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I am getting frustrated with zwift and my apparent lack of power. I have a Tacx Blue matic T2650 trainer and am using a 9spd mtb on it, I have entered the information on to zwift (height,weight,age,tyre size etc) and the zwift set-up info says to set trainer to resistance level 3. i have changed the gearing on the mtb slightly (it is 9 speed with 11-32 cassette and 48t ring and 26x1.5 wheel). Last night I did the wringer workout which features 12x30 second efforts. Zwift was asking for 540w at each of these efforts, I was turning 140 to 160 cadence but only managing max 380w. This seems to happen on all the workouts that require intervals at high output. My legs will not spin faster than 160 and when comparing like for like with a friend of mine, he appears to be generating 700w at 120rpm at the same road speed as me on a flat section! Does anyone know if there is anything I can do to get nearer to what zwift says I should be doing and what I am actually achieving? I am 105kg and have strong legs so feel I am generating more power than zwift is suggesting so am getting frustrated.
The only simple answer is what we've done in the past, get a mate to come over with a bike and a known calibration/power.
We had 2 mates come over, one with a Garmin meter and one with a Stages i think it was. We then saw that the turbo i was using was 20% down on power... I then spent £500 on a Kickr Snap that afternoon, a little drastic i admit 🙂
The other time we did the same and then went through turbo after turbo on the list and got the one that closest matched the actual power meters figures, it's not his actual turbo on the list, but the power curve is as close as we can get to accurate.
Without a power meter or a smart turbo, the figures mean very little other than for your own goal of beating your own speeds/times.
My legs will not spin faster than 160 and when comparing like for like with a friend of mine, he appears to be generating 700w at 120rpm at the same road speed as me on a flat section!
Why on earth are you spinning at 160rpm?! 😯
Beyond that, what weeksy says
😆My legs will not spin faster than 160
Without a power meter or a smart turbo, the figures mean very little other than for your own goal of beating your own speeds/times.
This. Its generally stated that a turbo set up can be, but is not necessarily about 20/30% out vs outdoors even with a smart PM due to a number of reasons.
Why on earth are you spinning at 160rpm?!
It was asking for more power, the only way the power increased was to increase cadence, I was flat out at 160 and still 30%+ down on power!!
I didn't know that was actually even possible ! I've not seen more than 120. That's 700-800w in my top gear
I didn't know that was actually even possible !
It isn't for very long 😯
2 minutes or so........ (160rpm, not 700W)
What wheel size are you using? 26" would result in an 'easier' top gear wouldn't it?
And a resistance of 3 seems a bit low.
Before I got my Flow Smart, I was using an old Tacx Sirius set to a resistance of 4 and when I was really churning away I was running out of resistance to push against....
I think the calibration within Zwift assumes a 700c wheel with a 23c tyre on it.....
i think i would dislocate my hips if I spun at 160rpm 😆
Unless you're Chris Hoy, you're unlikely to produce peak-power at such high cadences - more 90-100 rpm is more reasonable. As said, some trainers can have high variations of +/-20% in terms of their readings and best to try out something that's been calibrated to give you a 'base' level - I regularly use a Wattbike and it took me a while to get used to 'real' figures rather than what some fancy software algorithm is calculating. FWIW 160rpm is reasonably quick, but it all gets a bit blurry above 220rpm. I once did an hour of 160rpm+ on a spin-bike as part of a charity fundraising challenge - quite a few rubs and missing bits of skin afterwards.....
I think the calibration within Zwift assumes a 700c wheel with a 23c tyre on it.....
When I set up Zwift it asked for which trainer I was using and also what wheel size, there is a drop down list for this, Zwift recommends resistance 3 for my trainer so I assumed this to be correct, as there is no link to zwift with the resistance setting it doesnt affect the reading on screen if I up or down the resistance.
I have the same Turbo with a road bike on though. Did the same to me. I just manually lowered my FTP to give more realistic top power.
That's Zpower for you.
It's a bit of a bodge tbh, or a cunning ploy to get everyone to buy a Smart Trainer.
If you plan on using Zwift a lot then a Smart Trainer makes sense in the long run. The Tacx one I got was sub- £200 and works rather well.