RChung

Right, most people not only don't know how to measure efficiency, they don't know how to measure delta efficiency. But delta efficiency is like the slope of a function compared to the function itself. As you know, the slope of a function can be increasing, decreasing, or zero, while the function itself is doing something else.

As an aside, just as slope is harder to estimate than the original function, delta efficiency is harder to estimate than gross efficiency.

PeteHski

A quick Google suggests Obree used a cadence of 93 rpm on one of his record runs. Cosworth V8 F1 engines were running at 22,000 rpm in the mid 2000s. It was the only way to generate more power with the limited capacity. Certainly not very fuel efficient!

Personally I find a cadence of around 80-85 is my optimum when riding at tempo. 60 feels way too laboured unless riding at very low power and then it doesn’t matter anyway. I certainly wouldn’t want to be riding at 60 rpm @ 250W on the flat for several hours. Even on a long climb I prefer to be well over 70 rpm if practical. At the other end of the scale I don’t like riding above 95 rpm for any length of time and usually only do so to generate power well above FTP for short bursts. At lower power, spinning at 100+ rpm just seems like a waste of leg movement!

choddo

In a training class the other day I had to do FTP at 60rpm for just 3 minutes and even that was properly ugly.

PeteHski

Exactly! It doesn’t matter how “efficient” it might be in terms of oxygen consumption or whatever metric.

RChung

Bingo. This is what @asgelle was getting at. The only way to measure efficiency is by measuring what goes in and what comes out, and most of us have never actually had that measured: but when it does get measured, it appears that we optimize over something else entirely. The bottom line is that we should almost always avoid the use of the term "efficient" as a justification for what we do when we ride. This is particularly true for cadence but also about claims of "efficient" pedaling technique. When we ride, freely-choosing cadence or crank torque or work rate, we're optimizing something but it ain't efficiency -- and that's okay.

rsbob 

Climbing with Ben O’Connor

wheelreason

I like weights, indoor high heart beat workouts, and range of motion routines. I don't do do a lot of intervals, the winter is my off season, so I'm not really looking to improve, just tweek and maintain.I find nothing makes me better at going up hills than going up hills.

Carbonfiberboy 

This efficiency thing is really quite simple and easy to understand. The definition of mechanical efficiency is the minimization of losses between inputs and outputs of the system. In the case of the bike rider, inputs are calories and outputs are kilojoules. We can measure both of those. The inputs are a bit hard to measure unless it's a multi-day effort, but the outputs are easy to measure. I'll simplify the output case by thinking only about crank and hub power meters. What they measure is torque. Our pedals are the origin of that torque. Only tangential forces contribute to torque. Therefore radial pedal forces are not seen by our power meters, and do not contribute to output.

I haven't seen a muscle activation study which shows that we actively slow our legs at any point in the pedal circle. To me, it feels like we allow the feedback in the system to help our legs change direction as they go around the circle.

terrymorse 

And easy to measure. Yet it doesn't seem that maximizing efficiency is worth caring much about.

The "goal" of competitive cycling is to cover a course in the least amount of time. I suggest that for most cyclists, it's more important to minimize fatigue than to maximize efficiency. Especially for hill climbing, where leg muscles are heavily stressed, and they don't get a recovery break.

Carbonfiberboy 

Back to the OP: To maximize my climbing speed, I keep my butt in the saddle as much as possible. On a long climb, I'll stand for maybe 1 minute every 15 to change my muscle firing pattern briefly. Although as the climb goes on and on for over an hour and I get tired, I stop standing because my legs just won't allow it anymore. For sure, standing is less efficient for me. If standing is your thing, just standing on the trainer, varying cadence and resistance to simulate various climbing conditions. And of course strength training twice a week however you climb, working every muscle that's ever gotten tired on a bike ride.

In winter, on my rollers, I do a pedaling drill once a week, otherwise just the normal stuff: a good bit of Z2 steady state and the usual intervals. I didn't ride one winter and the result was so pitiful that I never did that again. I do "start over" in the fall. I take September off the bike and hike instead. Then I start back with mostly steady state on the rollers and cross training like fast walking and running. And of course I go to the gym starting with general strength training and progressing toward cycling specific training in May. I gradually add Z3 intervals, then a little Z5, then longer Z4 and eventually the hard stuff, but by then it's spring. In April (I think that's spring) I do low cadence climbing intervals once a week. My main goal, all the time, is don't get injured. That's the reason for stuff that doesn't seem directly climbing related. I never have been.

Carbonfiberboy 

Exactly. That's the reason I TT all my event rides. I draft at every opportunity, Other than that, I think maximizing efficiency results in reduced fatigue. Makes sense to me that if all muscle activity works to move the bike forward, that does both. All muscle stress burns calories and thus contributes to fatigue, whether or not it moves the bike forward.

PeteHski

But studies have shown that radial forces are a necessary consequence of generating significant tangential forces. So radial forces do in fact contribute indirectly to output torque.

Carbonfiberboy 

No argument here. At a certain percentage of FTP, that's what happens and not a bad thing, just what happens. I'm just trying to delay that onset. I can hold that off up to almost 90%. On a long ride, like over 200k, I'd not exceed that. I tried enjoying myself in the hills once and regretted it.

PeteHski

If you have power meter pedals you can measure both radial and tangential forces. It's not a mystery and they even provide you with a pedal smoothness value, which may be of interest to you. What it doesn't tell you is whether or not a high pedal smoothness value is good, bad or indifferent. it says nothing about our biomechanical efficiency in producing the pedal output.

genejockey 

The whole "Pedaling at 60 rpm is more efficient" thing reminds me of high school physics, when you first study friction and someone will argue that car tires don't need to be so wide since the size of the contact is irrelevant.

rsbob 

They obviously never drove a 930.

DaveSSS 

In northern Colorado, I rode 492 miles with 26,759 feet of climbing, plus 87 miles indoors, this January.

terrymorse 

Brr, no thank you.

January in "Sunny and Warm" California: 24 days, 43 hours ride time, 625 miles, 54,380 feet. A mix of inside and outside.

choddo

Well that was deeply unwise

tomato coupe

The Colorado front range has pretty mild winters. Boulder high temps have been above freezing for 28 of 31 days in January, and the average high has probably been 45-50. The last 5 days have been in the 60s.

terrymorse 

Pretty big weather difference between Boulder and Loveland, though. DaveSSS is in Loveland, according to his bio.

tomato coupe

Nope. Loveland is just 30 miles due north of Boulder. (Both the Boulder and Loveland airports are reporting 63°F right now.)

terrymorse 

D'oh. I was thinking of the Loveland Ski Area, at 10,800 feet. Currently sunny and a brisk 27ºF.

tomato coupe

Yeah, but good riding there in the summer ...

terrymorse 

Yeah, I love riding there in summer. I might get up there to do the Bob Evans Bob Cook Memorial Mt Evans Hill Climb (now called Blue Sky Hill Climb) ride this year.