AeroPod, PowerPod and Newton

I have a gravel bike and a road bike and have been trying (for years, really) to get a PP to properly calibrate with both. Never succeeded with my PP BLE, which eventually stopped working. Upgraded to the newest PP a couple of months ago. One bike (the gravel bike) seems close, but the road bike is reading consistently higher than my effort. What's the best way for me to get to an accurate power number on both bikes?

So far I've done some cal rides, then edited the profiles to have the correct values for weight, tires, and road surface. The gravel bike (Trek Crockett) has 700x43 (which is 1.7", and not a value present in the profiles), and the road bike (Cannondale Synapse) has 700x25. (BTW, I wonder about the CRR assumptions with wider tires; it seems that the program assumes wider tires and lower pressure are always slower, but that's not the current wisdom).

I tried to check calibration on the last road ride on the Synapse. It would have lowered the power, but I couldn't send the profile because the Fric and Tilt were out of range. Help appreciated, Thanks -- Matt

Your road bike has an excessively high Car--it should be around 0.0054. This will result in lower watts.

However, your ride file shows that your mounting angle has changed significantly since calibration. The PP figures out this change, but when you try to use Check Calibration to fix things, some of the parameters are out of bounds.

I have modified your road bike profile with the correct Crr. Load this into your road bike profile.

Your gravel bike shows a lot of angle changes for the mount. Either your unit is rotating during the ride, or you will need to lockout your front fork.

Thanks for the tips -- I'll try the new profile.

The gravel bike has a Redshift shockstop suspension stem that has a tiny bit of travel -- they call it an "effective travel of up to 20mm." It takes the sting out of the bumps. The PP is on an out-front mount, so that might magnify any movement. Do you think that's enough to produce the variation you saw? I don't think it's moving otherwise -- I really crank it down with with a screwdriver when I put it on. I suppose there's also some travel from the relatively large and soft tires.

Maybe I'll try the bar mount and see if that improves the numbers.

Matt

It's possible the shock stop is affecting things.