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🤘
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.
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.
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).
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.
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?
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.
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…
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.
