Feet Ascended Variation

[PaulSB]

Yesterday a friend and I rode a hilly 57 mile circular which included Great Dun Fell.

My figures using a Wahoo Elemnt are 57.24 miles and 5315 feet of ascent. My friend recorded 57.19 and 6122 feet using a Wahoo Bolt. Obviously the very slight mileage difference is irrelevant but how can two devices vary so widely in relation to ascent? Would this suggest one of the devices needs to be recalibrated?

Riding with friends I'm used to the idea our feet ascended will vary but this is a 17% variation. I'm satisfied with the accuracy of my Wahoo but based only one reason. A few months ago I took part in a challenge where feet climbed was important. The challenge relied on individuals honestly reporting their figures. Out of interest I recorded my effort on my Wahoo, my Vivoactive HR and Strava using my phone. The results came back with a variation of 47 feet across all three devices. Rightly or wrongly this suggests to me the results I'm getting are accurate.

 

[Deleted member 26715]

My own thoughts are that these devices are not particularly accurate, my rides invariably start & finish at the same place. Therefore my logic is that my elevation gain should always match my elevation loss, very rarely does this happen. What happens if you allow Strava to correct the elevation of both rides?

 

[PaulSB]

@Phaeton - thnkas, this is interesting. I've done the correction, which I've never done before, and my ascent now shows at 6023 and increase of 708. Out of interest I went back through my August rides and corrected those as well. Added 5000+ feet to my yearly total. In two instances on rides which involved serious climbing my ascent increased by +1000 on each.

From this do I assume the Wahoo is inherently inaccurate despite having checked it on one ride against two other devices - a watch and a Strava app on phone?

 

[NorthernDave]

It's not just Wahoo - my Garmin 810 can vary considerably on different rides on the same route and on more than one occasion has recorded me cycling along below sea level on a road that very clearly isn't.

 

[Pale Rider]

My own thoughts are that these devices are not particularly accurate,

I have compared elevation figures on group rides a couple of times.

The various devices used by the riders recorded wildly differing figures.

At best, only one of those devices from each ride could have been accurate.

If I recall, my Garmin recorded different elevation figures for the same ride, but I've long since stopped bothering with it.

 

[Venod]

I don't know how Strava works out its elevation, but I sometimes do a downhill ride at the end of a turbo session as a cooldown, sometimes Strava will report this reasonably correctley at other times it will record all my downhill as ft gained, I did 17 miles down the Galibier and recorded over 8000 ft of climbing, on normal undulating courses it usually matches the film I am riding.

 

[Deleted member 26715]

I noticed this the other day, a friend & his son went for a ride, I think they both use phones on Strava to record (he certainly uses an iPhone), they started at the same place & ended at the same place, but the rides were hugely different.

 

[Sharky]

This is an interesting read:-
https://support.wahoofitness.com/hc...Seeing-Elevation-Differences-in-My-Ride-Data-

 

[ColinJ]

It isn't even possible to get exact elevation figures using OS maps. Roads are often not exactly where they appear to be on the map because OS adjust the layout slightly to make it more legible. Example...

Landranger scale (1:50,000)...

Explorer scale (1:25,000):

You can see how far apart the green and red tracks are despite both being plotted exactly along the road at the respective scales...

I marked the same point in both cases and the software finds a difference in elevation of 7 metres!

I chose the road deliberately because it runs along the brow of the steep-sided Calder Valley. A few metres lateral difference is the difference between being on the top road or the climb up to it!

I assume that the Explorer map is more accurate than the Landranger, but who knows?!

 

[PaulSB]

The elevation adjustment thing in Strava is new and interesting to me. Yesterday's ride increased to 6023 which is roughly on par with my companion.

I've now adjusted all my 2020 rides** and gained 24,714 on my climbing total.

** pretty quick to do in the app.

 

[Pale Rider]

the steep-sided Calder Valley

It certainly is.

I recall one shortish beast of climb which you took us up on a forum ride.

I only just made the top on the ebike.

Predictably, I couldn't catch Carrie, but I think even she was working fairly hard.