Difference in distance

Compared my (Carson) data with a friends ride. Moving time/avg power/avg speed/calories/avg heart rate are similar (I do not know his FTP), but distance, mine is double his… (20mi vs 10mi). He does have a smart trainer & I do not.

just curious if I’m set up correctly.

Both your distances were zero! Don’t mean to be flippant but distance means absolutely nothing on a trainer. Can make it whatever you want by increasing/decreasing gearing and/or tyre pressure and/or roller pressure.

Literally means nothing - so much so I set distance for all my trainer roads to be zero!

The distance reported will be equivalent to the circumference of your rear tire multiplied by the number of times it spun around, it’s as simple as that. He probably stuck his bike in a low gear and let the trainer modulate the resistance to hit power targets, so it looked like he was traveling ~10mph. The resistance on your trainer is designed to closely emulate outdoor conditions, meaning you couldn’t sit in a low gear the whole time, and you had to shift gears to hit power targets. Your distance will always be a rough approximation of how far you would have traveled outside on flat pavement with the same effort (because that is what the power curve of your trainer is likely trying to emulate), whereas his will always look like he rode 10mph if his cadence stays roughly the same on each ride, no matter how many watts he pushes. The only thing that will affect his distance will be changes in cadence.

TL;DR ignore distance on indoor trainer rides, they mean nothing

EDIT: Your distance will at least vary proportionally to your effort, so it doesn’t mean nothing, but your friend’s distance is not worth looking at


I get what your saying, but that’s a bit of an over statement. Following that logic outdoor speed and distance is also meaningless if you think about it. If you are descending with a tailwind, ascending with a headwind or on a MTB through single track then distance is all meaningless. Not really though. Distance is relative, not necessarily meaningless.

Is that not the same outdoors?

To answer the question, the difference arises from the measurement methods.

You are likely using a speed sensor, and that will report as the source. It’s the simple number of revolutions times the circumference you have set in TR.

Your friend has a similar deal, as his smart trainer reports speed based on his rear axle revolutions times the circumference entered in the trainer and/or TR app.

The difference between the two, assuming he is using ERG, may come from the fact that he can do the workout and hit the power targets at a range of gearing selections.

Erg allows you to use high, middle or low gearing. As such the “ride distance” may vary from one setting to the next, even on his, let alone compared to yours.

Does that make sense?

A fair question, and one I originally asked when I started as well. If you are using a direct drive trainer (Kickr), speed will be affected by which gear you are in even if you aren’t shifting. My middle ring on my rear cassette gets me about 23 mph when I’m in my large ring up front, but drops significantly to 15 or 16 if I do small ring up front.

Really - it doesn’t matter in the long run, because distance is a useless indoor metric, BUT you can make some adjustments to find a speed that you think aligns with your fitness if you choose.

Distance not same outdoors as if go slower then will travel less distance for same time. Also most rides end up being a loop so generally hills and wind cancel out to a certain extent. But yes - with more use of PM…Can argue distance is less relevant than pre power era even outdoors.