Ok so im really confused and hope someone has some kind of answer. A few months ago I bit the bullet and at the recommendation of most people on here I bought a set of PowerTap P1’s. Side note you were all right. I was dumb to wait so long. They are awesome. Ok now that’s out of the way I don’t understand why there is such a difference in my power numbers riding indoors on Zwift vs Outdoors? They are pedals and they don’t know where I am so that should not be a factor. At first I thought maybe Zwift was doing some behind the scenes magic to do…I have no idea why they would do that but I have them linked to my 920xt and have watched that while riding and the numbers match Zwift so nothing there.
According to Zwift the highest power I have ever put out is 699 watts. That was during an all out sprint where I thought I was going to rip the bike out of the trainer. Today I rode outside. Had an absolutely rubbish ride. Could not keep my heart rate under control avg 17.9 mph but I topped out at 791 watts?
I find my power #'s are always higher when I’m riding outside vs on the trainer but I feel like im putting out a similar effort. Any ideas?
P1 pedals are single sided. If you have a significantly stronger and weaker leg the P1 will read off but a noticeable amount.
You don’t say what trainer you are using, but they all measure power at the wheel (assuming you have a wheel on trainer). That means it is not estimating your power off of one leg, but actually measuring the total power. Some trainers are more accurate than others, and if you have a wheel on trainer the coast down setting can make a big difference. Also, most trainers measure power lower as they get warmer, which is why you are told to do a coast down after about 30 minutes of riding.
Finally, have you put the bike with the pedals on the trainer and watched to see how they track to each other?
So I have the double sided pedals and I have them synced to Zwift not the trainer. I had not thought about how Zwift can only see one of the pedals and not both. I wonder if that’s the discrepancy. I’m using an Elite Real Axiom wheel on trainer. When I got the pedals there was about a 30watt difference between the pedals and the trainer (trainer was 30 watts lower than pedals) so I never use the trainer to report power to swift. I just let Zwift talk to the trainer to adjust resistance and get power and cadence from the pedals.
P1 pedals are single sided.They had 2 versions. The P1 were dual-sided, and the P1S were single-sided.
Back to OP… Are you measuring power from the pedals both on and off the trainer (like a Power Match option)?
I find that I generate power more comfortably outside than inside. I credit this to the natural headwind versus my little fan. Plus, I think the more dynamic position on the bike helps.
Comparing max power is probably not a good indicator. When you are outside, you can sling the bike around and get a very different position than on a trainer that generally hold the bike rigid. What I would look more at is RPE, average power, and normalized power. I do always get higher power numbers for a similar RPE outside, but it is probably on the order of 5% more.
You can easily do a short spike like that outdoors coming out of a corner, the first time you stomp on the pedals… On the trainer, resistance is controlled by the trainer so you don’t have too much coasting and big differences in force. Anyway… that’s my explanation. Your pedals are fine.
Ok so im really confused and hope someone has some kind of answer. A few months ago I bit the bullet and at the recommendation of most people on here I bought a set of PowerTap P1’s. Side note you were all right. I was dumb to wait so long. They are awesome. Ok now that’s out of the way I don’t understand why there is such a difference in my power numbers riding indoors on Zwift vs Outdoors? They are pedals and they don’t know where I am so that should not be a factor. At first I thought maybe Zwift was doing some behind the scenes magic to do…I have no idea why they would do that but I have them linked to my 920xt and have watched that while riding and the numbers match Zwift so nothing there.
According to Zwift the highest power I have ever put out is 699 watts. That was during an all out sprint where I thought I was going to rip the bike out of the trainer. Today I rode outside. Had an absolutely rubbish ride. Could not keep my heart rate under control avg 17.9 mph but I topped out at 791 watts?
I find my power #'s are always higher when I’m riding outside vs on the trainer but I feel like im putting out a similar effort. Any ideas?
Thats makes sense. Had not thought about it from the coasting to hammer phase. I did a few short sprints but nothing I would feel were worth mentioning.
If you connect the pedals to Zwift using Bluetooth, you are only getting one side power which Zwift is doubling. For some reason, when the P1 pedals connect by Bluetooth they cannot cross-communicate.
If you are connected by ANT+ you will get proper dual-sided power.
I know that my left leg is stronger than my right. So when I connect by BTLE I wind up with seemingly larger power numbers than I am normally capable of.
If you connect the pedals to Zwift using Bluetooth, you are only getting one side power which Zwift is doubling. For some reason, when the P1 pedals connect by Bluetooth they cannot cross-communicate.
If you are connected by ANT+ you will get proper dual-sided power.
I know that my left leg is stronger than my right. So when I connect by BTLE I wind up with seemingly larger power numbers than I am normally capable of.
Yep - if you look on the zwift pairing screen you’ll note you have the option to pair either pedal, but not both at the same time.
What I do is calibrate my kickr and use that to control, and then I pair my pedals to my 520 as a second set of data. Annoying, but gives reliable info to my head unit I can take outdoors
My powertap p1 pedals show within a few watts of my TacX neo 2t, I do not use them on Zwift as I have my trainer setup to do all of the metering minus cadence, which I use the pedals for.
If you connect the pedals to Zwift using Bluetooth, you are only getting one side power which Zwift is doubling. For some reason, when the P1 pedals connect by Bluetooth they cannot cross-communicate.
If you are connected by ANT+ you will get proper dual-sided power.
I know that my left leg is stronger than my right. So when I connect by BTLE I wind up with seemingly larger power numbers than I am normally capable of.
Yep - if you look on the zwift pairing screen you’ll note you have the option to pair either pedal, but not both at the same time.
What I do is calibrate my kickr and use that to control, and then I pair my pedals to my 520 as a second set of data. Annoying, but gives reliable info to my head unit I can take outdoors
I don’t use Zwift, so I can’t speak to the pairing screen, but I know my P1 pedals (dual sided) only ‘communicate’ through the left pedal. It is still dual sided power, but the right pedal relays data through the left pedal. That’s also why you will see people post about a ‘right pedal missing’ message when first pairing with a head unit.
So for my non-Zwift experience, it is still possible to get dual sided power even if only paired to one pedal.
I’m fairly certain P1’s only send left side power data over Bluetooth which is then doubled. Dual sided power readings require ANT+ connection. Do you have a link that says otherwise? I’d be thrilled to hear that as it makes me jealous of the Assioma Duos that do truly broadcast both sides through the left over BTLE
That could explain it, I only ever use my P1 set with ANT+ connections (either Garmin 520+ or Suunto dongle).
EDIT: I also found that link (should have just clicked on yours) but it’s interesting that it is a pairing issue and not a pedal issue. If Zwift allowed you pair to both pedals, it would be ok. I guess maybe the Favero firmware adjusts for that.
But to the OP - if you use an ANT+ dongle that would at least fix the single-sided issue indoors, if that is in fact an issue for you.