Segment Calculator Explained

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Accuracy hints first:

Strava errs by doing the following:

1) truncates distances which means that .4 mile will be shown for .41, .42 ... thru .49, so the distance shown can be off as much as .1 mile

2) guesses at watts based on GPS position which you may have noticed can be off by so much it shows you rode on a totally different road

3) can only know your cadence if reported by a sensor/head set on your bike

4) ignores your wheel size while averaging speed based on GPS (see 2 above)

5) uses an algorithm to smooth segment timing results so that a half dozen people can be shown as having the exact same time

Solution is to use your own on-bicycle

True power meter (preferably 2 pedal based), speed sensor, and cadence counter then analyze with a PC based software such as Saris PowerAgent
 

Before reading below try at least once the free online Power to Weight Calculator which automatically calculates your power to weight, speed per watts, and Race Category based on power.

Make up some numbers, doesn't matter, won't hurt a thing.   

Caveat: Only part of the story is told by Watts (whether on the flats or climbing) so be sure to review: Torque.

Anybody with a true interest in sport will arrive here with the confidence that they can certainly figure out how to throw, catch, bat, and run.

All they have to do is be placed in the ballpark, and that is just what this calculator does.

It puts you in the cycling performance ballpark.

The calculator strips away all the fuss and muss of having to log elements that only address meaningless minimal correction factors (such as skewer weight) as is the case with most other calculators.

Those questionable inclusions are done at best because of feature creep and at worst because of the desire to sell you more products.

In line with that orientation you might find it useful to adopt my own policy with regard to weight.

I exclusively use my morning bare bones weight on the bathroom scale.

Doing that allows me to keep a baseline through all purchases of lighter faster equipment.

Power meters are not so precise anyway, though much better than all other alternatives.

In a world of wildly divergent data it pays to keep things simple.

Users of Strava quickly realize how often they can be shown as having ridden on a completely different road or course.

However, the long standing segment leader times on most boards can still be assumed to represent a fairly high level of human performance... cheating aside.

As for the Strava Segment Calculator, I rushed posting it for Widder's use while fine tuning it by rearranging the following formula used by the  Power to Weight Calculator:

double speed = System.Math.Sqrt((2* watts)/(9.8067*85*.0053)+.185)*60*60/1000*0.621371192*rideEfficiency;

Solving for watts instead of speed is now complete (08/31/18), and the preliminary results show it to be quite accurate... as far as rules of thumb go.

Otherwise, be sure to keep in mind what the great Jocelyn Linscott said, "Strava is always drunk."

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