Dual Power Source Ramp Test

Equipment
,
1

Hi friends,
I’ve known about a significant power differential between my Powertap P1 (left only) power pedal and my Elite Direto trainer for awhile, and for today’s ramp test I decided to run both separately. My methodology was probably not ideal: I paired the power meter to my Garmin and hit the lap button for each step of the ramp (that cognitive load is worth a few extra watts, right?). I forgot to hit it at the most crucial moment near the end of the test, but Garmin Connect says my Max Average 1 min power from the power meter was 423 W (18:34-19:33) vs. just 368 W (18:28-19:27) on the Direto. 58 watts is a massive difference!

TR gave me a new FTP of 276, which is a 12-watt increase since my last Direto-only ramp test 3 months ago. Taking 75% of my max minute with the power meter gives me 317, a 17 watts up from my last Powertap-only ramp test 6 weeks ago.

Calibrated both power sources during the warmup.

The photos show the steps for each file from Strava for comparison.

I guess I’m just asking for general insights on this disparity. I have no idea which is more accurate. Based on riding with others, I kind of suspect the truth is somewhere in the middle, but that might be wishful thinking. Moving forward I plan to use the Direto power indoors and the Powertap outdoors, just making the 13% adjustment to my targets.

Screen Shot 2021-02-16 at 7.28.45 AM
Screen Shot 2021-02-16 at 7.28.45 AM1046×523 58.7 KB

Screen Shot 2021-02-16 at 8.56.46 AM
Screen Shot 2021-02-16 at 8.56.46 AM1010×523 62.1 KB

1 Like
2

Why not use the pedals full time with power match? Indoor and outdoor power is the same then. This is what I do with my Vector 3S pedals and Kickr 2018. Works great.

3 Likes
3

I have done that, but it’s nice to keep the power pedal on my main outdoor bike rather than swapping all the time. It just takes a minute but it’s an extra step.

4

I’d also advocate using Powermatch. My Elite Turbo Muin reads too high at lower power and too low at higher power. Using my Rotor LT I know it’s consistent both indoors and out!

1 Like
5

“It just takes a minute” and your problems are solved. :wink:

1 Like
6

Yes been there done that. I have P1S and Elite Zumo around 30W difference

If you email elite they will ask you to record a power test on their app and eventually give you a file to download and update your trainer so that the trainer curve matches better to your pedals.

This improved things a lot for me but not enough to be confident in the trainer, I switched to use it PML linking the pedals to the trainer. Powermatch in the TrainerRoad app is another option.

There a few threads if you search Zumo and PML.

1 Like