Here’s a massive dump of information I’ve been meaning to put together for a while in regards to ‘where things are at’ with the power meters I have (and am) testing in the Lama Lab.

Shimano Road Power Meter(s)
There are well documented problems with all generations of these meters. I’ve done four or five deep-dive video reviews on these over the years and have a detailed report on my website. Keith Wakeham (former 4iiii employee) has also published a number of even deeper dives into the Shimano meter issues, specifically the right side crank design and why Shimano and others who use the same crank have problems with it. Shimano never admitted any issue but the latest firmware update that ‘improves accuracy’ by pairing the meter to the Di2 group to scale the right side power based on what chainring you’re in says enough… and also confirms what I’ve reported on all along. Their left meter data is fine (that crank arm is symmetrical)… but they don’t offer a single side option. I spoke to Shimano representatives in person at an event at Eurobike this year. I was told pro teams are happy with their meter. Apparently they test with power pedals. Me too, although my data shows their meter is still no good. I offered to re-test if they could supply units. They didn’t see any value in doing that as “it was time to look to the future”. I hope that means they’re working on a real meter and not some lick-and-stick afterthought to their standard cranksets. I’d like to see Shimano acquire SRM or Power2max and call it a day… although one of those isn’t quite the ‘gold standard’ people like to label them as.

4iiii Innovations P3
It took 4iiii a very long time to sort out early issues with their “new” P3 sensor. The single sided version now tests well. I’ve had two or three Shimano road dual P3 cranks sent over for testing, none were really stable on the right side and had shifting offsets during a ride or were susceptible to issues AFTER a manual calibration/zero offset in the field. I’m planning on looping back to the Shimano 12spd dual soon to finally get that off my plate. They’ve recently had to redesign their battery cap/housing due to regulations in some markets. Their Apple Find My integration is a neat value-add. The P3 will only switch to ‘Find My’ mode when the power meter is asleep (4mins of inactivity).

Stages (Pre Shimano 12spd)
Don’t bother with Stages prior to Gen 3/III. Gen 3 isn’t exactly new, being released around 2018. Prior to this the ANT+/BLE range was way too short. Left only tests well. Dual sided on the Shimano road cranks never tested well – related to the asymmetry of the Shimano right side crank arm design. Stages tend to over-read with new batteries installed. This hasn’t been observed in any review that I’m aware of (even mine) as by the time most units are tested the battery has dropped into the Goldilocks zone below ~92% where the numbers test ok (on the left, or on symmetrical cranks such as the XTR). Stages Cycling as a company has had an interesting few years post Covid. They’re now owned by the Giant group.

Stages (Dual Sided Shimano 12spd Ultegra/DuraAce)
These get their own paragraph as they’re nothing short of a miracle. Same Gen III sensor but on the right side of the 8100/9200 crank they wrapped the sensors on the leading and trailing edges of the right crank and it tests really well. Echos of “Wholly shit! What!?” were heard from the Lama Lab when testing these. As I recall, I tested both 8100 and 9200 with good results. These will still likely have the overread issue with fresh batteries. Something I’ll loop back on when I get time. Also worth noting these are still the lick-and-stick aftermarket design that come with all the same risks/issues as other meters using this design.

SRM PM9
The “Gold Standard” in high pricing and reputation. As for the data, it’s a long story. I have N=1 that I’ve been using for almost two years now. It reads a little higher than other meters in steady-state efforts. A static weight test confirmed the slope was a little high. Factoring in the adjusted slope, the numbers would line up a lot better. The PM9 slope can’t be adjusted by the end user. The unit has to go back to SRM. Not ideal. This unit also has an issue with residual torque (which I’m not sure is the technically correct term, but it’s what I call it). After a peak power sprint (~1200W on a good day for me) the unit will read higher. Using their app to check the realtime torque it’s bouncing around 0.3 to 0.4. A difference of 0.4Nm at 93rpm using 172.5mm cranks results in ~3.89W which is pretty close to the ~4.1W increase I was seeing from the PM9 after the sprints (and was zero’ed out after the calibration). Long story short, the PM9 is off the bike and they’ve said another will be supplied. I’ve been giving SRM a shitload of runway to get this right… They’re good people but they don’t seem to be in any rush.

SIGEYI
It has been a while since I tested any of these spiders. Latest data from the Lama Lab is 2023 were I was re-checking a SIGEYI spider my wife has been using on her gravel bike (SRAM 1x). That was still reporting exceptionally well against the Direto XR and Assioma DUO at the time. Battery life seems to be fine on it too. Back in 2023 I installed a RaceFace SIGEYI spider on an MTB that needed scaling of some kind but then read low in peak power sprints. I didn’t dig too much into that before removing the cranks and installing something else.

Garmin RALLY
These are technically the Vector 3 (iirc they have the same FCCID). Thanks to SRM, Garmin don’t take the prize as the most expensive power meter pedals. The Vector/Rally is an interesting design with the electronics inside the spindle but the batteries being housed externally in the pedal bodies. The interface between the spindle and pedal body for power is quite interesting! Their battery cap issues seem to be resolved after years of complaints (and revisions). Switching over to the single CR1/3N battery (which I think was first offered up as a hack by an owner before being adopted by Garmin) was a good move. Numbers wise they seem fine. I’ve had some random issues with residual torque after peak power sprints. This caused over-reading after the sprints. Manually zeroing them resolved the problem. Also worth noting the real time torque on the EDGE was showing a positive number before returning to near zero. This may have been isolated to particular cranksets… I didn’t get to the bottom of it. I’m also able to have them completely shit themselves in maximal sprints. Swinging the bike (a lot!) side to side like a wildman throws the accelerometers out to a point they read 0, in turn it can’t calculate power. Reported to Garmin. It’s an acknowledged issue, well, it has to be, I can repeat it and I have the data. Won’t be resolved with current hardware. Not common so not a problem, I guess.

Quarq / SRAM AXS
SRAM acquiring Quarq was such a good move. If you have a SRAM groupset then choosing a meter that’s compatible is straight forward. There’s no messing about like with other spiders trying to find a crank, rings, bottom bracket, etc. Quarq power data is typically good. Their MagicZero auto calibration usually means things align well throughout a ride. It’s not perfect though as it can cause some issues if you stand on one leg with weight on the right crank (and the sun and moon align at the right time of day) – MagicZero becomes TragicZero and zeros very poorly and your data won’t be accurate… until it kicks in again (maybe a few seconds later, maybe a few minutes later). Not a widely reported issue, or much to worry about, just something to know about. I’ve a had problem with one of their single sided spindle meters reading low (~6%) that was corrected by using their app to upscale it. SRAM have added a new post install calibration process within their app which might help? I’m having some accuracy issues with their newer threaded spider with the Force E1 group (2x setup). It’s not aligning within spec of a few smart trainers and other power pedals (so upstream and downstream of where it’s measuring). I’m in the process of collecting more data with other equipment.

IQSquared
Someone once called IQSquare the Fyre Festival of power meters. This is the perfect description. They DID make a power meter, just don’t tell any of their backers who they completely screwed over. They sent over a single sided power meter pedal that tested quite well (review video is still up on YouTube). I don’t recall ever hearing from them after my review was published, so it wasn’t just the backers they were ghosting. Some poor soul in Canada made it his side-quest to represent the brand for a few months there. He noped the hell out of that venture pretty quickly. I think he even left a comment on my video or somewhere? Fast forward to 2025 and an online retailer here in Australia (CCache) were offering IQSquare power meters in their store. They had stock!? Again, don’t tell the backers! Looks like that link is 404’ing now on their website. If you ever see these pedals, run the other way. IQSquare will forever be the in-joke that if you know you know, if you don’t, someone will explain it.

Power2Max
P2M have always been one of those ‘just works’ brands. People who have them seem to love them. No real issues to report with their meters. Spider meters are less appealing these days with the increase in popularity of pedal power meters that install in minutes and don’t require a compatibility research project prior to purchase. P2M pricing is also somewhat prohibitive for a lot of people. The Power2Max mobile app (needed for product activation) is an utter shitshow. 1.5/5 stars in the App Store. Only coming second to that time the XCadey website tried to install spyware in my browser. P2M are my second choice company that Shimano should acquire and call it done. That’ll also get them meters for road, MTB, and gravel!

XCadey
Similar to SIGEYI in their offerings. Their spiders performed well after a few replacements and a slight scaling to correct their numbers. This was five years ago. Their Gen II spiders have been on the market for a while. I’ve had a meet and greet with them at Taipei Cycle, China Cycle, and Eurobike… each time they’re keen to have the Gen II units tested in the Lama Lab. I’m still waiting to hear from them. *shrug*. I wouldn’t be putting any money down on them until we see some data… somewhere.

PowerTap Pedals
The classic! These chunky monkeys were a go-to in a time Garmin were still hanging pods off cranks. They were only single sided when using BLE (Dual channel was only via ANT+). Not user serviceable as I recall? I left some in a box with a battery in them that leaked and killed them. iirc the P2 version were identical to the V1 with a few grams shaved off under the cleat plate.

PowerTap Hubs
The nostalgia here is strong! And no, not about “my first” power meter…. but the months of frustration at trying to diagnose a power meter that would fail when the temperature dropped below 16℃. That was 17 years ago. And I’m still at it diagnosing power meter issues that shouldn’t exist! hah. Oh god. Power from these was never really tested to the extent we test things with today. I still have one that I should revisit.

Pioneer (Shimano Cranks)
One of the better performing dual meters using Shimano cranks. These DID have right side issues too. i had three units sent over as the team out of CA I was dealing with tried to ‘resolve’ the right side issues I was having with my testing. Whatever Shimano acquired wasn’t a fully working meter. Shimano added in the Pioneer force vector metrics, which are a waste of time if the meter itself isn’t correctly measuring force (see Shimano meter section above).

WatTeam PowerBeat
Their self install kit was a great idea to keep the cost of power meters down – by having the user glue the gauges and perform the calibration themselves with bags of water(!). It was just a lot of messing about for an end user. You could by pre-installed (iirc?). Seven years ago I posted a 24min deep-dive on YouTube that goes deep down the rabbit hole – with a big focus on the issues they had with measuring torque correctly on the right side crank (yes, there’s a theme here if that sounds familiar!).

ROTOR
I’ve had their 2INPower, 2INPowerSL, and INSpider meters through the Lama Lab over the years. Each one of them doing something strange with power data. iirc the 2INPower would read high indoors, low outdoors. The INPower SL did the opposite. The INSpider was also inconsistent. These inconsistencies are a total time sink trying to figure out where the problem lies. Rotor seem to be close to having a solid power meter, then I spot something in the data that indicates otherwise. They’re also banging on about having the most accurate power meter on social media. The data I have doesn’t agree. Rotor have recently been (mostly?) acquired by WheelTop. We might see WheelTop offering power with their groupsets in the future. Hopefully ones with more consistency.

Giant PowerPro (Shimano Crank)
This is personal as one came on the bike I purchased back in 2018. Same right side issues as most of these meters using the Shimano road crank. The MY20 version tested better but wasn’t great.

Giant HALO (Spider)
I have 26 data sets from these but can’t locate any review I’ve done… I know I killed one with a water crossing on the gravel bike. A quick review of the data from 2022 shows it was reporting 20W+ higher than the Rally XC200 at around 200-250W. Indoor testing shows about the same up against the Kickr 5 at the time. I likely shelved this and forgot about the review. Email logs show the last I heard from Giant on this was May 2022 “I hope we will solve and fine tune Power Halo soon.”

InPeak
Another company installing their sensors on (mostly?) Shimano cranks. Lots of drama early on with their initial meters having drifting offsets and power oscillations over time. To their credit, they addressed these very quickly and the result was a left only meter that was fine. That was six years ago. They have newer generation sensors on the market – I’m still trying to get some to test.

Magene
P505 and P505 Base Spider: Tested well. The P505-Base at US$299 for a spider/crank (no rings) is an extremely low price for a spider meter. And for one that tests well. The P515 is a slightly modified design on different alloy (as far as I’m aware).

P715 Pedals – I really hoped to see these priced at $299 or $399. They’re US $499, so Magene haven’t entered the race to the bottom for pedals. They also ship without cleats. Every pedal power meter comes with cleats, except these. Feature/spec wise they’re best compared with the now-eight-year-old Assioma DUO (not the Assioma PRO). I’ve been told they have a return-to-base servicing, although I’ve seen them pulled apart on the Internets already (voiding warranty?). I can’t locate these on their support site at this point in time to confirm what their official line is on that. Even if their data lines up to spec, there’s a few catches with these people need to consider. Claimed 120hr battery is double that of the competitors, at the cost of more weight. These aren’t light pedals by today’s standards.. Stay tuned for more on these soon.

Infocrank
Two of their OG meters were sent over in last 2022 that I had a few interesting issues with. At the time of testing, their meters were already 7-8 years old. Overall accuracy didn’t quite match their overly aggressive PR communications about how good their product is (was?). Discovering things like ‘cadence decay’ during my testing wasn’t ideal. Absolute boat anchor cranks by today’s weight standards. In 2022 they announced an updated model “IC2” that in 2025 I can’t see on their web store or find any concrete details about.

Wahoo Speedplay PWRLNK
I’m no fan of the Speedplay cleat system. Data looked ok from my rides indoors and out. Some reports of pedal play/issues – nothing I encountered while they were on the bike. Wahoo recently soft re-launched these with “Speedplay Power” branding. I’m unsure of any changes to the pedals/tech/cleats with that re-launch.

FSA PowerBOX SC
Single sided meter on their own crank. Inconsistent power data. Pass.

ZWatt Zpider
It had problems. Nobody watched that video, so let’s not dwell on this one. Next.

ArcRayo 
External gauges placed on an Shimano R8100 in a dual sided configuration. Overall the numbers were close but there were inflated power numbers on the right side crank sensor causing it to report higher wattage than pedal power meter and smart trainer that I tested against. Outdoor testing showed a high variance in readings, possibly due to temperature drift. Only four data sets collected before I removed this from the bike.

Tempo
Single sided Shimano road crank using quite a large sensor/pod design. Reported a few % higher than a Gamin Rally RS100 (single sided) in testing. Uses a CR2450 battery (similar to Power2Max). No review completed.

Look X-Track (SPD)
Just not great. Accuracy issues among a few other things. Amusing side story – Look actually used an image of the Favero Assioma PRO MX pedal in the user manual for this product. I could not believe it when i saw it (and subsequently called them out on it). I have their road pedals here to test 12 months after this SPD review. Wish them luck!

Favero Assioma DUO/PRO
I really don’t have much to say on these. They’re the “Varia'” of power meters. They just work and people who have them, love them. They’re my go-to for most power meter and smart trainer testing. Some DUO-Shi had issues with the spindles that resulted in replacements being issued. I was never a fan of the DUO-Shi due to the q-factor increase, also for the bearing sleeve design and having to source your own pedal bodies to install. Thankfully the PRO RS is the solution with a standard road pedal q-factor, SPD-SL pedal body, and tipping the scales at under 250g. Favero offer replacement bearing kits, pedal bodies, upgrade kits, charge cables, and have a very useful companion app with support diagnostics, etc.

ok, what’d I miss?