Power & Speed Seems Incorrect - Signal Hill

OK, I had a ride and didn’t do much drafting at all. I calibrated my power meter before hand. My speed generally seems too high for the power especially on the segment Signal Hill, it seems miles out, this is a 9% gradient so not much drafting effect there. . Here are some examples from Strava. I have added my weight to Zwift which is 190lbs

Signal Hill 9% 314w - speed 15.2mph.
My bike calculator app shows 7.3mph on drops.

Signal Hill 9% 152w - speed 8.5mph.
Bike calculator shows 3.6mph

I did multiple laps and the speed on this segment seems way too high.


yeah that does seem high… hell it’s double = not good. What kind of powermeter ?

Stages power meter, works fine generally. It’s not like there is a descent before the hill etc…if you want to add me on Strava ‘Stephen Whiteley - Preston, UK’ you can take a look at the data, most of the time it seems right but that segment seems well out!

This ride has about 10 others on it, they all seem way too high for a 9% https://www.strava.com/activities/259832397

if you look at that segment… it’s not all 9%… most of it is much less
(signal hill segment)

You are right Johnny - it never actually reaches 9% so don’t know how it is a 9% climb! so somehow it is incorrectly labelled in Strava or in Zwift


Yes, that is a Strava glitch, I’ve seen that happen on real-life segments as well. If you look at the profile on the slider that appears when you highlight the segment, the elevation change appears to be 62 feet, while the segment reports an elevation change of 152 feet. On a .3 mile segment, that’s a pretty big discrepancy.