So I had a race a few weeks back, my first long race with significant climbing in it. My Wahoo Elemnt Bolt said it was 4k ft of climbing, but Strava recalculated it to be almost 3k feet.
Which is the most accurate over a 70 mile course? I figured the Wahoo would be more accurate than Strava, is this true?
Have another race coming up that says it has 3k feet of climbing (gravel) in 50 miles. 4k (Wahoo) in 70 miles about killed me, so I’m trying to decide if the 50 mile with 3k of climbing is maybe a bit too much to tackle.
The frustrating answer is neither! If I record a ride on my iPhone gps, it gives me one answer. Strava gives me a second. Trainer Road gives me a third. Google earth gives me a 4th. All different elevation data based off the same gpx file.
The best way is to ride a known longish hill, that just goes up (no up/downs), consult a reliable Topo map to determine the elevation gain, and then compare that to the various sources like strava, wahoo, etc. Whichever source is closer to what the Topo map says, use that source, and do so consistently.
Your cycling computer is probably more accurate than Strava. It will be able to detect the small nuances of the trail or undulations of the road using its barometer.
Elevation lookup is dependant on gps accuracy. No matter how good the basemap is (and Strava’s is very good), if your gps says your 20m to the left and that happens to be down a cliff your elevation will be off. Imagine this being repeated every second, which is how fast gps is sampled, and you can see how reported elevation can be off.
That is an edge case, speaking of which…
For your altimeter, moisture can be your enemy.
Anyhow, I think the question was if a 50m with 3k of climbing is too much based on your experience. IMHO, I think you’re more than fine! Unless the race organizer got that number from gps elevation. If that’s the case, it’s anybody guess!
Wahoo recently switched out my bolt as I was continually getting different elevation. Unit was out of warranty was very impressed they did it and now mine align very close.
I used to ride a lot of mountain routes in Taiwan.
In general, my Garmin 520 was always good with the elevation. I believe the element bolt also uses a barometric altimeter, so should be similar performance.
One thing that would always play havoc with elevation was the weather conditions - once water from wet roads starts to get into the altimeter port (a small hole on the Garmin 520) the elevation would normally go to shit.
Another thing that would play havoc with elevation data was pressing ‘elevation correction’ on strava. This would usually clean up the elevation profile based on the route, but at the same time reward you with a big chunk of ‘bonus’ elevation.
Something to add to the answers above - if you have a device with a barometric altitude sensor, trust that over the gps. And gps accuracy is worse measuring altitude than distance afaik (would need to look up the error). Plus we generally ride a lot more distance than altitude, so the relative error is much bigger.
I race MTB and am friends on Strava with my competition. When we all upload our races to Strava there are variations in elevation gain of 200 feet +/- for a 1:30:00 of racing and approximately 15-20 miles. Granted this is in the woods on singletrack, so I’d expect that. So the true elevation gain is anyone’s guess.
Changing weather conditions can also reek havoc on barometric altimeters.
My personal experience with Wahoo is that it typically under reports elevation gain. On bigger MTB rides, it’s not uncommon for me to have an extra 500-1000 ft descending than climbing. That’s not really possible when starting and finishing at the same spot…
One reason I sold my Elemnt was the inconsistency of elevation. Had a crit where there was a 10 ft difference in elevation throughout the race at the same locations. Within spec? Possibly but my new devices have typically shown a 2 ft difference.
I can confirm that. I live in a small island city in the SF Bay Area that is flat as a board; however, ELEMNT shows an elevation gain of 700’ when I ride around the area next to the SF Bay. Strava corrects it to approximately 100’.
I never trust elevation data. I’ve never had a consistent experience with any computer, and I’ve had several, where the recorded elevation data could be trusted. It’s probably +/- 25% accurate at best. I think this is just one of those things.
I would like to throw a wrinkle into this. I did a ride this past weekend where I was trying to simulate the distance and elevation gain of Leadville 100 on the Iceman Cometh course. It was for charity, so don’t tell me I’m dumb/crazy…I already know.
I was using the Everesting rules to do repeats on the small climbs (40-110 ft) to achieve the elevation gain of Columbine, Powerline, Kevins, etc. When doing to recons of all these climbs, I would do 15-30 repeats then load my ride into TrainerRoad. I would then sum the total elevation gain then divide by the number of repeats to get a good average. I then hedged each by a couple of feet and calculated how many repeats would be needed. Fast forward to the ride…
Having plenty of time on my hands to focus on my head unit (Wahoo Roam), I was noticing that it was only registering fractions of what I was expecting on some of the repeats. Some would be what I thought was correct. Others, it would only credit me for 3ft, 5ft, etc (when I was expecting 40, 60, etc.). Since the ride was for charity, I just kept going until I reached the 11k ft. However, it took me almost 2 more hours than I calculated based on my wattage pace. When the ride was done, I loaded it into TrainerRoad and Performance Analytics says I climbed 13,135ft!
Sorry for the length of the background story, but here is my question. I understand that Wahoo uses barometric altimeter. Since I was riding such short and steep climbs (some are 20%+), I can imagine that being thrown off over 20+ intervals in succession. What does TrainerRoad use for their elevation calc? GPS? It is the same GPX file from Wahoo so the base data should be the same. For what it’s worth, the mileage between the two was exactly on.
Has anyone else looked into this before I dive head first into this rabbit hole?
TrainerRoad elevation gained is always a bit high for me. My outside rides are uploaded from Garmin Connect. Don’t know what TrainerRoad uses for elevation calculation.
My wife experienced elevation discrepancy between her Roam and my Garmin. Wahoo support told her that she was within specs — +/- 400 ft per 10 miles. Not sure if that’s reasonable but it did not make her pleased.
Strava corrects it to approximately 100’. 
