No help from Bkool... Anybody knows how these zones are calculated?
I suspect that this may be a question that a lot of users have wondered about, so this explanation is intended to be generally applicable to everyone.
The zones are percentages of your FTP, and they seem to be the same percentages as those devised by
Andy Coggan. His reason for choosing these percentages can be found
here.
Bkool calculates the zones automatically, and while it is not possible to directly change your calculated FTP,
it is possible to override those zones and input your own.
On the Bkool website, click on your name and then select "Profile" from the drop-down list.
There are four tabs on the Profile page. The fourth one is "Fitness Level". Click on it.
The page gives details of your current level, and at the bottom of the page lists your current working zones for power and for pulse (or heart rate, as I usually call it).
Click on the Pencil icon (to the right of where it says POWER (or PULSE).
The maximum and minimum wattages for each zone are now visible, and can be changed to whatever figures you wish.
Don't forget to click "Save" when you've finished.
For most people, Bkool's calculation should be fine - but
@borchgrevink seems to be a special case because he hasn't done a formal FTP test on Bkool, so it doesn't base the calculations on the correct FTP.
@borchgrevink - if your last FTP value was 294 watts, I think your zones according to Coggan should be:
z1 0-162
z2 163-221
z3 222-265
z4 266-309
z5 310-353
z6 354+