harder. And to be able to push harder, we tend to sit more upright and use the upper body to apply even more force. But force is not what gets you up. It is power. Watts. It is the amount of fat and carbohydrates burnt per second that counts. And for this, you need as much breath as possible.
So it does not only take a well designed and adjusted recumbent to climb fast. It also takes practice. Go out riding and focus on breathing. You’ll soon feel the difference. After awhile the craving for breath will make a “breathing” position feel more natural than a “brute force” position.
Why am I so sure about this
This sounds like good news for recumbent-riders, but is it based in fact? Some research has been done on the influence of body position on aerobic power output. One experiment showed a significant influence of the angle between upper and lower body. Some 10% of power is lost when this angle decreases from 130~140 degrees to 100 degrees (1). There is however no difference between an upright and laid-back position (2). Only the angle counts. I suspect an angle of over 140 degrees is even better. On my climbing recumbent, a Challenge Fujin SL, it approaches 150 degrees.
Further, research has been done with traditional time trialists. An optimal aerodynamic position is not the fastest one, because the breathing is hampered by the position of arms and shoulders. A time trialist needs to accept more aerodynamic drag to give the lungs enough room (3).
The most important thing for me, however, is my own experience in the mountains. It is not scientific, I know, but I am pretty sure I’m not fooling myself. During my second journey in Scandinavia I have been experimenting with different climbing positions. I did not change the seat of the bike; I took different body positions by holding my head and shoulders to the front or to the back, and by shifting a little in my seat.
At climbs on which I took in a more upright position I had to open up the zipper of my jersey. But when I took a more laid back position with shoulders and head to the back, I had to close my zipper. It was too cold otherwise. But the cold came from the inside. It was the cooling effect of the extra air entering my chest. This air was quite cold, as I was riding at some 70 degrees latitude. So I clearly noticed the difference.
A year later, in France, I had the chance to see how big the difference can be. I was riding with a friend on a traditional racing bicycle. In the low countries he gives many recumbent riders a hard time. During this trip my bike was carrying most of the luggage: a tent, cooking stuff, both sleeping bags, mattresses and locks, and also most of his clothes. He had just a small day pack.
I had no ambition to keep his pace on the hills, and with a regular body position it was indeed impossible. However, any time I took the breathing-position, it was he who couldn’t follow. Even with the luggage, I climbed faster and recovered faster. For us it was clear the big difference came from better breathing.
I realise this article is quite radical. In fact, I say everybody was always wrong, and traditional diamond frames are bad climbers. But the idea that recumbents are inherently bad climbers, has always been at odds with the laws of physics. There were a lot of hypotheses to support the idea, but none was convincing. I think the explanation in this article finally solves the mystery. And it is definitely the best explanation we could wish for.
1 Raoul F. Reiser II, Michael L. Peterson, Jeffrey P. Broker: Anaerobic Cycling Power Output With Variations in Recumbent Body Configuration, Journal of Applied Biomechanics, Vol. 17, No. 3, 2001.
2 Steven R. Bussolari and Ethan R. Nadel: The physiological limits of long-duration human power production-lessons learned from the Daedalus project, Human Power Vol. 7 No. 4, 1989.