Strava's calorie reading way off?

[cobbwheels]

At first I thought Strava is under-estimating the power I make and calories I burn in my rides. I don't use power meter but I've entered all the weights and bike type the best I could.

However, Strava doesn't have an option for a fully loaded tour bike with pannier bags nor what you're wearing on a ride. I enter my bike's loaded weight.....BUT I don't think Strava accounts for the drag of the pannier bags, full fenders, and the loose, casual style sports wear I prefer to wear than body-fitting suits. It might even be assuming I'm using GP5000 tires or the fastest rolling gravel tires available but I don't and I'm using slow, cheap, and heavy puncture-proof urban tires. And typical with tour bikes, MTB style rims with lots of spokes. I'm probably at the maximum drag configuration short, of actually wearing a parachute... So I've always assumed Strava would certainly under-estimate calorie estimates.

That is until I compared my calorie readings against the average TdF riders do on an average stage distance. And my calorie reading per distance is 7% higher. And, if I consider body weight as well, in terms of calories per distance per kilo of body weight, the figure becomes 9.3% above average as I only weigh 120 lbs. I thought that's crazy. If I had actually been riding in the least drag configuration, the estimates would even be a lot higher I suppose.

 

[Mr. Beanz]

I can never figure it out in our case. Only thing I figure is I'm heavier than my buddy, it causes me to burn more.

I outweigh my buddy by 80 pounds. We do a 4,000 ft climb, I keep up with him and at times beat him up the climb.

He's a calorie counter getting frustrated because I've burned more. I don't care myself but he often brings it up trying to figure it out.

I figure both are posted on strava so numbers must be equal even if not accurate.

 

[cobbwheels]

I can never figure it out in our case. ***Only thing I figure is I'm heavier than my buddy, it causes me to burn more***.

I outweigh my buddy by 80 pounds. We do a 4,000 ft climb, I keep up with him and at times beat him up the climb.

He's a calorie counter getting frustrated because I've burned more. I don't care myself but he often brings it up trying to figure it out.

I figure both are posted on strava so numbers must be equal even if not accurate.

You're correct and that's 100% expected, you're heavier so you'll burn more calories.

'Potential Energy' (including estimated calories burned) in a climb is calculated by Mass (your body weight) x Earth's gravitational field x elevation gained. That's ignoring friction and drag.

Therefore, the greater the body weight, the more calories you'll burn in a climb. Simple physics. I find it odd your buddy seems to expect otherwise, unless his bike is >80 lbs heavier than yours!

 

[cobbwheels]

My dilemma on the other hand is stronger influenced by aero drag due to mostly flat terrain I had these strava readings.

I wear casual dry fit clothing and my bike has permanently attached bags and many other 'fred' stuff because I only have one bike for every possible utility including recreation. The bike is heavy and the drag is obscenely high. I doubt Strava knows that so it must be underestimating my calories and yet the calories I'm seeing is above average per distance compared to TdF pros do on average during a race and is significantly higher if body weight is considered as well.

I don't really care much about calories for the sake of nutrition or dieting. My BMI is already gobsmack low. I'm just borderline underweight and even lower than the leanest pro cyclist in TdF.

 

[Mr. Beanz]

You're correct and that's 100% expected, you're heavier so you'll burn more calories.

'Potential Energy' (including estimated calories burned) in a climb is calculated by Mass (your body weight) x Earth's gravitational field x elevation gained. That's ignoring friction and drag.

Therefore, the greater the body weight, the more calories you'll burn in a climb. Simple physics. I find it odd your buddy seems to expect otherwise, unless his bike is >80 lbs heavier than yours!

Yeah, I've explained my suspicions several times but he thinks he should be equal in calorie burning.

And his bike is much lighter than mine being smaller, 54 vs my 58. And lighter carbon wheels.

I as well don't count calories at all. Heck, I'm an eater ha ha ha.

 

[cobbwheels]

Yeah, I've explained my suspicions several times but he thinks he should be equal in calorie burning.

And his bike is much lighter than mine being smaller, 54 vs my 58. And lighter carbon wheels.

I as well don't count calories at all. Heck, I'm an eater ha ha ha.

He desperately needs tutoring about reality!

I think he's confusing calories with perceived effort. Definitely not how you compute calories on a climb. Sure, perceived effort will have an effect on calories burned, but not as big as total riding weight.

 

[cyclintom]

Strava simply doesn't have the information necessary to calculate the correct caloric losses.. Always treat it as an approximation.

 

[cobbwheels]

Strava simply doesn't have the information necessary to calculate the correct caloric losses.. Always treat it as an approximation.

I wondered if others are getting better / closer estimates. Strava doesn't have inputs for things that could affect aerodynamics for example like fenders, racks, and pannier bags, and also the kit you're wearing or even the type of helmet or other drag sources like the tires.

Apart from that, we are not given the information what equipment assumptions they make those calculations.

I wish it did. I don't think it would be that hard to make drag approximations according to various layouts. They just need to gather data from testing various setups and then use table lookups on their app. Equipment selection can be via dropdown list so the user doesn't need to type anything apart from their weights. Why can't they do that?

 

[PelotonPete]

Hey! I totally get where you're coming from. Strava's calculations don't take into account all the factors that affect aerodynamics in road cycling. It would be great if they included inputs for things like fenders, racks, and even the kit and gear we wear. I agree that gathering data from testing different setups would help improve their approximations. Would love to see more detailed drag calculations in the future!