W/kg vs System Weight

I have been reading a few threads on the TR forum about W/kg and FTP, but what I am curious about is how often as riders we actually take in to account our system weight as a total before we head out the door for our 60mile loop?

I am beginning to feel the indoor measurement at the top of my career page of weight, ftp and W/kg is just that, an indoor measurement. Something that is constantly fluctuating almost daily.

For example I might be 80kg first thing in the morning before an indoor session but buy the time I am heading out the door on Sunday I might be 82kg plus and with my fully laden bike that might equal a total system weight of 92kg.

Is power absolute when taking total system weight in to consideration? I feel that riding outdoors is just as important in that sense because it feels like a completely different stimulus.

Interested to hear thoughts, comments and criticisms.

Are you counting your bike with those extra 10kg’s?

When I go out on my long distance rides, depending on season, I carry:

1 multitool with tire levers attached
2 CO2 cartridges
1 small pump with CO2-connection
2 meal bars
Spare tube
Water bottle

All in all a weight of approx. 1kg extra. Shoes and clothing an extra 0,5-1kg depending on season.

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I would be asking when is each relevant?

Indoor W/kg - Trainerroad
Outdoor TOTAL W/kg - Possibly race prep/strategy using Best Bike Split?
Outdoor simple W/kg - Bragging rights :smile:

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I imagine that w/kg in the professional world is most useful in Grand Tour climbing stages - where Sky or Astana can set a tempo, knowing that everyone’s clothes, bikes, bottles etc weigh pretty much the same across the peloton. So the DS can just shout for them to up it to 6w/kg when they want to put the hurt on.

It’s just a number to isolate a trend which verifies training. You want to verify what you’re doing is working (physiologically) so that you can stay with the lead group or get that KOM or simply achieve a certain VAM etc…

For most it’s easier and more reliably consistent to measure W/Kg w/o the bike. If you want to calculate W/Kg with the bike and clothes just do it with exactly the same bike and clothes every time. All that really matters is consistency.


This is a very good point, in terms of tracking a physiological trend.

What is your view on the importance on being consistent with some form of outdoor riding because I feel my body aches in a different way after 2hrs outdoors vs sat on the trainer?

Is my body being stimulated in a very different way?

In my opinion yes. Depending on what trainer is used I think there are three key differences between riding on a trainer and outdoors:

  • When muscles engage and how long they stay engaged. Depends on inertia…
  • Increased muscular endurance on a trainer due to no micro breaks.
  • Reduced upper body contribution.

Obviously some riding outside is important if you compete. From sprinting, group skills to mountain/cx bike skills which are all but impossible to replicate inside. Also, just to keep sanity and have fun (for me) riding outside is a must. But, I live in an area that is mild so it’s easy. If I lived in Michigan right now I doubt I’d worry too much about getting outside and focus on the trainer. When the weather turns in the spring then I’d be outside for sure.


Not sure what you mean, my forecast looks fine today :neutral_face:


  • WHAT…Snow and sleet changing to light freezing rain. Light snow and sleet develops after 9 AM, increases in intensity by 11 AM, and then transitions to light freezing rain or freezing drizzle by early afternoon. Snow and sleet accumulation of 1 inch or less.

Scattered moderate intensity freezing rain showers are possible after 3 PM. Total ice accretion is forecast to be a tenth of an inch or less with localized periods of sleet.

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I like numbers :slight_smile:

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