Today’s video is about how to use VAM to approximate power without a power meter.

Link to spreadsheet here: https://docs.google.com/spreadsheets/d/1i7xmd-ZzGYoMrZ3KTMeJbmW7RmoxNrtKrZmE6t5Q8XE/edit?usp=sharing some more information on the physics here: http://theclimbingcyclist.com/gradients-and-cycling-how-much-harder-are-steeper-climbs/

The problem I have is I’m heading to italy shortly, but i’m hiring a bike without a power meter. I’m terrible at pacing myself, but have learnt to stare at stem and sit on 3.5 to 4w/kg pretty comfortably. But how to do this up those HC climbs in Italy without a power meter?

Similarly, what if youre out and about and your power meter runs flat or has a fault?

For those (first world problems), let’s go old school and get reacquainted with VAM.

Firstly what is VAM?

Back before power meters were cheap enough to put on most bikes, VAM was invented by the sports scientist, Dr Ferrari, and for all his sins to cycling, he was pretty good at measuring cycling performance… most probably to see if the drugs were working.

VAM is italian for velocità ascensionale media, loosely translated in English to mean "average ascent speed" in Vertical Ascended Metres per hour. It is a measure of how fast you are ascending a hill.

As you can see, VAM is the a function of watts/kg and gradient. So if I know the gradient, and what my threshold power is, I know what VAM I should hold on that climb.

Using the 2 Standard Deviations rule, it means I’m 95% confident of using VAM to estimate W/kg to within +/- 8.22%

It’s not perfect, but certainly much better than nothing. And critically, focussing on the 800-1100 VAM (~3.5-4.0 w/kg) it seems to be much closer

So how do I set this up?

Well, using the wahoo app, i connect my wahoo device and then setup the screens. I like the climbing screen so it shows profile if you have a route or segment loaded. I then add VAM and gradient to the display.

Using the table, I know that at 5% and 1000 VAM is 4 w/kg. If I want to keep that same power, for every 1% increase I need to add 40VAM to keep the same power, so at 8% I need to be at 1120VAM. Or at 3%, I need to be at 880VAM.

I hope that helps to explain how to use VAM as a substitute for a power meter.

Let me know your thoughts in the comments below and hit subscribe if you found this interesting.

Cheers
Derek