Hey,
Just got a trainer today, and tried it out for the first time. I have used trainers in the past, and have had a powertap for a while. My experience in the past has been that it’s generally harder to generate the same power riding inside relative to riding outside. Reading posts online seems to corroborate this, too.
However, this is my first time using a magnetic trainer (Ascent magnetic), and I found that I had no problems putting out comparable power compared to riding outside. It seems like the powertap would read independently from any variable inputs from the trainer. But, I just wanted to make sure there’s nothing i’m missing, re: adjusting the roller position that would bias power readings to increase, especially since I want precise kJ expenditure totals.
Thanks,
Do you coast a lot outside?
Or live in an area where constant pedaling is not possible? Lots of traffic? Stoplights and stopsigns? Or lots of up and down?
Not necessarily; I ride on plenty of roads where I don’t need to stop for upwards of 45 minutes. But who knows, maybe I coast more than I realize outside, and the trainer just makes me more consistent re: sustained power.
I was mostly interested in any mechanical explanations stemming from trainer adjustments. Am I right in assuming that the powertap reports values based purely on torque and cadence, and will not be affected from one trainer to another? I’ll be sure to zero out the powertap again when I ride the trainer tomorrow (the weather in the SE sucks this week).
Doesn’t matter what your trainer settings are. If you’re using a powertap, it’ll tell you what your power is.
I have no problems putting out comparable power to outdoors for efforts that aren’t very hard. However, once I start pushing my limits, that 5-15 watt differential does become noticeable. Do some FTP tests or hard intervals, and report back on whether it’s still true then.
I’m coming to the conclusion that magnetic resistance just doesn’t work for me, I have the same problem as you, higher power indoors than outdoors with magnetic. This is not a good thing, in that what happens over time is that my outdoor power reduces to below my indoor power, rather than my indoor power being much higher than with a fluid turbo.
In the last two months, training on a magnetic turbo, my indoor power has improved by tens of Watts, but my outdoor power has fallen. I used to have this problem with rollers, also magnetic resistance, so I’m coming to the conclusion it’s magnetic resistance that is the problem. It’s a shame as I much prefer the Tacx magnetic turbo to the KK due to the smaller roller giving less tyre slip, and the quick release roller clamp being so much better than the KK’s screw roller clamp, but I think I’m going to have to give up on it, because my outdoor power is tens of Watts below where it should be for what I’m doing indoors.
Make sure that after a warmup you do a ~6 second coast from highish speed so the powertap can autozero. Or stop and zero manually, that would be better.
It could be your new trainer has a better flywheel mass to your body’s liking, making it easier to do the same power as outdoors.
Hey,
Just got a trainer today, and tried it out for the first time. I have used trainers in the past, and have had a powertap for a while. My experience in the past has been that it’s generally harder to generate the same power riding inside relative to riding outside. Reading posts online seems to corroborate this, too.
However, this is my first time using a magnetic trainer (Ascent magnetic), and I found that I had no problems putting out comparable power compared to riding outside. It seems like the powertap would read independently from any variable inputs from the trainer. But, I just wanted to make sure there’s nothing i’m missing, re: adjusting the roller position that would bias power readings to increase, especially since I want precise kJ expenditure totals.
Thanks,
I find it’s slightly easier outside mentally to push hard and time goes by a little quicker…especially at lower intensities, but my HR is actually lower indoors at the same RPE by at least 5bpm. I suspect it because controlling the bike and absorbing bumps, wind, etc requires a little more energy compared to indoors. TI could also be a difference in muscle adaptation and will level out with more outdoor rides.
Overall I don’t see a huge difference… which is good since I’ve been riding over 90% indoors this winter and probably will until at least mid April after crews have pated a lot fo the potholes and ice is no longer a concern ot venture out in the morning wit ha headlight. Damn daylight saving time! It was finally almost getting light enough now.