First powermeter - P2M NgEco / Favero Assioma Duo

[Rudi]

Hi krisJ

Looks like you have made up your mind. I was just going to say that the Assiomas have been great for me. No issues for me, good battery life, easy to swap and travel with. Power readings are in line with my smart trainer so accurate enough for me. I've never used a cranked based PM so can't compare.

I've skimmed the topic but didn't see anything about the cleats. They are Look keo compatible, I've never had any issue with that. My wife (who I share them with i.e. they are hers) finds it easier to clip in and out of with the Favero BePro specific cleats. She has come from SPD-SLs though and I've always had Look. They should come with a set of the BePro so you can figure out what you prefer.

[TobinHatesYou]

Yep, the real Look cleats are a bit "tight" at first but they get worn in enough that they clip out fairly easily. It's still not 100% compatibility. Also the Assiomas seem to go from heavy spring tension at the lowest setting to ridiculously heavy. There's no truly easy setting.

As far as the OP's choice goes, I think the only con of pedals is how exposed they are in a crash, but then again I've crashed my Vector 2s ... several times and they've remained functional and accurate.

[chiefspinninggear]

Given the development of power meters as a whole, look at if you are wanting to swap between bikes etc. I wish i went with vector 3's as opposed to a quarq system but hey ho!

Sent from my SM-G950F using Tapatalk

[pedale]

Soon all bike at ultegra level will be sold with power meter. Giant as already started with power pro and SRAM makes them disposable with AXS. Better have an easy to move power meter than one bound to BB standards.

[krisJ]

The reason i choose the pedals is just the fact how easy they are to use (or seem atleast -, receiving the pedals monday next week), and I can easily bring them with me while travelling, or to a new bike.

Regarding the cleats. My current pedals are the ultegra R8000's, been quite happy with them in general. But I guess it wont be too big of a problem getting used to a different system?

[pedale]

Shimano pedals are better enough to be noticeable, but I prefer to ride with my GPS displaying this number that I found always lower than what I expected

[robertbb]

You won't regret it. Excellent product in every way - Favero knocked this out of the park!

[TiCass]

Given the development of power meters as a whole, look at if you are wanting to swap between bikes etc. I wish i went with vector 3's as opposed to a quarq system but hey ho!

Sent from my SM-G950F using Tapatalk

Yeah but then, you would expect your Vector 3 to work as good as the Quark. It's just not the case.

[TobinHatesYou]

Yeah but then, you would expect your Vector 3 to work as good as the Quark. It's just not the case.

My Vector 3s are more consistent from one zero to the next than my DZero. The DZero misbehaves during soft pedaling as well.

[Calnago]

Yeah but then, you would expect your Vector 3 to work as good as the Quark. It's just not the case.

My Vector 3s are more consistent from one zero to the next than my DZero. The DZero misbehaves during soft pedaling as well.

What does that mean... “more consistent from one zero to the next”?
And how often do you switch your DZero between bikes to be able to even be able to make such a comparison?
And why are you even comparing the relative consistency of your zero offset value (I’m assuming that’s what your talking about) from your pedal pm’s with a crank based powermeter?

[TobinHatesYou]

What does that mean... “more consistent from one zero to the next”?
And how often do you switch your DZero between bikes to be able to even be able to make such a comparison?
And why are you even comparing the relative consistency of your zero offset value (I’m assuming that’s what your talking about) from your pedal pm’s with a crank based powermeter?

I train indoors quite a bit and leave my extra power meters on the spare bike for the purpose of a three-way comparison between power sources.

There really should not be any significant difference in power measurement between a spider, crank or pedal based PM. They are for all intents, rigid structures in front of any drivetrain losses. Also downstream power meters like PowerTap hubs and smart trainers assume drivetrain losses of around 2% in their math anyway...the same goes for Quarq's auto-zero via backpedaling 4x. When the DZero is behaving, it is within 1 watt of my Vector 3, Assioma Duo and CycleOps Hammer in the 200-400W range. When it is out, sometimes the drift will be 5-10W while the other two units are still within 1-2W. Since I train indoors in a "pool house," I sometimes use a small Vornado heater to raise the ambient temperature a bit before I hop on the bike. The DZero drifts when a zero offset is performed with the heater turned on. No other power source I own drifts noticeably in the same conditions.

Here is an example from last week:
https://analyze.dcrainmaker.com/#/publi ... 7203800516

Note the Hammer does overshoot on accelerations quite a bit. The shorter mean-max power values skew more because they are in part measuring heavy accelerations.

[Calnago]

The only thing you said that makes any sense and is still not related to my questions is that they should all measure 100watts of power as 100watts. The zeroing out before each ride is to account for changes in temp etc. Perhaps it is your crank based unit that is “behaving” better than your pedal based units. But I wouldn’t trust any “autozeroing” done with feet in the pedals as that can introduce more errors than if you have the autozero function turned off. Tested it with SRM units and as a result of those tests I “calibrate” before each ride but keep the autozero function turned off. If I’m out for an all day ride and the temps have fluctuated enough I could zero it out again during the ride, feet out of the pedals, standing still. I don’t do that because I don’t care but from a purely academic standpoint that’s what I’d do if I did. The point is you want consistency within the powermeter itself from ride to ride and absolute accuracy would be nice, but relative accuracy within itself is just as good if you’re only comparing your own wattage numbers, versus trying to compare with others.
None of what you wrote came close to answering the questions I posted. Sorry for asking.

[TobinHatesYou]

Nothing I say will ever satisfy you, so there’s no point in continuing this discussion.

[pdlpsher1]

Thanks for sharing the power data. I reviewed the data in 5-minute increments and all three PMs track very closely. If anything I think the hammer is not as consistent as the other two (on peaks the Hammer reads higher, on troughs it reads lower). The only part where I see some discrepancies is from 1:30 to 1:35 where the Quarq is reading lower than the other two. But just because you have two PMs agreeing and a third PM disagreeing it doesn't mean the third is inaccurate. If you exclude the 5-min segment I think the data looks remarkably consistent. Lastly it would somewhat make sense that the Quarq's reading being slightly lower than the Vector based on the different locations of strain gauges (Quarq lower by only 2w. in avg. power). I think Quarq's temp. compensation works very well. Today I did a ride in frigid temps (15F avg. with a low of 8F). I didn't notice any power measurement anomalies despite the frigid temp. For a reference my zero offset is around 72 and it varies by less than +-3.

[TobinHatesYou]

Thanks for sharing the power data. I reviewed the data in 5-minute increments and all three PMs track very closely. If anything I think the hammer is not as consistent as the other two (on peaks the Hammer reads higher, on troughs it reads lower). The only part where I see some discrepancies is from 1:30 to 1:35 where the Quarq is reading lower than the other two. But just because you have two PMs agreeing and a third PM disagreeing it doesn't mean the third is inaccurate. If you exclude the 5-min segment I think the data looks remarkably consistent. Lastly it would somewhat make sense that the Quarq's reading being slightly lower than the Vector based on the different locations of strain gauges (Quarq lower by only 2w. in avg. power). I think Quarq's temp. compensation works very well. Today I did a ride in frigid temps (15F avg. with a low of 8F). I didn't notice any power measurement anomalies despite the frigid temp. For a reference my zero offset is around 72 and it varies by less than +-3.

pdlpsher1, the Hammer overshoots any time there is an strong acceleration. This is a known issue and it affect all Hammers...it also affects most flywheel based smart trainers. The only ones I know that don't do this are the Tacx Neo and Elite Drivo.

I also have probably 100 sessions recorded with combinations of the DZero, Hammer, Vector 2, Vector 3 and Assiomas, so I can see obvious trends and groupings. The DZero is the only one that occasionally drifts by more than 2% in steady state intervals (no accelerations.) There have been a 2-3 sessions where the other two PMs tracked consistently with each other and the DZero would just read >5% low. You've also made the assumption that my DZero is supposed to read low and usually reads low. That is not the case and it occasionally reads high. As I stated earlier, the difference in measured power should be practically nothing between a pedal-based and spider or dual crankarm power meter. You are not losing 2W in hysteresis to components bending / heating up between a spider and a pedal. This are for all intents, single piece structures.

Unless you have multiple power meters and (3 minimum, more = better,) I don't see how you could say you haven't noticed power measurement anomalies. These anomalies aren't obvious spikes...they're just a couple of watts worth of drift.