Valuing time on trainer vs. riding outside?

I’ve done a little research on this question, but haven’t really found a consensus — although I don’t truly believe a consensus exists. With that being said, I’d be interested to hear if anyone here regularly uses a multiple (I.e. 1.5x, 1.15x, etc) when calculating their training time, or TSS, on a trainer vs. riding outside.

The reason I ask is, for reasons mainly due to the weather in Chicago, I’ve found I’m in the longest stretch I’ve ever been in without riding outside, and the density of my trainer-based workouts is really growing. I’m now approaching 500-600 weekly TSS of base training, but doing so in 8-10 hours of training. +/- 600 TSS is about the maximum range I would regularly hang out in during the summer, but I’m currently doing this in <10 hours on the bike, where in the summer I’d be riding ~12+ hours to achieve the same.

For reference, I’ve pasted my last two weeks of training below. I kind of value time on the bike more, or at least as much as TSS … but I feel there is an imbalance now. I know the answer to this is to ride longer/lower on the trainer to balance this out — and while I’m not opposed to long trainer rides… “long” for me (on the trainer at least) really caps out at about 3 hours. Just like everyone else, I find it mentally grueling … but I also feel I’m better than most at doing 2+ hour rides. I’d do a 4 hour ride on a trainer, but that would be a one-off and not something I could do with regularity.

I don’t know … I guess my question is: should I be given myself more credit for “time on bike” due to the time being 100% trainer based?

I’ve heard the podcast crew (and Keegan) discuss this from time-to-time … and I believe they’ve said that time on a trainer is something like 50% more productive than time riding outside (I.e. an hour ride on the trainer is like a 90 minute ride outside). I’ve also read articles that mention multiples like 15%-20% more productive.

I know this is HIGHLY dependent on a multitude of variables … but just curious if anyone regularly logs the value of their “time on bike” differently when on a trainer vs. outside.

This feels like a rambling question. Apologies to the TL;DR crew🤘

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The day I stopped worrying about quantity (TSS, hours) was the day it let me focus on quality and made improvements and get over fitness plateaus. It used to kill me to ride below 500 TSS per week and now I average much lower TSS. Yet still breaking my PR records every year at almost 39 years old (been riding since 2015 and with a power meter / training mentality from the get go) My best race result and average power / weighted average power for an hour came after training 5 hours a week with trainerroad as opposed to riding outside 10 hours / week.

So! I would keep focusing on making progress in trainerroad and not stress about the total time on bike or TSS totals too much. OFCOURSE, there’s value to be had with added volume. But it shouldn’t be by sacrificing quality training. If you can add volume without disturbing what you’re doing already or disturbing your personal life, sure! Why not! But otherwise, keep at indoors and you’ll enjoy the results.

Just my 2 cents.


I hear where you’re coming from. I don’t use any conversion factor but I do track “indoor TSS” and “outdoor TSS” by tagging each ride (and later using the tag to filter). I use tags for other categorization as well, but this is one of the main ones.

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All outside. Base 2. Elapsed time, not moving time. This is a rest week.

Strava moving time for that week. So only 18 minutes stopped at traffic lights on 5 rides.

About 3% downtime that week.


If every ride you do is with a purpose, I don’t think there’s any difference in outdoor vs indoor. If I want to do a 3 hour Z2 endurance ride outdoor, I plan my route so it’s mostly flat, so I can stay in that zone. I can do a 3 hour ride with barely any coasting.
Physically there is no difference. Mentally I agree indoor 3 hours is a bit harder. Although I do find it easier with a nice Z2 endurance Zwift group ride.


If you go by TSS then you shouldn’t have to do any extra calculations. The lack of coasting indoors will already be factored into your TSS.

Personally, I’m just not going to worry about 3+ hour trainer rides. They aren’t much fun. I do a warmup, interval set, and it’s 90 minutes all in. Sometimes I’ll do a little extra and hit 2 hours. 3 hours of extra zone 2 - forget it.


LOL saying this to a guy that has a “Nobody Cares, Work Harder” avatar


I think the only justification for trainer time being more valued than outdoor would have to be from not coasting. So if you don’t have much coasting outside, they would be closer to 1-to-1.
The TSS takes NP, your FTP and duration, so identical TSS from a week spent inside or outside is irrelevant (assuming you train the same way).
I personally only ride up to 70mins on the trainer bc it is just too boring (relative to outside). I hit about 8-10hpw like yourself. Most of my weekly TSS is from a 4-5hr outside ride (at all costs! Will ride as low as 20degree F as long as it’s not windy).

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What I would say is that TSS is TSS. It’s based on your power output relative to your FTP, and that doesn’t change whether you’re on the road or on a trainer (assuming of course your power meter is the same and calibrated). TSS is not time dependent. Meaning accumulating 100 TSS in 1h is the same as 100 TSS that’s accumulated in 2h. The difference is in the effort. 100 TSS in an hour is threshold, whereas in 2h you’re cruising. So your 500 TSS week on the trainer is still equivalent to your 500 TSS week on the rode as far as stress load is concerned, even if your total training time differs, or distances, average speeds, etc.

What is different from road to trainer is there’s no coasting on the trainer. There’s no stop signs, lights, traffic. The lack of breaks - plus the particular trainer setup you have - may require more effort for the same duration, or more effort to achieve road speeds.

All that said, I don’t think there’s a particular multiplier that can be applied- there may be for equivalent time, but like I said earlier, TSS is TSS. For me, a 1.3h road ride at 20 mph feels about the same as a 1h trainer ride averaging 16.5. But that’s my setup, and how I feel on the trainer. Plus, doesn’t matter how aero I get on the trainer. :wink:

The more important things for me are: is this trainer ride constructive? Is this road ride enjoyable and/or constructive? Am I getting what I want out of this particular session?

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I also live in Chicago. I don’t see a lot of difference in the effectiveness of inside vs outside tss. I do think mental fatigue is a real thing, and my mind gives up before body for 10 hours on trainer. Getting out outside is good for the soul.

Doing 3 hours at Palos Sunday :slightly_smiling_face:

So true.

TSS accounts for that.

No multiple.

Im different than most people. Don’t really like dressing up to do a workout. Outside riding is for pleasure with a side of work. Inside is to do the work.

I can hit 4-5hr trainer rides regularly, if I want to. Currently building back up from being sick, only doing 3-4hr rides.

In fact, I prefer indoors for Z2 work. Outside Z2 is boring as fuck. At least I get to watch tv and not worry that a lapse in concentration due to the ridiculously boring work, would end me in a car crash and die.

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Funny … I am the exact opposite. I find indoor Z2 rides to be nightmarish. I love doing interval working inside and Z2 outside. It’s amazing how we all come at this differently…


I do intervals indoors too. :slight_smile: outdoors is for free riding. Working on things that are less tangible, pacing, attacks, form, recovery and repeated attacks. More free formed, not following a set timer. If my coach were to tell me to do intervals outside, I would ignore him completely. I can do TiZ but not doing anything formalized outside.


I only find indoor tolerable when it’s a spin class at the gym.

I cannot produce same power (above z2) inside so doing intervals indoors rise some questions for me…

Putting numbers aside, it’s about the enjoyment factor and wanting and being motivated to ride. When the weather’s bad I do 3hr rides on the turbo and don’t particular enjoy it, but needs must.

I’d take outside riding any day of week irrespective whether one is better or not from a numbers perspective.