Power Meter and Outdoor Consistency

Hi all, pardon me if this is a common issue, but I am new to power meter on road bike (I have used on for Ultra MTB events/pacing for a long time). I’m wondering about how consistent one needs to be in outdoor training. Let’s say you need to his 200 watts for an hour (just making something up). Indoors with Erg mode that is dead accurate, outside, I seem to vary pretty wide in where I am…dont’ know if that is just me, the nature of roads going up for down…but basically wondering (1) how closely you all manage to hold your power and (2) how to improve this.

Many thanks for your help

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What terrain do you ride the road bike on? Flat, rolling, mountains?

When I have an outdoors workout aiming for 200W, I’d typically sit between 180W and 200W. I’d also aim to keep coasting below 1 minute 30 per hour. I am blessed with pretty open roads though.

Two small points:

  • ERG mode being always spot on is just an illusion. That’s a artificially smoothed (rolling average I believe), much smoother than the real power output
  • Trying to be as smooth outside as on the trainer (steady average power, no coasting, no surging up hills, actually pushing downhill) actually could let you ride much faster when you are alone. It’s surprising how difficult it is and how many ‘valid’ reasons there are to take a mini-break outdoors :slightly_smiling_face:

Flat/rolling. I’m in Michigan

What inside trainer do you use? I have a Kickr 2017 wheel off, and on flat terrain my power graphs look almost the same as inside. But I had to turn off Wahoo power smoothing because it was lying about the actual power output.

I have the same. Guess maybe I’m assuming indoors is more consistent than it really is

Basically, close enough is good enough when it comes to this kind of thing.


You can hit your target wattage pretty accurately, just accept that it’ll fall in a range. So rather than 200, be ok with 185-215. You will tend to hit 200 on average. It’s all about shifting to keep cadence relatively the same, but that just riding real bikes outside!
Terrain matters only when the gradient is negative to the extent that you spin out. Also, if you have to stop and take turns that lowers your average. I don’t think it really matters for the body tho so don’t fret and try to over compensate to produce some number on your screen tho

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Practice. Lots of practice. It takes a bit of practice to learn to modulate your power output on flat terrain much less cutting back effort when going uphill and keeping on the pressure when going downhill. And wind adds another layer of complication.

One option might be to set up a screen on your bike computer to show lap avg power and normalized power and practice keeping those close to your target. The difference between avg and normalized power can show you how variable your effort was. Though you will want to do it on longer intervals. There are some issues with NP calculations and shorter intervals as its a 30s rolling calculation.

I generally aim to be between 100-110% of target power. I’ll end up dropping below 100% and not immediately notice which is why I aim slightly higher.

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Curious and thought I’d ask those that push TR plans outside.

When speaking of power (outdoors) are you targeting average power output I assume over a set interval or course?

I’m usually doing long Z2 rides outdoors, as I find those to be more painful and boring indoors, so usually trying to do ~215 normalized to keep at ~205 average given intersections, down hills and the like.

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That very much depends on the type of effort. If you do endurance rides, I don’t think you need power at all. I find it way more relaxing to look at heart rate and limit myself to e. g. below 130 bpm (easy Z2) or 140 bpm (hard Z2).

Furthermore, when outdoors I’d train things I can only learn outdoors. Sometimes it makes sense to go over endurance power, e. g. to keep momentum steady or because you are suddenly exposed to a gust of wind. Being smooth is much more important. If you watch your heart rate and limit your effort, you can’t go over budget in the long run. Also, you should avoid sharp spikes (e. g. starts at traffic lights).

For Z2 rides the terrain is important. E. g. I don’t think going mountain biking would be a good idea because the terrain often dictates how hard you have to go. If I want to keep it mellow, I hitch a trailer to my mountain bike, wrap my daughter in warm clothes and blankets and ride. The wife loves it, because she has a break. My daughter loves watching the scenery and the snacks that I share with her. And I work on my endurance and don’t have to spend 2–3 hours on the trainer. Win-win-win.

Another important thing to train is pacing across a whole ride, whether that be Z2 or higher. Here, things get difficult. For things like over-unders, sticking to power is much more important. So you need a suitable route (e. g. empty enough to be safe, few interruptions so you can nail your intervals, etc.). Personally, I don’t like that as much. Instead, when I ride outdoors, I set myself challenges and try to work on things that I cannot do on the trainer. For example, on my road bike that would be group riding. Or it could be pacing or cornering. These are essential skills for cyclists, and we should dedicate time to working on them.


Both, my garmin shows a power target range, so I am to be in that range for both current power and average power.

E.g. say I’ve got 300w target. My computer will show like 280w-320w. I’ll also have a ‘lap average’ field.

I try and sit on 300w and see what RPE that feels like. I then basically ignore my computer, glancing down at times at lap average to see if I’ve slipped over/under and adjust accordingly. Seems to work fine for me, having done short or long (1hr+) intervals.

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Aim for TiZ (Time in Zone). For example, say your aim is to sit between 250-270 watts and towards the end of the interval your average power is 247, don’t start riding at 300 watts to bring the average up.

Some good advice above from others.

Coming back to this and ignoring the physiology question:

Wright Peak -2 is 90 minutes of tempo (80% FTP). Here it is when I first bought my Kickr wheel-off with the default setting of Power Smoothing = ON.

That is Wahoo’s default setting. It is lying to you.

To easily compare against an outside effort, I’m only showing peak 1 hour power.

Here is another 1 hour portion of Wright Peak -2, with Power Smoothing = OFF

And here is a well paced 1+ hour tempo effort from 6 months ago, done by feel and occasionally looking down at my Garmin 530 real-time power graph. Only showing peak 1 hour as above:

There are some minor differences statistically speaking - tempo power std deviation of 12W inside vs 31W - but practically speaking it looks “the same” as the trainer with power smoothing disabled.

Completely flat course outside the city limits with only a few stop signs. Garmin was showing 198-238W as ‘green’ zone, and then another interval of 158-198W that I ignored and kept going at tempo power.

And another long tempo effort from 5 years ago, representative of my power modulation skill at the time:

You can see that over 5 years my pedal stroke and power modulation became smoother. What I’ve found is that has helped me to reduce burning matches while riding in a group setting or doing (Merckx style) time trials.

As others have said, don’t get too hung up on ‘perfect power’ while outside.

Hope that helps.

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