Calibrating a Tacx Flow Turbo Trainer
My Tacx Flow Turbo Trainer has a built in calibration device allowing it to ensure that workouts you do on it are consistent despite changes to things such as tyre pressure, contact pressure, bike you use etc. Any change to such things would make a difference to the efficiency and could therefore adjust the effort needed for a particular workout.
The calibration system is easy to use. Press a few buttons on the computer, then pedal up to a certain speed at which point it tells you to stop pedalling and it then measures the amount of time it takes for the wheel to come to a halt. From this, the turbo trainer can work out what braking resistance it needs to use so that it remains calibrated from session to session.
It is recommended that you do this from time to time just to make sure the machine is still calibrated correctly and you should do it if you change things such as a tyre, tyre pressure or anything else on the bike. I’ve done it a few times since having the turbo trainer and the calibration result has always been ‘+2’. As I understand it this means the braking resistance is slightly higher than a factory default of 0.
The bike I use on the turbo trainer is quite nice, everything works really well on it, it is smooth and has an amazing rear hub and I keep the tyre pressure high so that always made sense to me as the turbo trainer needed to up the resistance a little to compensate for the efficiency of the bike. However, the bike is also 20 years old and the tubular tyres on it have been on there for 20 years. Most of that time it has been sat in a shed and the years had taken their toll on the tyres. The cracks and splits in the rubber finally succumbed to 500 miles abuse on a turbo trainer so I replaced the rear one over the weekend.
Cue a re-calibration of the Tacx Flow. I re-calibrated today with the new rear tyre and this time got a reading of ‘+1’. I left it at that as I assume that means it will now give me a braking resistance that will allow me to replicate workouts I was doing before despite the new tyre.
The only way I could test it was to do a known workout and see how it compared. I therefore did my normal 1 minute interval session with the hard efforts at 350 Watts. Trouble was I was planning on upping this to 360 Watts next week as it was now beginning to feel quite comfortable, on top if which I was well rested today and felt quite good.
The workout did feel a little easier than usual with my heart rate reaching around 162 on the efforts rather than 166, but I now don’t know if this is due to the slighty lower braking resistance following the re-calibration or the fact that I should have been in good form and I’m improving.
I guess I’ll have to see how it pans out over the next few sessions… It does of course mean that I’m still on target and can increase the power output on the hard efforts to 360 Watts next week as planned.