gbrown
Geoff on Bkool
- Location
- South Somerset
my 2p worth...
As @bridgy says, power in bkool is calculated from speed, presuming a level of resistance from the trainer that is only an estimate, and is neither well calibrated nor confirmed. It merely presumes the complex physics involved in generating the resistance will be spot on at all times and doesn't measure the actual resistance/power being produced to confirm it!
There is no power meter to measure actual power, nor is the resistance accurately calibrated across the entire range of variables (an almost impossible task)!
It is certain that actual resistance will vary from presumed resistance depending on the speed and acceleration of the roller, and is likely to be higher than expected at one speed and lower than expected at another. Therefore riding at a slightly different speed may cause the estimated power to be either too high or too low, with no detectable logic for when it will be one or the other, apart from the obvious one that once the resistance is maxed out, power will read higher than actual.
Just changing gear, or pulsing your speed slightly can change the physics of the magnetic eddy current braking and cause wide tolerances to change the variation of actual to calculated power.
It is entirely possible that one rider could produce a higher FTP in bkool than another, but be lower in another test.
FTP in bkool is nothing more than a wild stab in the dark, especially on a steep incline! It's just a bit of fun and helps motivation. A bit like weighing yourself on one of those body fat scales, it is so rough and ready that it's only value is in showing a general trend over a long period of time, if all factors remain the same.
Getting your FTP from 30+ minutes rides on bkool is pretty much pointless, as each such ride will vary so widely!
If you want to judge your fitness over a period of time on bkool, I would suggest the best thing is to take official 20 minute FTP tests (the bkool 2% gradient ones) on a regular basis, as near as possible to the same conditions (time of day, rested-ness, warmed-up, gearing/tyre pressure, etc. and effort), then a sustained improvement in average power over time should show your training is working.
If you want a better estimate of FTP, you need properly calibrated equipment, with a proper power meter at the minimum.
However, even then FTP varies depending on your mood, health, rested-ness, warm up, effort, motivation, temperature, nutrition, etc. so it is always a rough guide to performance.
Geoff
As @bridgy says, power in bkool is calculated from speed, presuming a level of resistance from the trainer that is only an estimate, and is neither well calibrated nor confirmed. It merely presumes the complex physics involved in generating the resistance will be spot on at all times and doesn't measure the actual resistance/power being produced to confirm it!
There is no power meter to measure actual power, nor is the resistance accurately calibrated across the entire range of variables (an almost impossible task)!
It is certain that actual resistance will vary from presumed resistance depending on the speed and acceleration of the roller, and is likely to be higher than expected at one speed and lower than expected at another. Therefore riding at a slightly different speed may cause the estimated power to be either too high or too low, with no detectable logic for when it will be one or the other, apart from the obvious one that once the resistance is maxed out, power will read higher than actual.
Just changing gear, or pulsing your speed slightly can change the physics of the magnetic eddy current braking and cause wide tolerances to change the variation of actual to calculated power.
It is entirely possible that one rider could produce a higher FTP in bkool than another, but be lower in another test.
FTP in bkool is nothing more than a wild stab in the dark, especially on a steep incline! It's just a bit of fun and helps motivation. A bit like weighing yourself on one of those body fat scales, it is so rough and ready that it's only value is in showing a general trend over a long period of time, if all factors remain the same.
Getting your FTP from 30+ minutes rides on bkool is pretty much pointless, as each such ride will vary so widely!
If you want to judge your fitness over a period of time on bkool, I would suggest the best thing is to take official 20 minute FTP tests (the bkool 2% gradient ones) on a regular basis, as near as possible to the same conditions (time of day, rested-ness, warmed-up, gearing/tyre pressure, etc. and effort), then a sustained improvement in average power over time should show your training is working.
If you want a better estimate of FTP, you need properly calibrated equipment, with a proper power meter at the minimum.
However, even then FTP varies depending on your mood, health, rested-ness, warm up, effort, motivation, temperature, nutrition, etc. so it is always a rough guide to performance.
Geoff
