# Power vs. cadence



## heedongyee (Nov 29, 2010)

Anyone have any (links to) graphs for power vs. cadence? I'm curious how fast the power falls off when a cyclist deviates from his/her optimal cadence. Is the "powerband" different for sitting and standing efforts? I wonder how much you give up by running a wide range cassette or even a singlespeed. I imagine this is different for every rider, but some general info would be useful.


----------



## Wookiebiker (Sep 5, 2005)

Power is simply a component of torque and speed (Pedal RPM's) ... The faster you pedal the less torque you need to achive the same power ... or the slower you pedal the more torque you need to achieve the same power.

When you see power drop off, it's generally because people get bogged down in their gearing and can't generate enough torque or speed to compensate one way or another (or spin out on a downhill, which isn't a big deal because you can carry speed by coasting and going aero). What that RPM is for the drop off will vary from one rider to the next.

A wide range cassette will likely help people keep their power levels up, but may result in an uncomfortale situation when pedaling because they can't find their own "Sweet spot", but are still able to put out normal power outputs.


----------



## Schneiderguy (Jan 9, 2005)

*Wookie I'm Torqueless*

any suggestions as to rpm and length of intervals to increase power through more torque? I spin pretty well naturally and years of riding.


----------



## spade2you (May 12, 2009)

How wide of a cassette? What's the front crank? What kind of riding/racing and terrain? 

Personally, I like a 11-25 Campy 11 speed cassette on a compact.


----------



## Wookiebiker (Sep 5, 2005)

Schneiderguy said:


> any suggestions as to rpm and length of intervals to increase power through more torque? I spin pretty well naturally and years of riding.


Well, one thought would be low cadence climbing. It doesn't have to be a steep hill, just climb in big gears to help build strength. Keep your RPM in the 60 RPM range and the resistance hard.

The other would be to work on shorter VO2 max intervals in the 1 - 5 minute range. Hard pedaling for that duration will help build up strength.

With that said, if you are a natural spinner ... the key is to make sure you have enough gearing for the terrain you ride. Given that you can get gearing as low as 34x32, that should allow you to spin up most anything. You can run a 12, 13 or 14 tooth small cog on the back if you can spin at high RPM to help keep the gear ratio's closer. 

In the end it comes down to power, regardless of how you make it (high or low RPM). Work on that and you will be fine


----------



## Poncharelli (May 7, 2006)

Anyone have any (links to) graphs for power vs. cadence? That should be a quadrant analysis graph I believe. (?)

There was one canadian elite MTB coach that said that power does not really drop off till <60 rpm on the low side. He's observed that from looking at numerous power files. This was to answer the question why riders seem to place well with a singlespeed within a geared group. Power seems to be conserved within a reasonable rpm range. 

My best 20min power output ever was during a insufficiently geared uphill (10%, at ~68rpm average; grinding with some standing). Even though I put out great power at that rpm and riding position, it would be terrible to use that rpm during a crit, due to aero drag and added difficulty of responding to surges. 

Optimal standing rpm is lower than optimal sitting rpm, for sure.


----------



## kbiker3111 (Nov 7, 2006)

Schneiderguy said:


> any suggestions as to rpm and length of intervals to increase power through more torque? I spin pretty well naturally and years of riding.


If it truly is neuromuscular power you're lacking:
Why we don't use strength-endurance anymore — aboc Cycle Coaching


----------



## Alex_Simmons/RST (Jan 12, 2008)

Wookiebiker said:


> Power is simply a component of torque and speed (Pedal RPM's) ... The faster you pedal the less torque you need to achive the same power ... or the slower you pedal the more torque you need to achieve the same power.


Just to expand a little further on this....

While power = torque x cadence

that's really a function describing how we _measure _power, rather than how we _generate _it.

_We don't really have control over cadence per se_. You cannot independently change cadence without also changing the forces being applied, they are not independent variables.

_What we can control is the effort we are putting into pedaling (power), and the gear we choose_. Cadence is then an outcome of those two things, combined with the resistance forces acting against us (gravity, air resistance etc).

IOW, cadence (per se) is a red herring. Focus on effort level (power) and choose a suitable gear, and/or one that is specific to the circumstances you might face in your goal event(s).


----------



## wim (Feb 28, 2005)

Here are some fairly good graphs on power, torque and cadence. Note that for trained riders, maximum power occurs at very high cadences, which is something you see illustrated on the track all the time.

Also consider that you asked about "optimal cadence," which I understand to mean "most efficient cadence". Since long-term maximum efficiency (what a touring rider is after) is not short-term maximum power (what a track racer is after), the graphs I linked may not be of much use to you. Not sure if there are any good graphs relating cadence to long-term efficiency.

Bicycle efficiency and power -- or, why bikes have gears


----------



## looigi (Nov 24, 2010)

Maybe this is getting over-thought? Torque and/or power vs RPM is done routinely for engines and I think that's what the OP is asking about for cyclists. It'd be simple graph, rpm on the X axis and power or torque on the Y axis. Certainly the conditions of test would need to be completely described, like duration etc., but it would something like this, for max short term power:


----------



## Alex_Simmons/RST (Jan 12, 2008)

looigi said:


> Maybe this is getting over-thought? Torque and/or power vs RPM is done routinely for engines and I think that's what the OP is asking about for cyclists. It'd be simple graph, rpm on the X axis and power or torque on the Y axis. Certainly the conditions of test would need to be completely described, like duration etc., but it would something like this, for max short term power:


That chart shows the relationship one would expect for very short duration maximal efforts, but who thinks riding at such a cadence (120rpm) would be "optimal" when riding a TT, or doing an endurance training ride?

Nobody. Which just goes to point out that the search for an "optimal cadence" is a fruitless exercise. Take another rider - and you'll find their peak power occurs at ~ 130rpm. Again not optimal for anything other than peak power production.

What's "optimal" (however one might define optimal) will depend on the specific circumstances, such as absolute and relative power output, nature of the bike, set up, terrain and gradient, standing, sitting, type of race event, level of fatigue, how relatively fit we are etc etc.

IOW, there is no "optimal" cadence.

Probably the best explanation is by Robert Chung in this item, which also contains further links to work your way through the narrative:
Optimal cadence and power data


----------



## heedongyee (Nov 29, 2010)

Thanks for the graphs, wim and looigi!


----------



## Etod451369 (Apr 22, 2012)

Agree with the above, when people talk about power and try to compare themselves against something it just doesn't work. A bit like when you hear people say I do 290 watts....OK, but how much do you weight?

Here are two data sets for me. 1 is pretty much my normal cadence and 2 is bigger gear (slower cadence)

1. Power 216/ Cadence 93/ Ave Speed 16.6/ Time 20mins
2. Power 240/ Cadence 86/ Ave Speed 16.0/ Time 20mins


----------



## serious (May 2, 2006)

heedongyee said:


> Anyone have any (links to) graphs for power vs. cadence? I'm curious how fast the power falls off when a cyclist deviates from his/her optimal cadence. Is the "powerband" different for sitting and standing efforts? I wonder how much you give up by running a wide range cassette or even a singlespeed. I imagine this is different for every rider, but some general info would be useful.


But the trick is to find your optimal cadence, no? With gears, I believe that I am around 84-87 but I seem to be able to maintain similar power for 20 minutes at much lower cadence as well, with enough out of saddle time. 

But unlike the suggestion in the article that low cadence training may not provide much benefit, it certainly helps me, since I race single speed mtb and I need to be comfortable mashing at low cadence.


----------



## spade2you (May 12, 2009)

I think to a certain extent, a given rider will have an optimal cadence and a variable effective range. I think training above and below is generally a good idea as part of a training plan.


----------



## looigi (Nov 24, 2010)

Alex_Simmons/RST said:


> That chart shows the relationship one would expect for very short duration maximal efforts, but who thinks riding at such a cadence (120rpm) would be "optimal" when riding a TT, or doing an endurance training ride?...


Of course, as mentioned in my post the test would need to be completely described, like duration etc. It may not be easy or fast to generate a similar graph for TT type efforts (perhaps some constant VO2 percent or lactate level?) because you'd have to do the experiment for each cadence over periods/conditions that would be similar to a TT. 

IMO, there's no question that it is a valid question to ask and that the data could be obtained. There is a question of how you would interpret that data and best put it to use.


----------



## Kerry Irons (Feb 25, 2002)

*Optimal*



Alex_Simmons/RST said:


> What's "optimal" (however one might define optimal) will depend on the specific circumstances, such as absolute and relative power output, nature of the bike, set up, terrain and gradient, standing, sitting, type of race event, level of fatigue, how relatively fit we are etc etc.
> 
> IOW, there is no "optimal" cadence.


So true. It is interesting to note that all the world hour records set in the past 50 years or so have been at right about 100 rpm. You can consider the conditions to be flat road, no wind. Clearly these efforts were at very high power outputs for a full hour, though of course nothing like close to sprinting power.


----------

