For the past few years I’ve been using a mid priced (£150 ish) Tacx turbo trainer.

Thinking about upgrading to the Flow as seems to be some good deals around at the moment but is the upgrade worthwhile? Will I gain much from being able to use the Power facility to train with?

Any comments appreciated.

Training with power is very effective if you do it properly, well worth doing if you’re serious about your training.

May be worth looking at putting the money towards a power metre (e.g. Stages or PowerTap) instead that you could use on and off the turbo. Worth having a look at TrainerRoad too, whether you use a proper power metre or it’s virtual power feature.

Don’t bother. The power reading on a Flow isn’t precise within a session, never mind between them.
Speed isn’t an ideal measurement on a turbo due to pressure/temperature differences but it’s a damn sight cheaper than a Flow and probably more accurate and precise.

Disagree with a point in the last post. Whilst it is nowhere near as reliable as a genuine power meter as long as you keep the pressure in the tyres consistent and recalibrate it every session ( I recalibrate it in between sessions too) then it is a good training tool. It is inaccurate but as long as you see your numbers rising over the course of 2/3months then that means you are getting fitter. If I had the money for a power meter then I would buy one of those and not the Tacx but for those on a tighter budget the Tacx can help. I bought mine second hand off here for £100.

Matt Lewis

Does it really measure power or just do a calculation based on wheel speed? Can’t tell from the website. If it’s the latter you’d probably be better off going for trainerroad and an ant+ speed sensor.

I bought one thinking that I could set up a bike on it permanently as a fit and forget job. I ran it alongside a Powertap to get a handle on any errors and factors I would have to apply to the data but it was a waste of time.
Same tyre pressure, same warmup every time. Non-linear errors across the wattage range that were themselves unrepeatable within a session. Different level of error the next time. And the next. Eventually gave up, sold it, and put the money toward another Powertap.

Mine may have been a dud, quite happy to accept that.

And dare I say that the prices of PowerTap and Stages are getting quite reasonable these days (as far as power metres go anyway.) Had a powertap for about three years now and it’s been brilliant, though mostly it stays on the turbo bike.

You didn’t sell it for a hundred quid did you?! It’s not perfect, I accept that and I’d love a real one but the numbers on mine seem to be consistent but nowhere as realistic as they would be on the road. I think that my Tacx flatters me a lot! But when our second child turned up in deep, darkest January I relied on the Tacx and had a strict training plan then a friend drew up for me based on the Tacx and it helped me up my game. The power I can push out for 2x20mins has definitely gone up but I find that it is more accurate (not much more mind) in the resistance setting. When I set it a certain power resistanc e then when it seems to go all over the place. That makes no sense that last bit. sorry, it’s garbled!

Matt

I have a flow that I don’t use, DM me if you’d like to buy it off me.

BTW I think it’s an effective training tool if you like to train by numbers, I commute daily now so not have the need any more.

My flow on slope 3 is always within 10% of my quarq power meter
It’s also surprisingly close to trainer road virtual power as well.

I doubt it is accurate enough for a pro but I like mine and it seems consistent across sessions – ie when I do tapata and go all out for example

Is it worth not sure depends what you want

For the amount of time I use it probably not for serious training probably

The power reading on a Flow isn’t precise within a session

Mine’s 11 years old and I find that. However, the way it fluctuates is reasonably predictable, and hasn’t changed over the years, so if you factor that in it’s not too bad.

But, if you do a ‘coast down test’ at the start of the session on your current trainer, set it to be the same every time, and use speed as proxy for power, you get the same result. You have to do a ‘calibration’ every time you use a Flow, which is just a coast down test where it counts the seconds for you…

I doubt it is accurate enough for a pro

I’d bet that powertaps etc are nothing like as accurate as folk think. There’s a difference between resolution and accuracy that fools people too often. I’ve done 30+ years in Test Equipment and it still amazes me how people believe what they read on a screen without thinking about just how that number was generated.

afaik – Tacx use the same flywheel & magnet combination over most of its range.
I calibrated my brother’s Tacx the other night with a powertap – on setting 6 (and me = 70Kgs).
Anybody who wants the calibration curve – just shout.

What do you calibrate the Powertap with ?

Easy to check a PT is working properly by hanging a known mass off the end of the crank and looking at the torque reading. I’ve got three, all read within 1% of each other.
Obviously there could be errors when actually riding rather than static.

I calibrated my brother’s Tacx the other night with a powertap – on setting 6 (and me = 70Kgs).
Anybody who wants the calibration curve – just shout.

Good man if you got it within a reasonable error. I’d suggest trying again and seeing if the curves match. Mine really was all over the place.

You didn’t sell it for a hundred quid did you?!

🙂 Nah, somehow when I sold it there was a shortage of Flows (maybe they’d altered them to get them to work properly 😆 ) so I managed to sell it for more than what I paid. Wasn’t displeased in the slightest!

What do you calibrate the Powertap with ?

Its just been re-calibrated by paligap? So should be fine?

Didn’t know the curves varied on magnetic turbos so could try see again.

HTTP404,

Any chance that I could have/see one of these calibration curves, please?

Thanks,

Matt

Matt.

https://docs.google.com/file/d/0B-5pfs3qzPX6OFMxX1Bka3I1X00/edit?usp=sharing

The equations on the graph worksheets are what you really need.

Thanks for comments.

I might give Trainer Road a go first of all as have a garmin plus a USB so only a $10 outlay initially.

When doing a trainer road workout, how do you know what resistance to be in?

If your trainer has multiple resistance settings then I think on TrainerRoad there will be multiple options for your trainer for different resistance settings (or there may be just one with a stated resistance setting.)

Golden Cheetah is also very good and its *FREE*.
It doesn’t support as many trainers in terms of *virtual* power but it will give you a consistent workout if you pick one of the available ones.
Free workouts are also downloadable. And the analysis options are very detailed.

Been tempted to have a look at Golden Cheetah, though more as a replacement for TrainingPeaks. Was reading an article the other day about the AeroLab feature which sounded intriguing.

TrainerRoad is really good overlaying a bar along the bottom of the screen with some video playing. Does Golden Cheetah do something similar?

Golden Cheetah can also do the video thing.
But it is not as slick as the TrainerRoad offering.
Trainerroad beeps as you approach a change in output and stop/starts when pedalling stops/starts. GC doesn’t have this.

You can download workouts profiles for free though. And these are synched with your FTP for target power.
Or create your own one really easily.

The post ride analysis is very good. Far more detail than TrainerRoad.
Threshold powers over various intervals are calculated and graphed.
Quadrant analysis, Cadence analysis … the list is endless.
And the ability to export/import to spreadsheet is very powerful too.

I couldn’t live without the beeping as I’m usually watching something on the telly (or have head down and eyes closed in pain!) and not paying attention to the wiggly line.

TrainerRoad could get better at the whole analysis thing though, but I guess that’s not what it’s about. It’s added a weekly TSS view thing, but only includes activities you’ve done in TrainerRoad so is pretty useless if you do a mix of riding on the turbo and outdoors. I load it all into TrainingPeaks at the moment which does far more analysis than I have time to digest! Sounds like Golden Cheetah does quite a bit of both though, and for free.

fwiw – I think it would be easy to encode a synched “beep” file to play alongside your workout (using the internal GC video player) with an application like Audacity. Haven’t done it myself yet but will do.