chaadster

Physiologically, I have no idea if it’s easier to make power indoor or out, but I’ve never felt there was much of a difference. It’s hard to tell, though, because I mostly do structured rides indoor but never do them outdoor, so I don’t have apples-to-apples data. Looking at “JRA” (just riding around) on the trainer compared to JRA outside, that’s tricky to compare as well, for two main reasons: 1) I usually group ride outside, and 2) being indoor allows me to ride harder over shorter periods without fear of being dropped or running the tank to empty. I think the variability in my ride data, in terms of power peaks and averages reflects that, with higher one hour averages, generally, on the trainer, higher shorrt period peaks on the road.

Further complicating comparison for me is that I’ve been riding a PowerTap stationary bike for ~13 years at the studio, and have had a couple of different turbos at home, including the Kickr I’ve got now and have been using since ‘17, I think. Those two are extremely different— the Powertap bikes use dial adjust friction pads on heavy freewheels— and engender different types of indoor rides, particularly notably for resistance changes in Zwift with Kickr. They’re both hub power meters, and outdoor I use pedal power, which should read a little higher accounting for drivetrain losses; I’ve had Powertap wheels and run my Assioma pedals on the Kickr, and don’t see a lot of difference there either.

It’s just different kinds of riding, each with diverse goals and opportunities, so I find it hard to compare, even though, broadly, both power and PE align for me on road and trainer. When I’m fresh and good, what feels like 150w, 250w, or 400w at the legs usually is on the bike and trainer both. When I’m tired, what usually feels like 400w is actually 150w on both bike and trainer, too! 😂

PeteHski

I think so too. For me, the key point is that indoor riding is far more productive than not riding at all, which is what I often did before I had an indoor trainer. Similarly, smart trainers have been much more productive for me than dumb trainers simply because I use them far more often. The physical differences probably don't really matter much.

Jughed

Same. I used the bike power meter when on my dumb trainer. I could do the same efforts on each type of trainer - but I didn't.

To date, mileage with my smart trainer and zwift is well over 2x that of my typical winter mileage on my dumb trainer. Could be close to 3x... and I'm only 1/2 way thru winter.

The dumb trainer in mind numbing. I used to dread riding on it - hated every minute of it. I actually look forward to zwift rides and challenges.

canklecat

My old Cycleops dumb trainer definitely feels harder and the wheel sensor based speed doesn't correspond with the effort. I'm laboring to maintain 15 mph on the trainer, which would be closer to 18 mph on the road. Same with older air fan type bike trainers -- the resistance on those always felt harder that road riding for the same speed.

But I've never used a contemporary smart trainer or one that doesn't depend on a wheel with tire. No idea about the "feels like" gauge on those.

And all of it is easier than running. I'm needing to take a few weeks off from running to let a strained hip and quad heal. Running was actually keeping me in reasonably decent shape for cycling even when I rode only once or twice a month, whereas cycling alone never prepared me for running.

Sierra_rider

In my case, the indoor activity is likely more productive than if I spent the same duration outside. The reason being the local terrain...I'm up in the mountains and there are plenty of downhills that you can't pedal down with any meaningful wattage, lots of coasting. I try to "stay on the gas" and keep the pedals spinning, but even a difficult local outdoor ride often has nearly 1/2 the ride consisting consisting of below zone 2 wattage...and steep enough uphills that force me out of a low-intensity effort. Whereas on today's virtual ride, I was able to average 260 watts for the 2 hours and have a normalized power that matched it, all zone 2.

The caveat to all this, is the amount of time I'm able to spend on the trainer. 2 hours is about my upper limit on the trainer. Meanwhile, I really enjoy spending 6+ hours out on a hilly ride. If I stuck to the trainer exclusively for training rides, I wouldn't get nearly the weekly volume that I do now.

chaadster

Dang, that’s impressive! So like a 400w FTP?! Kudos!

Sierra_rider

Thanks, but my FTP is only around 350 watts...I'd be crushing it if I could get it up near 400. I'm exactly a lightweight either, around 180lbs, so a 4.2/kg FTP. That's not to say that I'm not proud of what I've been able to accomplish. I took some time off from riding in 2022, and I was only around 3 w/kg about a year ago. My power profile has traditionally been that of a sprinter, but I've been targeting some longer XC mtb and gravel races, so I'm "reinventing" myself to a certain extent.

chaadster

Strong riding! It's great to hear that you've had success like that! Keep on rockin'!

PeteHski

Speed on the trainer is immaterial. The question is whether or not you can make the same power. If your wheel speed is 15 mph on the trainer and 18 mph on the road, that just tells you that the resistance on your trainer is higher. Do you make 18 mph on the road if there is a strong headwind or an uphill gradient? It amounts to the same thing i.e. increased resistance. But it doesn't say anything about your ability to hold the same power.

Smart trainers are able to provide a wide range of resistance to simulate different road conditions and gradients. The virtual speed generated is normally based on power output and the physics model in whatever App you are using. The power and resistance is what really matters to the rider. Speed is just a rough guide to how fast you might be able to ride outdoors in the same conditions.

zacster

I've always found the trainer watts to feel harder than outdoor, and I proved it to myself today on my first outdoor ride of the season. I was able to easily hold over 200w outdoors, even hitting 300 and holding it for a bit. On a trainer I can't hold 200 for very long at all. It all felt so easy outside. I've also lost weight, 25 pounds at this point, and that made uphill easier. My HR was also up higher than I get it on the trainer as I definitely am working harder outside but my legs don't feel it. If my HR got that high on the trainer I'd just back off but it didn't feel that way today. But the ride also pointed out a few weaknesses, so I have to work on those. While uphill was easier, I used to be able to climb the hill in the park at speed, but I definitely slowed down some. Maybe I need to do more climbing at higher output. I did a Haleakala climb in Rouvy last week, but that's a slow slog. Or maybe more interval training. I mostly just free ride in Zwift. Maybe intervals but NOT in ERG mode as that just grinds me down.

Today was an exception though with the weather, 65 and sunny in NYC. It is supposed to rain the rest of the week so I'll be back on the trainer.

Hermes

I owe RChung some files and I have not sent them - to busy riding but more like have to find the files and download which is a weak excuse.

Jughed

Quoting myself.

First 3 week block of intervals - mostly 10/15/20 min threshold sessions were done indoors. Zero issues completing any of the sessions and my power was relatively high.

After a rest week I just finished my first week of interval sessions outdoors.

Different bike, different power meter - but the results were way different. Could have been residual fatigue from the first block - but my power was lower and I was unable to complete the first 2x10 min session. I did complete the 3x10 min session, at a lower power level and a much higher RPE than indoors.

Indoors I'm hovering around 300w for 10min and not dead at the end, outdoors I'm 270-280 and blasted at the end - 270-280+ was my indoor 20 min power.

As I sit here right now, I'm destroyed after last evenings 3x10's... destroyed.

Next week will be a 2x20 and I'm already dreading it.

This could be a factor. Indoors on Zwift I can keep the watts in a tight range - 5w+/-. Outdoors on the flat area that I do intervals (I don't have any long hills here), power is all over the place. My MUP varies 5' up and down - very gradual, hard to notice. Power drops off on a down slope then I surge to bring it back up.

I don't think the power really matters. The outdoor rides seem to kick my butt harder and probably have better long term benefits.

PeteHski

How does your normalised power compare indoor vs outdoor? I find np correlates closer than average power because outdoor power is much more variable. Although I rarely do outdoor fixed power intervals. If I compare indoor vs outdoor endurance rides I always see a lower average power outdoor, but normalised power is a lot closer.

Jughed

NP is similar...