Can’t produce indoor power outside!

Hi all,

I was just wondering if anyone else has this issue or better yet knows how I can overcome it.

My FTP is 285, over the past 6 months that’s increased from 235ish. Due to the weather mostly all my ride have been indoors bar the last month.
Ive been following the high volume half triathlon plan. I’ve rarely missed a workout or bailed from one, and have consistently trained 10-15hrs a week since September.

My issue is… On outside rides I really struggle producing the same power.

I completed a 70.3 triathlon yesterday and on the 90km bike my aim was to hold 220w. When I did my HR and RPE shot up, and I could feel it was too high. I finished the bike leg with an average of 197w / NP203w.

I’m pretty disappointed with the outcome but it’s the first race of for 2 years, it’s was a great learning experience and lots of positives came out of the whole race.

I’m thinking that these maybe where I’ve been going wrong.

  1. I spend most of my indoor workouts in ERG mode. I should switch to resistance or get rollers?
  2. Get outside more! I struggle to do this, with a young family and full time job, my training times are very early or very time crunched. The turbo is just so convenient!
  3. In Erg mode I have the chainring is the small ring. I think I heard Nate once say that was the most optimal way. However, outside I rarely spend anytime in the small ring, would this make a difference?

Any help would be greatly appreciated.

1 Like

That’s big! Good work. I hope you can see how much you’ve done, despite your result.

How do you measure power indoors vs outdoors? Was your PM calibrated?
Did you go too hard in the swim?

For your questions, the erg/resistance modes and the chainring shouldn’t matter that much (although you’d probably find somebody here who will tell you so).

I’m sure you can continue with your convenient indoor workouts, maybe need a few 1h outside efforts to dial in why you saw those differences. For example to ride some race pace or a similar workout as you did recently indoors and compare how that goes.


Also check and double check your power meters are reading the same.

I thought I had the same problem for over a year, but turns out that my head unit outside was reading combined power from my assioma duos and my trainerroad app was only reading the left power. I have about a 5-10% imbalance in favor of the left leg so I was constantly struggling outside.


Some thoughts

  • Ride outside more :slight_smile:
  • My ftp is similar to yours, 230 when unfit and have seen it up to 280/90. Holding 220 watts for over two hours is difficult for me when at 280 (and ftp was on trainer, and outdoor rides on PM that reads a little higher).
  • this is especially the case if I’m fit from short(er) hard sessions indoors. Are you doing long training rides?
  • are you in the same position on the indoor bike and outdoor bike? if tt outdoors, normal indoors, this’ll be the issue, even if practicing indoors in tt position, it may be harder getting the power out in the tt position outside
  • If you’re using erg mode, presumably you’re measuring power indoors using the trainer and outdoors using a power meter. Could simply be one PM is in error, especially if single sided outside.
  • on some trainers you get a different reading in big and small when using erg. My understanding is that usually small ring is correct (or closer to correct) and big ring reads low. (What’s happening is that it reads low at high fly wheel speeds)
  • on some dual sided crank power meters you get different reading depending on the chain ring. I’m not sure if the big ring reads lower or higher for these. (I think GP Lama has a video on this)

I find outdoors I’ve not got the same focus over the long on power over a long term and the cognitive load takes it toll. Inside my AI FTP is 261w but the most I’ve done outside this year is 245w NP for 77mins. I have smashed my FTP very occasionally outside but I just cant get into the same zone when I can’t switch off to traffic etc. Perhaps outside rhythm is also upset by changes in cadence/ hills etc and at the start of the season I switched off ERG and operate at a more variable cadence on the trainer and I seem to have narrowed the gap that way. I mainly switched of ERG though because the Elite Suito is too variable with my single sided PM and would hammer on/off the brakes straining thing in my legs. FWIW inside I done all of my work in the small ring since I started training in circa 2015 mainly because it results lower freewheel speed/ noise and it doesn’t seem to have stopped me closing the gap or very occasionally obliterating it.

I have similarly struggled, outdoor rides at the same power as indoors always seem a little higher RPE. That’s regardless of erg or resistance mode, and I have also confirmed both my trainer and power meter are within a few watts of each other.

I can only presume the extra cognitive load and the slight variations of power on the road due to the terrain affect the power I can deliver. Perhaps I inherently associate the turbo with steady and often boring effort and accept that suffering. Whereas when I go outside, I want to enjoy it, look at the view etc etc and my mind isn’t in the right place regardless of what I try to tell myself.


So all that said, i am just aware of the gap and train accepting that.

There’s a range for all power zones isn’t there and you don’t have to be rammed right up at the top of the zone every ride.


Extra though -

wee ring indoors is more like climbing, big ring indoors more like riding fast… could be you can get more power while climbing outside

Many of these points were already covered above, but this other recent post is worth a look as well:

1 Like

Couple of things come to mind.

First, unless you are doing your workouts immediately after a long swim like you would in a Tri, it’s had to compare power output in a workout vs. expected output in a 70.3.

Second, are you using your tri bike on the trainer, or do you do your workouts on a road bike? If you are doing them on a road bike, then positioning could explain a lot. If you are using the same bike, then consider that riding outside in TT/Tri position requires additional balance and core stability, which could be an issue. From a personal standpoint I know that whenever I ride my TT bike outside versus the trainer, I feel it so much more in my glutes, because my muscle are working differently.

Third, as mentioned below, are you using the same power meter, as that can cause some really funky discrepancies.

Fourth, how is your indoor setup versus outdoors. For instance, I live in the South and if I did a right indoors in a chilled room at 4 pm, my power is definitely going to be higher than if I do it outside at that same time in 90+ degree heat.

Lastly, and this ties somewhat into the first point, but did you go out too hard on your bike split and blow yourself up? Was there a climb on the course that really took a lot out of you?

@Fletch a couple simple questions:

  • how warm was it during the bike portion of the 70.3 tri?
  • sunny or overcast?
  • course terrain: absolutely no hills except for bridges? flat? hilly?
  • for your indoor rides on the trainer, what temperature is it inside?
  • what is your longest endurance/zone2 ride on the trainer? (last I looked, the HV Full Distance plan had 5-6 hour endurance rides)


I tested the power between my cycleops hammer and stages left arm recently. I have two bikes with stages left arm.

Benchmarking to the trainer set at 200w on ERG with same gearing and cadence, one stages reads 183w on average and the other reads 192w on average.
So that’s roughly 8% and 4% difference. So if that holds across the wattage range, riding 400w on the trainer is the same as riding 368w on one bike and 384w on the other.

Sure, I might have some LR imbalance that the smart trainer captures and is missed with the left only stages arm, but still, the two stages are quite different (within reason) so there is that.

I’d say to @Fletch that your trainer just reads higher than the meter you’re running on your triathlon bike, tho other factors may be coming into play

Hey there!

Great work bumping up your FTP! 50 watts in 6 months is huge!! :muscle:

Regarding questions 1 & 3, there shouldn’t be much of a difference if you switch from ERG mode into resistance, as you ultimately still have to do the work yourself. ERG will just take care of the resistance level of the trainer without the need to shift. All that’s left for you to do is pedal!

Still, some athletes insist that resistance is the way to go for them, so it wouldn’t hurt to try a couple of workouts in resistance mode to see if that changes anything for you!

While we generally advise training in the small ring up front, it may be worth shifting into the big ring if you’re preparing for a flatter course. The big ring will get the flywheel of your trainer spinning faster, which will give you more inertia as you’re pedaling, which simulates the same feeling of putting out power on a flat (or even slightly downhill) road. Some athletes find it easier to put down power on certain types of terrain more than others, so it could be worth experimenting to see if you get different sensations in the legs by training in a bigger gear combo.

If you’re using a power meter with your smart trainer, make sure that you have PowerMatch turned on. This will allow you to train using power data from your power meter while still enabling your smart trainer to control resistance. That will take care of any discrepancies that may exist between your power meter and your smart trainer, which means you’ll have consistent power data indoors and outdoors.

Outside of your indoor training, it does sound like it would be a good idea to get outdoors every once in a while! Even if it’s only once every week or two, getting in those outdoor rides can be great practice for learning what it feels like to push out the power you need to in “real world” conditions. Just make sure to choose the best routes near you to optimize your outdoor training.

Your positioning on the bike will make a difference as well. It’s important to train in the position you’re going to race in – so in this case, it sounds like an aero/TT position. If you don’t practice holding that position while putting out power in training, it can be difficult to do so on race day.

Finally, consider the effects that the race itself may have had on you. It’s tough to compare a bike workout you did while fresh to a bike leg from a triathlon coming right off of the swim. If it’s possible, adding in some brick workouts to your training routine could help you nail your transitions.

Also remember that external conditions (weather, wind, terrain, etc.) can add up as well. If your race was hot, for example, it could be a sign that you need to dial in your hydration/nutrition for these long events.

Overall, as you said, it sounds like it was a great learning experience! Big kudos on getting back out there after 2 years, and hope to see another race report from you in the future! :smiley:


thanks for all the comments! the @mcneese.chad tread was very helpful.

I’ll try and work through the suggestions from all the comments.

  • I train pretty much exclusively on my Tri bike, the same I used on race day
  • my PM is wahoo single arm power, all rides are powermated, I try and calibrate after each warm up.
  • In the winter my max 3.5hrs on the turbo. longest outside ride was 4hrs. although, all my rides are fairly hilly, whereas my event was pretty flat.
  • I think the extra cognitive load and road conditions could play a part, they were rubbish. Lots of potholes and lots of talk of flat tyres. +1 for tubeless!
  • The weather conditions were really good for me. Not windy and not too sunny. My indoor trainer is in the garage with a simple fan. I live in Edinburgh, so it doesn’t get hot. The event was Outlaw 70.3 in Nottingham.
  • Hydrathion/fueling went pretty well, I averaged 110+ carbs p/hr, and felt great. I PB’d the run off the back of the bike… should have pushed harder on the bike:)

I have a full ironman in Italy in September - things I’ll try

  • Turbo in the big ring in and out of ERG
  • The full course is flat, living in Scotland, I’ll try find a flat longish road to do race pace efforts up and down.
  • get outside more…

Always happy to hear any further suggestions.


IIRC when I was in the ERC one of the training routes was out into East Lothian, something like out to Ballencrief/Drem and back into Edinburgh along the coast; that was fairly flat.