rsbob 

On Zwift rides on flat, I can regularly do 25 MPH, but IRL doing 25 on the flats with wind resistance is completely another thing. I even hit 55 MPH on one Zwift downhill. IRL very doubtful especially around 90 degree curves.

tempocyclist

Zwift physics are super flattering. Mostly butter smooth roads, no wind, perfect aero, no corner braking. It's especially true if drafting (or even just the busy "conga line" streets of Richmond flat route).

It's a video game, I doubt it would be as popular if it made you slower than real life! 😅

Time spend on the trainer / spin bike should be measured in hours and output. Distance is meaningless (technically, the same could even be argued for outside).

PeteHski

Of the various bike sim apps, I think RGT is the only one that simulates braking for sharp corners. The rest, like Zwift, just totally ignore cornering speed limitations. It doesn't really matter, but it's pretty easy to implement.

PeteHski

Exactly. Mileage is not a very good indicator of workload in either the virtual or real worlds. It's just something people tend to log i.e. "Last season I did X miles". It says nothing about the riding terrain or workload. If you use TSS to log your workload, then mileage/speed is irrelevant anyway.

delbiker1 

The effort of pedaling on an indoor trainer/bicycle is just not the same as riding in the outdoors environment. Just so many factors involved. Trying to compare the two speed wise does not work so well. Measuring the intensity and wattage output would likely work better for comparison. I am not a fan of pedaling indoors. When I did it a few winters ago, I was doing intervals to break up the monotony. Also, for me, doing intervals indoor was much easier to keep the time and pace of the intervals where you want them, ergo, better for training.

livedarklions

When you get right down to it, the only good reason for logging your "miles" in that manner is motivational, you're doing it for yourself. If, for whatever reason, you find it easier to get yourself on the trainer by considering those miles "real", then go for it, and calibrate the miles in whatever manner you're most comfortable with and enthusiastic about.

Like everyone has pretty much pointed out, miles aren't really a good measure of effort in any form. I keep track of my real world miles because I find "I'm going to ride 125 miles today" a lot more motivating than "I'm going to spend 13 minutes in the hoozits zone" or whatever new-fangled metric it is the kids are chasing today.

BCDrums

I prefer to use miles. I understand that miles on a stationary bike are not directly translatable to road miles, but it allows me to compile a year-round effort in one metric. I accept its limitations.

The effort to create the pretend miles is not pretend. I use the imaginary miles to reflect the effort. I could use a power meter, heart rate monitor, and timer (all good suggestions above) and I'd get a more scientific metric, but I'm not in training, I'm in exercise. I don't need the precision.

Your screen name always gives me a laugh. Thank you.

LDL makes a pretty good summary for me here. My goal in riding is enjoyment, and to remain fit (and vertical!) for quality of life. So I collect miles, and at the end of the year I feel good about my total.

Thanks all!

PeteHski

In that case I would simply calibrate your trainer speed sensor so it typically gives a similar average speed to what you achieve outdoors for a similar effort. Even if it's not quite equivalent to outdoors, you will still consistently log virtual "miles" on the trainer. So you will be able to see whether you did more or less trainer miles over a period of time along with a rough estimate of your equivalent overall mileage from adding indoor and outdoor mileage.

As you rightly say, the effort required to log pretend trainer miles is very much real!

burnthesheep

Yeah, the "infinite draft" thing is a bit silly. I sometimes will "world hack" to be in a really quiet more lonely area. Or jump on Rouvy instead.

Also, people have argued it to the ground trying to prove otherwise.........but Zwift is super super flattering for aero of what I would deem more average riders. You can infer from that what you want. But, Zwift flatters folks that wouldn't be so aero efficient in real life.

BCDrums

This, finally, is what I have done. Thanks.

msu2001la

Whenever I'm really struggling with my speed on the trainer I just turn the fan around and... instant tailwind.

bikebikebike

Small wheel circumferences are not well represented on the charts and may have larger variances if not calibrated.
there are speed/cadence charts to get a quick check
If all your numbers line up, good. If not it's a project to calibrate.

lots of bad data out there
Get data that is meaningfully comparable for you, unless you like math for sport

Mojo31

Don’t fool yourself, the average speed of any stationary bike will be zero mph.

BCDrums

Har!

ofajen

Perhaps more disturbing is that the average velocity for many outdoor bikes is also zero.

Otto

3alarmer 

.
...I'm thinking that as your Zwift speed approaches the velocity of light, there needs to be some compensation for time distortion due to relativity. Otherwise you might end up at your destination younger than when you started out. nttawwt