Numbers too low downhill?

[trichter196]

Hi everyone,

I recently bought a Powerpod, but since I do not have any experience in riding with power I’m wondering if my numbers are correct. Especially in the downhill parts where my power regularly drops to zero even if I definitely feel a considerable resistance when pedaling.

On the uphill parts the numbers seem more reasonable to me, maybe even a bit high. So I wondered if maybe something is wrong with my configured CdA, since this would be a big factor in the downhills, but negligible in the uphills, right? So I took a look into my profile and the value for CdA there is 0,351 which appears rather low to me, since I’m riding a MTB (on the tracked ride I was only riding on roads). Maybe I did something wrong during the initial setup? There was no option for MTB and since English is not my mother tongue I was a little uncertain what to pick.

Or maybe the numbers are off because I had my son with me on the ride in an iBert (front mounted seat). I accounted for this by adding his and the seats weight in the Powerpod profile. Would this mess with the estimated power? Although I also experience the same when going downhill without him (and without the extra weight added to the profile).

Or maybe the numbers are not off at all and I just suck at throwing down some wattage downhill?

Maybe someone could take a look at my attached file and see if something is off there? Just so you know: since my power regularly dropped to zero when pedaling downhill I simply stopped pedaling when going downhill at a certain point oft the ride, so I am mainly interested in the part aroud km 4-5. Also around km 20-21 my power was mainly zero, though my cadence was around 90 and my heart rate even increased.

Thanks in advance!

[trichter196]

Any help on this would really be greatly appreciated!

[Velocomp]

I'm seeing some variation in your slope correction. This might be because you have your son in a front seat; this would tend to exaggerate the effects of bike angle changes on uphills and downhills.

I agree your CdA is low; it should be around 0.49. I fixed this in the attached profile.

A higher CdA will also increase watts while on downhills.

Finally, make sure your suspension is on lockout. This could have a big influence on things.