Tacx Flow 1680 Trainer
- Thread starter 82zman
- Start date
I don't have the Flow but have their Fortius trainer and really like it. I use the catalyst mode for power based training programs 4 nights a week and periodically use the real life vids if the weather is too bad to go outside, and between the two there's plenty of variety. I have never tried to race online or use the VR mode.82zman said:
Perhaps Tacx has improved the Flow but while my four-year-old model is consistent and can be adjusted to be accurate in power-measuring mode, it's pretty much useless in power-controlling ("ergo") mode. The head unit does an inadequate job of controlling the load so power isn't at all independent of wheel speed, and the percent error can be huge.82zman said:
I can only add to the previous post. I have a 3 year old Flow and its a PITA 
when used in ergo mode. It sometimes alternates from breaking you down with all its power and after the next adjustment loosens up to almost zero brake power .
When used in slope mode it works just fine. You can change gearing and or cadence and it shows you the appropriate power readings . I've compared it to my ergomo and it's consistent enough to be called a valuable tool for power training.
FWIW the Flow is a good base for upgrading to VR (I-Magic). You simply buy a new interface and then you can use VR, ergvideo and all that. BTW that's how I did it.
bigwillie013
when used in ergo mode. It sometimes alternates from breaking you down with all its power and after the next adjustment loosens up to almost zero brake power .When used in slope mode it works just fine. You can change gearing and or cadence and it shows you the appropriate power readings
. I've compared it to my ergomo and it's consistent enough to be called a valuable tool for power training. FWIW the Flow is a good base for upgrading to VR (I-Magic). You simply buy a new interface and then you can use VR, ergvideo and all that. BTW that's how I did it.
bigwillie013
Not disagreeing with previous posters, but ergo mode can work fine/OK as long as you don't expect too much of it.
What I do, is spin up to my target watts in standard mode, then switch across to ergo. That way the ergo only has to hold a fixed power, rather than follow variable output/generated power .. which as above, gets pretty dicey.
On the other hand, I find it pretty over-optimistic in the power readings. If I could transfer the power the Flow says I'm putting out onto the road, I'd die a happy man! From what I can see, it's reading 30-40 watts over.
The other thing to bear in mind is that the Flow (like all trainers I guess) is highly dependant on tyres and tyre pressure. Simply changing from Conti GP3000's to GP4000s's resulting in a change of about 20% (down) in all the readings I was getting - clearly the GP4000s's have much less slip.
Having said all that though .. the Flow is great! It has enabled me to work with power in my training, and reap the benefits. If you use the figures in a relative rather than an absolute fashion, then it's no problem.
B
What I do, is spin up to my target watts in standard mode, then switch across to ergo. That way the ergo only has to hold a fixed power, rather than follow variable output/generated power .. which as above, gets pretty dicey.
On the other hand, I find it pretty over-optimistic in the power readings. If I could transfer the power the Flow says I'm putting out onto the road, I'd die a happy man! From what I can see, it's reading 30-40 watts over.
The other thing to bear in mind is that the Flow (like all trainers I guess) is highly dependant on tyres and tyre pressure. Simply changing from Conti GP3000's to GP4000s's resulting in a change of about 20% (down) in all the readings I was getting - clearly the GP4000s's have much less slip.
Having said all that though .. the Flow is great! It has enabled me to work with power in my training, and reap the benefits. If you use the figures in a relative rather than an absolute fashion, then it's no problem.
B
RChung said:
As I said, the displayed watts are not accurate compared to actual power. My "fine" only refers to ergo mode, and my point was that ergo mode can do what it's supposed to if you treat it kindly and don't ask it too take total control .. or much control at all for that matter.
Riding at a steady state I can switch in and out of manual and ergo modes with no real change in what's going on .. same speed/cadence/effort/displayed watts.
If you use the watts displayed as relational rather than actual watts, I've found it a great training tool. If you want to work to real watts and test yourself re real watts, forget it.
B
I tested it against my ergomo and the flow/I-Magic always showed significant higher readings. I had it corrected with the settings and since then it's accurate not only on relational but actual Watts.RChung said:
I'm sorry, perhaps I wasn't being clear: I meant, have you checked your Flow in ergo mode against a calibrated power meter? Because it wasn't fine/OK at all. Here's a plot of what I found:bing181 said:
If the ergo mode had been operating well, those groups of dots would be horizontal since the load generator should adjust load in response to changing roller speed. As you may be able to see, those groups aren't horizontal, and the error can be huge (a dot above the zero line means that the Flow's watt setting in ergo mode was higher than true watts as measured by a Power Tap that had been validated with a static calibration check).
Conversely, in power-measuring mode, the Flow was pretty accurate once I found the correct combination of calibration number and scale factor.
You can adjust both the scale factor and the roller pressure, though since different tires have different Crr characteristics I suspect those settings will vary from tire to tire. For example, with my tires at a set pressure, I can get pretty good agreement between the Flow and my PT in the neighborhood of my FTP if I set the rolldown calibration to +2 and set the scale factor to 89. There's also a line voltage adjustment but it only moves the readings up and down a tiny bit.bing181 said:
I've changed the calibration scale to 92 and that made it happen! As I always use the same tire (blue Tacx Indoor trainer tire) and as I always check the pressure in the tire and as the roller pressure never gets changed the setting doesn't have to altered anymore. Maybe unique to my setting but I like it that way and won't complainbing181 said:
Cheers,
bigwillie013
