I've ridden a recumbent a few times and noticed that going uphill is very, very slow. Given that recumbents are supposed to be more efficient than diamond frame bicycles, why are they so darn slow uphill?
Related: does "efficiency" mean something different when applied to recumbents?
"Efficiency" seems like it should be easy to measure. Power out ÷ Power in. Obviously nothing in life is so easy.
Here's a blog post by a randonneur who has compared power output on his recumbent to that on his diamond-frame bike (there are some related posts at the end that are also interesting).
He's found that his peak power output is higher on his DF bike, but his calories per mile and his watts per mph are lower on his recumbent. So those are a couple of non-obvious ways to define efficiency that show the recumbent being more efficient.
The author also writes about feeling "muscle-limited" on recumbents due to his inability to recruit as many different muscle groups, and "lung-limited" on DF bikes. And there's some interesting discussion in the comments.
Bike geometry and bio-mechanical topics have been discussed by others already, but I wonder if a large part of what you're observing is a relative difference between speeds on the two types of terrain?
Think of it this way:
You ride a "regular" bike on the flat. Your ultimate top speed is essentially governed by aerodynamics. You reach a speed where the force of the air you're pushing against equals the force you put in.
When you ride a recumbent under the same conditions, it's more aerodynamically efficient, so your top speed is higher.
Makes sense.
Going uphill it's a little different.
A larger part of your input energy goes in to overcoming gravity. Which is why your top speed will be lower.
Riding a recumbent uphill, you're still overcoming exactly the same amount of gravity, so aside from other mechanical advantages a recumbent may or may not give you in this situation, your top speed will be roughly similar to riding any other type of bike. The aerodynamics play a much smaller part in the equation..
Summary : the relative difference in the two top speeds is going to be greater (and more noticeable) on a more aerodynamically efficient machine.
Caveat: I'm neither a scienctist, nor a recumbent rider :P
Not sure why it hasn't been mentioned in the other answers but recumbents are generally much heavier than traditional frames and on steep gradients weight makes a big difference.
Looks like a 2000$ recumbent is around 30lbs and a 2000$ road bike should be around 18lbs or so.
Efficiency i.e., not wasting energy, is not the same as allowing high power output.
I thought recumbents were efficient because of low aero drag compared to a conventional bike.
With respect to power output, my guess would be that when riding a conventional bike out of the saddle, the arms pull against the bars as the feet push against the pedals, allowing the musculature of the whole body to contribute to power output. When riding a recumbent only the legs can contribute, hence the higher potential power output of a rider on a conventional bike.
Recumbents are generally heavier than a non-recumbent bike designed for the same kind of riding and sold at the same price.
With a few exceptions (mainly FWD MBB ‘bents), a rider of a ‘bent cannot use upper-body strength to apply additional power to the cranks.
Most riders who have “ridden a recumbent a few times” are not appropriately conditioned to drive the recumbent as efficiently as they are to drive a non-recumbent bike. Becoming properly conditioned and learning the proper pedaling/riding technique is often referred to as “getting your ‘bent legs” which gradually occurs over a period of a few weeks to a few months. If I spend a lot of time riding one of my ‘bents with a low bottom bracket and then go back to riding one of my ‘bents with a high bottom bracket it takes me a week or so to acclimatize again because even that hits my leg muscles differently; it’s a bigger change to go from any non-‘bent to any ‘bent. Until you get your ‘bent legs, you notice the difference mostly when going up steep hills.
The primary advantage of a ‘bent as far as efficiency goes is the superior aerodynamics. First, not all ‘bents actually have superior aerodynamics: My Sun EZ-1 Lite shopping and utility bike is less aero than my old Schwinn. Second, aerodynamics have almost no effect at the slow speeds at which hill climbing occurs: Below about 15mph (combined forward travel speed and wind speed) the aero profile is essentially meaningless and if you’re going faster than that you’re either a serious athlete or not climbing a real hill.
On any bike, the legs are almost straight when the pedals are at the farthest point away. Now, think of the reverse, when the pedal is closest, on a bent your upper legs are at about 90 degrees from your abdomen whereas on a DF your upper leg is almost parallel to your abdomen. Therefore on a bent your big glute muscles are already half extended as you start the power stroke, whereas on a DF you have full use of those muscles at the start of the power stroke.
I am fairly new to bent riding and have come to accept snail speed on hills, on group rides I keep up otherwise, and everyone seems to accept that, for me, the price of still biking in my senior years is slow on uphills! I do love being pain free!
I've done a decent uphill ride last weekend on my recumbent, and have two realisations:
1) Its hard to ride for long when your feet are above your heart - I was getting numb toes until the grade levelled out.
2) There's a minimum speed required to keep your balance, and if you can't do 5 km/h then you're going to be too wobbly and all over the road.
I have a 22 tooth grannie chainring and its too small to be useful. So I sit in the 32 tooth middle ring and a 32 tooth rear gear and grind away at that.
I've done this climb in 35 minutes on a road bike. and 42 minutes on a bad day. This recumbent ride took 59 minutes, and admittedly my heart rate was below 150, whereas it was in the 170s on the road bike.
Upshot - recumbents ARE significantly slower up hills.
Aside - doesn't help that my steel recumbent weighs 20 kg. My 11 kg aluminium road bike feels like a feather by comparison. And fancy race bikes feel like nothing-at-all. So that added weight doesn't help one's uphill speed at all.
Two answers here, from a 30 year 2-wheeled recumbent (bent) rider. One, in your particular experience instance, you have not developed the necessary muscle groups used riding recumbent. This takes weeks or months to fully develop. On a bent, you are using the same group constantly. You must develop that particular muscle group. On a diamond-framed bicycle, when you stand, you are using some different muscles which are less fatigued ("fresh"). A combination of these two factors means that climbing on a bent requires gearing down and "spinning." We cannot use any upper-body strength at all. It's ALL legs, ALL the time. Bents do climb slower. There's no denying that. We downhill far faster, and on the flats, we are also slightly faster. On a bent, clipless pedals will provide an 'overdrive'. Mostly, when I'm clipless I only really use the extra pulling power on hills. This gives me a fresh muscle group to use, and increases climbing speed, marginally. This is one reason it's hard for Bents and diamond-framed bikes to ride together. We're slower uphill, and we blast downhill. So, grouping diamond-frames and Bents means the diamond-framed rider might have to slow down uphill, and the bent rider needs to slow down on descents, or we're just constantly passing each other all day.
One thing to consider is that on a Diamond frame bike you can stand on the pedals when going uphill to use your mass as an advantage. Some people may even do this unconsciously. That sort of thing is not really possible on a recumbent bike.
