Different power meter displays significantly lower watts

Hi All,

The title should give a pretty good hint at my question. The powermeter that I’ve been using for years started to have some issues. I’m sending it back to be looked at. In the interim, I’m using another powermeter I have. It’s a different brand with different chainrings, but everything else is the same.

Over the weekend I noticed that my average power, normalize power, etc. seemed low on the rides I was doing. Today I did an interval workout and my watts seemed about 10% lower. By this, I mean that the effort felt the same and my HR was roughly the same as previous workouts. However, it was nearly impossible to hit my target watts. It seemed my output was about 10% lower.

With that said, I’m not sure what the best option is. If everything else feels the same, I’m assuming it’s a powermeter difference. I have access to WK05, so is there something I can use in there to help? My other thought is to do a field test on this powermeter and use that FTP to adjust my zones.

(I did look into calibration for this powermeter, but the internet seemed to say I’m SOL)

Any thoughts or opinions are welcome. I will be with this powermeter for the near future as my guess is I’ll have to replace the other one and I’m not sure when I’ll be able to fo that.

Welcome to the forum @edm5001! That can be a common problem with different power meters. If you are going to be with this one for the near future, a field test can definitely help you to make some zone adjustments. If you’re pretty confident with your HR and perception of effort, you can probably “eyeball” your new zones based on your power meter readings on different ride lengths and intensities. I’m sure you’ll be very close. I would minimally do a threshold workout and a LSD ride using HR to set the effort, and then analyze the files post-ride to estimate the changes to your existing zones.

Do a series of max effort intervals over various durations over several days using the new PM, compare the values to similar efforts with the original PM, adjust training zones as appropriate. When you get your original PM back, repeat the process.

Thanks. This all makes sense.

Luckily I’m taking a break from racing, so my training is flexible. Going to use these next few days to do some efforts, have some fun and then play around with the numbers :+1:

Hi there, more a WKO/Trainingpeaks follow up question more than anything else, but what about regularly using different power meters and performance data.

I have an Infocrank, a Quarq and an Inspider, which all measure power slightly differently and I probably train pretty equally with them all over the course of a season.

Is there a way to ‘normalise’ the data, if I could say try and benchmark them all against my indoor trainer? I understand it could be more difficult than just an offset of X watts but it surely would make sense to have them broadly aligned? Or should I not sweat it if they are ± 5% from eachother? Especially given Z5/6 work.


@edm5001 all great suggestions so far.

The only thing I would add is that if you are going back to the other meter (and it is the same after getting repaired) you could use fit file tools online to correct your current power meter so that the calculations in wko5 are the same.

Or as @ryan suggested do a new test and change tryout zoning during this time so all calcs are relative to the new meter.

On 4iiii, P2M and Favero power meters there is a Power Scaling Factor which enables you to match the reported power to another meter. I assume however that yours doesn’t have this feature.