First powermeter - P2M NgEco / Favero Assioma Duo

Discuss light weight issues concerning road bikes & parts.
User avatar
pdlpsher1
Posts: 2390
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Thanks for the detailed response Eugene. Well, maybe it's a good thing that I only own one PM. I really do think that minor anomalies are just the nature of the beast on PMs. I have read many of DCRainmakers' PM reviews and basically he's saying that most of the mainstream PMs are very good in terms of accuracy. If you look at the power data in detail you'll never see two PMs read the same. One will be higher at times and lower at other times. Now I think 5% diff. is quite substantial and I hope those are very isolated incidents (you mentioned 2-3 sessions out of 100).

On the power loss between the Quarq and Vector, I gave it more thought and I think you are correct. The Quarq is calibrated with a known weight at the pedal axle. So the power reading on a Quarq is determined by the amount of force applied at the pedal. The power measurement ignores the flexing of crank assembly and also any frictional losses in the BB bearings.

by Weenie


TobinHatesYou
Posts: 3795
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

pdlpsher1 wrote:
Sat Feb 09, 2019 7:58 am
Thanks for the detailed response Eugene. Well, maybe it's a good thing that I only own one PM. I really do think that minor anomalies are just the nature of the beast on PMs. I have read many of DCRainmakers' PM reviews and basically he's saying that most of the mainstream PMs are very good in terms of accuracy. If you look at the power data in detail you'll never see two PMs read the same. One will be higher at times and lower at other times. Now I think 5% diff. is quite substantial and I hope those are very isolated incidents (you mentioned 2-3 sessions out of 100).

On the power loss between the Quarq and Vector, I gave it more thought and I think you are correct. The Quarq is calibrated with a known weight at the pedal axle. So the power reading on a Quarq is determined by the amount of force applied at the pedal. The power measurement ignores the flexing of crank assembly and also any frictional losses in the BB bearings.

I think that yes, instantaneous power may differ from one recording to another due to the nature of polling rates and filtering, and I do think that most power meters are sufficiently accurate. Averaging power over 60 minutes should result in numbers within 1-2W. I don't mind when the Quarq is within 1-2W, it's more the rare occasion where it jumps to ~10W off that bugs me.

The Quarq is one of my newer PMs, so I probably only have 30 or so indoor sessions with it. A handful of rides out of 30 with it being pretty far off is a bit more substantial than the 100 total with various combinations. It's enough data, though, to see trends and I am confident that the Quarq's numbers are more variable than the others from ride to ride.

Perhaps my particular Quarq is faulty, but its offset never varies more than 20 when they say 50 is acceptable. I need to add a P2M to my collection at some point.

Pinguin
Posts: 101
Joined: Fri Nov 02, 2018 9:28 pm

by Pinguin

TobinHatesYou wrote:
Sat Feb 09, 2019 8:11 am
pdlpsher1 wrote:
Sat Feb 09, 2019 7:58 am
Thanks for the detailed response Eugene. Well, maybe it's a good thing that I only own one PM. I really do think that minor anomalies are just the nature of the beast on PMs. I have read many of DCRainmakers' PM reviews and basically he's saying that most of the mainstream PMs are very good in terms of accuracy. If you look at the power data in detail you'll never see two PMs read the same. One will be higher at times and lower at other times. Now I think 5% diff. is quite substantial and I hope those are very isolated incidents (you mentioned 2-3 sessions out of 100).

On the power loss between the Quarq and Vector, I gave it more thought and I think you are correct. The Quarq is calibrated with a known weight at the pedal axle. So the power reading on a Quarq is determined by the amount of force applied at the pedal. The power measurement ignores the flexing of crank assembly and also any frictional losses in the BB bearings.

I think that yes, instantaneous power may differ from one recording to another due to the nature of polling rates and filtering, and I do think that most power meters are sufficiently accurate. Averaging power over 60 minutes should result in numbers within 1-2W. I don't mind when the Quarq is within 1-2W, it's more the rare occasion where it jumps to ~10W off that bugs me.

The Quarq is one of my newer PMs, so I probably only have 30 or so indoor sessions with it. A handful of rides out of 30 with it being pretty far off is a bit more substantial than the 100 total with various combinations. It's enough data, though, to see trends and I am confident that the Quarq's numbers are more variable than the others from ride to ride.

Perhaps my particular Quarq is faulty, but its offset never varies more than 20 when they say 50 is acceptable. I need to add a P2M to my collection at some point.
Tobin if you buy a new Pm now,which one would you choose?

TobinHatesYou
Posts: 3795
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Pinguin wrote:
Sat Feb 09, 2019 5:12 pm

Tobin if you buy a new Pm now,which one would you choose?

Favero Assioma Duo.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post