Interval data power meter question

Papai_Adam · 9 January 2023 18:38

Hello!

If I enter to activity-interval data, I see this

But, I have an 175mm p2m ngeco. Why happening this?

Thank you

Adam

app4g · 10 January 2023 04:08

This is taken from your FIT file.(as is. I do not believe intervals.icu will do any processing to it. Just translate)
It’s just “shown” by intervals.

check your fit file and your headunit?

rolandplanitz · 10 January 2023 05:50

SAXONAR GmbH is the german company behind Power2Max so that part is correct.
Have you installed the app for power2max? maybe they default to 172.5mm cranks if nothing else is set.
Or better yet, the crank length probably comes from the bike computer / watch and not necessarily from the power meter itself. On my garmin edge I could set up the crank length in the power meter settings.

EDIT: if I remember correctly, my Wahoo ROAM V2 wouldn’t let me enter a crank length for my newly installed QUARQ Spider. The weather wasn’t nice enough though so I have yet to generate a fit file with that setup. I’ll come back to this on the weekend.

Cary_Blackburn · 10 January 2023 08:45

The same thing happens with mine (165mm P2M ngeco). I’m assuming the power reading is correct.

Cary_Blackburn · 10 January 2023 08:49

I’ve just sent a message to P2M support about this. Lets see what they come back with.

app4g · 10 January 2023 08:52

This is what’s written on the Assioma App. So head unit takes precedence

rolandplanitz · 10 January 2023 14:08

given that the P2M is a Spider Power Meter I don’t think the crank length matters in regard to power. From what I understand the crank length is only relevan when measuring at the crank itself (single or dual) or at the pedal (single or dual). The Spider already combines the whole power.

That’s the point why I spent almost 800 EUR on the QUARQ Spider Power Meter (and carbon cranks, as the rival are technically the same mount, but not supported) instead of the 200-ish left-only crank stuff that came out for the SRAM Rival.

Papai_Adam · 10 January 2023 18:19

Thank you everyone

Cary_Blackburn · 10 January 2023 18:32

Exactly what P2M support came back with.

rolandplanitz · 11 January 2023 04:48

So to sum it up for somebody finding this in the future:

Saxonar is the company behind Power2Max
Spider Based Power Meters don’t care about Crank Length as they already have the total power at the “core”
the crank length displayed on intervals comes from the fit file, which in turn means: the head unit (or watch) rather than the power meter.
if the head unit (wahoo?) doesn’t support setting the crank length for spider based power meters (as there is no use in doing so) Intervals.icu defaults to 172.5
- which in this case is irrelevant anyways

Everything right? @david?

app4g · 11 January 2023 06:10

Garmin:
This is a crank power meter (left) and it’s 170mm. So I think you’re right. It defaults to 172.5 (Garmin doesn’t provide a crank length option for crank based power meters, but they do for pedal based PMs)