Magene PES P505/P515 Power Meter Crankset - ±1% Accuracy, 625g Lightweight, 330H Battery, 110BCD, ANT+/Bluetooth, IPX7 Waterproof for Cycling

4mo update. I’ve tested this against my Favero pedals, Kickr and power is dead on with the other power sources, I’ve also had zero issues or drops. This powermeter is amazing, best value out thereI switched from a Quarq to this and I’m blown away at how good it is. Power matches my 2 Quarqs perfectly. Zero offset is stable with no drift.The only recommendation I have is to pay close attention to the install instructions, while it looks like a standard shimano crank install there are 3 specific steps for tightening down the crankset that need to be followed closley

Let me first admit, mine is not a typical usage of this product.I'm 64 and I put a moderate 15-minute spin on my exercise bike every other day, just to "clear the cobwebs". The bike is a 25-year-old felt-pad-resistance type and I keep it on a covered outdoor patio. The problem I encountered is: It's anybody's guess how much work I'm putting out from one workout to the next. Am I doing better? Am I getting worse? The actual resistance is dependent not only on the tension knob but also the weather conditions, the inherent inaccuracy (backlash) of the tension mechanism itself, whether the felt pads are damp, how far pads have heated up from my peddling so far, etc. I want to do a consistent caloric output (or wattage output) on every workout.So I decided to get this metering crank. The nice thing about this is it doesn't matter if your bike cost $5000 or $5, is stationary or road, this measures output at the crank via an internal strain sensor.My exercise bike had a standard (aka Ashtabula, American) bottom bracket (BB), so before I could install this thing I had to do a two-phase BB conversion. Phase one goes from Ashtabula to Euro (aka BSC, BC, ISO, British) See "Black Ops BB Conversion Kit American to Euro", which is essentially just a pair of internally threaded bushings. Phase two goes from Euro to PF41 (aka BB86, PF24, Shimano 24mm) using the Shimano BB-MT801 kit. Look on YouTube if you need your hand held doing either of these.Since my exercise bike had 1/2 thread pedals, I also had to buy a new set. This crank uses standard 5/8 thread pedals.UPDATE: It seems I sold myself short. After months of using this crank and witnessing my performance actually decline, I was a bit incredulous. So I tried the OneLapFit "zero calibration" function for my crank (which I probably should have done immediately after installing). Now my new normal continuous NP power reports as 121W. Take that you young whipper-snappers.Oh, and I also had to get a 4-arm chain ring with 52 teeth and a 110 BCD. The 52 teeth matches my bike's original chain ring, which lacked the bolt holes.The documentation is really sparse. The assy diagrams are good, but there's no text, just pictures. I suppose they're trying to be universal. What do the LEDs mean during charging? Where do I go and download the app? No mention.I'm not a bike mechanic and have never worked on bikes, but the hardware installation went smoothly. Just be aware that most of the parts are dedicated right or left and have right or left hand threads. Don't go forcing anything. Watching the YouTube vids before you assemble is a must.Also, unless you're an enthusiast, you probably won't know this: In order to get a summary of your workout, like I do, you will need a bike computer. Not wanting to do a week of research on what was the best computer to get, I just went with the Magene C406 --which ended up working fine. See my separate product review of that.So now I can report that I can do 45W average power output for 15 minutes and moderate effort, with a 42 cadence, and pretty good left/right balance. That's nothing to be proud of, but probably OK for age 64.UPDATE:

Works great. Good measuring. Sometime connection losses.

I received it yesterday , i have Scott addict with shimano 105 drivetrain . My bike mechanic installed it for me without any problems , he used the original shimano chainrings . I charged the meter , downloaded the app and requested the code several times without receiving a response . Finally i checked the junk mail folder and found the code. After a few attempts the app found the power meter . I took it on one ride , it updated quite rapidly , I hit 400 watts going up hills but only for a few seconds before i started to slow down . Now i will ride the watts to keep my rides intense . I also have a very accurate estimate of the calories burned . So far I love it . I will be updating . Too bad I can’t figure out how to get a few extra charging cords . I may have to call Magene .Magene responded to my email with a link showing where to buy extra charging cables, I ordered 2 for my piece of mind , it will be shipped from china . I think they should ship the power meter with an extra charging cable .I did my second ride today with the power meter , it functioned flawlessly , it updated quickly , it showed 100-150 watts on level roads , 250-300 watts with the slightest hills . My Cyclemeter app paired easily with the power meter , it shows that battery level is still 100% after 2 rides . The power meter paired easily with my Garmin edge 830 , I created a data screen showing watts and cadence , along with radar and wind data . I hate clutter . So far so good .

This was extremely easy to install, took me around 20 minutes. So hard I have had zero issues with the product. I switched over my own 105 chainrings to this, which went on with zero issue. This is one of the cheapest powermeters you can buy, but still is more accurate than shimanos.