Watts to Speed Question


(Clint Westhoff) #1

Since everyone, for now, is the exact same weight, on pretty much the same bikes, and on the same road under the same weather conditions I assume watts to speed conversions should be the same except for the impact of drafting.

But when I look at the Strava leaderboard number 19 put out an average of 294 watts for a lap but is being beaten by multiple people who put out less than or right around 200 watts. There a are multiple other examples of this too.

I saw comments about dropping in next to a friend impacting speed, so that might be it. But it did make me wonder if we could have a more detailed explanation of how speed is determined. How much impact will “power ups” like new wheels have on speed from power numbers? How is the benefit of drafting calculated?

I’ve only ridden once so far and my speed seems realistic based on power and the virtual conditions, but I was just hoping for further info on the theory that understanding what is going on leads to better feedback.


(Michael Wagner) #2

Yeah, that doesn’t make sense. Everyone is the same weight, so highest wattage should be at the top of the leaderboards. Definitely something weird with their speed calculations. I wonder if it has to do with who has a faster vs. slower computer?


(Shane Whitworth) #3

I would be really interested in understanding this as well. From what I currently understand, speed is based on power numbers. So whomever is putting out greater watts should technically be riding faster. I did my first ride last night and was riding at 330W and had a few riders blow by me and take off like bullets!!! They gained massive time on me in just a few minutes. Maybe I am just a weakling but they would have to be riding at 500W+ I would imagine to do that.


(> TheMatLife (RCC)) #4

Same thing here… did a few all out sprints at 1000w and looked up to see me being passed…