There is a setting to ‘Reset Install Angles’. That said, it doesn’t seem to help much. Next time I move them, I think I’ll try taking the batteries out and reinstalling them a couple of times.
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After resetting install angles it (PCO?)) went from
- -2 / +8
to - 0 / +10
Same same IMHO, until someone educates me otherwise. Still a delta of 10 between left and right.
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Did you use a torque wrench when installing? I found that resolved all my issues when I first got them. Unfortunately they have a very high torque spec, and you need a “crows foot” to use a torque wrench on them.
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Yes I used the torque wrench and crows foot on first Tarmac and Giant Escape installs. Then second Tarmac install I did it the GCN video way by hand/feel.
Welcome to the Rabbit Hole.
A couple of random thoughts:
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Your quantity of graphic figures in a single forum post is admirable. I can’t even get one image to show up properly half the time, let alone an entire college statistics textbooks worth.
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In general, I throw away the first ride after installing pedals (from any brand). There are exceptions. I usually find that if I go and ride a few minutes and do some solid hard/sharp sprints (3-4x), it’ll settle nicely. It still seems to take a full ride or so to be spot-on, but the sprints have long been a mainstay of power meter testing, even before pedals (chainrings back then).
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I don’t use a torque wrench on Rally/pedals anymore, mostly cause I just know by feel what it should be (which is slightly beyond normal tight, but very much short of gorilla tight). Again, the sprints usually sort this out.
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I only bother to trim MMP chart data if I’m missing some relevant spike/sprint. For example, let’s say I forget to start a unit 2 minutes late, but that two minutes is just easy pedaling out of a parking lot - I won’t bother there, because it won’t visibly show up. Whereas if during that two minutes I decided to exit the parking lot at the highest sprint of the day, then obviously, that’ll show up.
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Don’t bother comparing 1s max sprint power. There’s far too many nuances of recording rate/timing to sort that out. The only exception is if you’re talking like 150w off. But if you’re looking at 30-70w outdoors on a very brief sprint peak lasting literally only a couple seconds, it’s near impossible to compare.
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You can sometimes get weird differences between BLE & ANT+ that I’ve seen. I don’t have any good answers there, but it’s why virtually everyone who does power meter testing sticks to one side (usually ANT+). Also, I’d never trust a BLE connection to a dual-sided power meter for power meter testing purposes. Too many companies still screw this up. Single sided is fine, almost nobody screws that up.
Ultimately, what you’ll find over time is power meter testing is rarely satisfying, and rarely are there good answers as to why a unit might be slightly higher or lower on a given day - from all units. Instead, I aim to figure out trends on which units are most consistently reliable. Throwing a trainer in there helps, as it allows you to get ‘best 2 out of 3’, but I’ve got plenty of provable times where ‘best 2 out of 3’ still meant 2 were wrong and one was right.
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Thanks, I just returned from your post-doctoral thesis (and slow page loading) on the Rally power meters 
I’m not power meter testing, I’m simply doing a sanity check. Agree with everything you said, and have seen the same.
What I found weird, and slightly disconcerting, was to see the L/R balance shift from right to left, then back to right, and then slowly settle down closer to 50/50 (47/53).
That said, after a week of settling down, the total power is ‘good enough’ when compared to the SRAM Red/Quarq.
Have a great day, long time reader (2012?) and supporter of your site.
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Maybe this is due to the Quarq just estimating L/R balance from a specific pedal stroke model. If you have a slightly quirky pedal stroke, the estimate could be off.
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Doesn’t explain my experience with Stages gen2 single sided against Kickr, and gen3 left/right. I guess we can hand wave gen3 away by saying Shimano Hollowtech and right side power (in)accuracy 
Force and Red cranks might use slightly different spider designs, maybe, or I’m thinking of the 8 bolts. No matter, I’d guess the L/R estimation algorithm is similar/same.
I dunno, not trying to go off into the weeds. Total power and power curves seem close enough. Rally pedals seem fine so far in my sanity checking. I’ll continue dual recording a couple times a week, just in case, for another week or two.
Unlike our Quarq power meters, your gen 3 Stages and the Garmin pedals do not estimate left and right power, they measure both separately. So the latter do not use any L/R estimation algorithm. Of course, it doesn’t explain away discrepancies between all these power meters.
But if you made it your goal to stay within a certain L/R balance window, say, 48/52–52/48, then you base your L/R power balance off of one single source of power, trusting that this number is accurate. In my experience, though, simply displaying L/R balance and wanting to stay away from more extreme splits is enough to. (I noticed that after switching from a one-sided 4iiii power meter, I had developed a significant imbalance — at least if my Quarq is to be believed.) Point being, you don’t necessarily know whether 50/50 actually is 50/50.
The Stages has to deal with the Shimano crankset, so I don’t know whether I’d put more stock in those numbers than the Garmin pedals … 
Deep diving on power meter data is a big mess. (When I found out that my Elite Suito and my Quarq DZero started disagreeing significantly about how much power I was putting out, it really triggered my OCD. Eventually, I decided to simply declare my Quarq as the “source of truth”, not least because I was relying on my Quarq when riding outdoors.
I’m having an issue with the left pedal of one of my sets: It shows low battery (on the 1040, and garmin connect), even after swapping with new CR1/3N batteries (tried 3 new ones, same kind I’ve always used, and double checked they are outputting 3V) .
Is there a fix other than replacement?
I am running sofware 4.1
Garmin is claiming that there is a new door design since a year ago, and they’re sending some of these.
I’m skeptical (because I swapped pedal doors already) but hey, who knows.
anyone have the balance go whacky mid ride before? Mine have been great, but this last weekend, 6.5 hours in to the race the balance went nutso.
First time at BWR AZ on March 5 2023:
47%/53% left/right, clearly right side biased at the end, however REI installed the pedals. First use.
Next ride on my bike March 13, 2023:
41/59 holy right side bias!!! Enough to make me think my total power was slightly inflated. But not sure.
Next day, March 14: 2023:
65/35 left side biased, are these like a switch hitter in baseball, seriously WTF???!!!
Next day, March 15, 2023:
44/56 right side biased (look at later in the ride), you gotta be kidding me???!!!
2 days later, March 17:
47% left, 53% right. This looks better, you can’t see the center line on the graph.
next day, March 18:
49/51 left/right, things a settling down.
Two days later, March 20:
47/53 left/right.
Whatever. Good enough. Back to my Quarq (SRAM Red crank) as source of truth.
Also FWIW:
notice how the left/right balance goes whacky after 5 hours. The first 5 hours are - visually - around ~200W, and then your power drops over roughly ~1 hour and hour balance goes from 50/50 to left biased.
Yes. Looking at the GC page I can see you’re on firmware 4.1…so it won’t be for the same reason mine went whacky.
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Hi- Wondering if you got the seated/standing time issue sorted out? I am going around in circles trying to resolve (device reset, pair/unpair/re-pair, etc.). Edge 840 + XC200 + latest firmware. It’s either zeros or null for both 9/10 rides. Occasionally random numbers. Garmin tells me it’s a personal problem as there are no widespread complaints regarding this issue. Any guidance would be greatly appreciated!
Harris
Sounds like Garmin wants to shirk responsibility. Even if it is a “personal problem”, it is theirs to figure out.
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I’d agree with Oreo, that it sounds like you’ve got a non-awesome person on the other end of support (pretty rare for the Vector/Rally support folks, who are actually usually the opposite end of that spectrum).
In any event, for funsies, try pairing up your XC200 with some other power recording app, to try and narrow down if it’s the pedals or the Edge causing issues. That could be TrainerRoad, or honestly even just the free Wahoo Fitness app is a good one I sometimes use as a backup recording method for power meter testing data. When doing that, turn off your Edge unit, to ensure it’s not causing the issues somehow. If you’re getting dropouts there, then it narrows it down to the set of pedals. Whereas if you get nothing, then somehow the Edge may be the issue.
4 Likes
Hey Harris,
I had forgotten about this. I am looking at my recent outdoor rides and it looks like it is capturing standing / seated time on my Edge 1040. I have found one case during an indoor ride recorded on my Enduro2 where it seemed to capture nothing until the last 30mins of the ride. I am looking thru my rides now.
I am sorry to hear you are having a poor experience with Garmin. I’ve had solid support from them across several devices to include a replacement set of XC200s. My pedals seemed to be dropping out cycling dynamic data intermittently during the ride. They then show no drops I the data on GC. I was sent a new set. I see it happen occasionally now but do not think it’s impacting my data.
If it makes you feel better, I’m having issues (not this specific one) with my pedals too.
My numbers are higher on my XC rally pedals AND my trainer by 20% but I can’t do the same ride over 2 sets of pedals and a smart trainer to prove it lol. I’ve sent them screenshots of my (garmin) HRM though and anecdotes to try and sort something out. I know they can’t just send new pedals out but I would be interested in returning these for a replacement pair. Otherwise I’m getting the Faveros.
I’ve tried different torque settings and different bikes and new batteries.
Garmin also say Pedals and smart trainers read differently. However they say smart trainers should read lower, the opposite issue to me.