TSS estimated on calender incorrect

I think there is an issue with the TSS estimation calculator when inputting a manual entry in the calender. As you increase the time, the TSS per hour reduces for the same effort ie. 1 hour easy is 36 TSS therefore, you would think 2 hours would be 72 TSS and 10 hours would be 360 TSS but it is not. It shows as 67 for 2 hours and 260 for 10 hours. This shows the calculations are wrong and are only exacerbated the longer the exercise period. A case in point, once you get to 36 hours plus it estimates TSS as a minus figure.


Wanted to add one more thing to comment above.
TR ‘gives’ the estimate of 100 TSS for All-out effort (scale 10) for 1h bike activity

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Hi there TR :slight_smile:

Is there any particular reason of this non-linear relationship between TSS value and the duration?

Thank you!

That’s simply part of the formula. I’ll try my best to explain this one, but it’s a little tricky so bear with me!

A 3-hour ride at “race pace” cannot be completed as fast as a 1-hour “race pace” ride. The non-linear relationship between TSS and Duration is a function of how the longer you go, the “harder” it is at a slower pace.

For example, 1 hour at race pace (RPE 9) is 90 TSS, but 3 hours at RPE 2 is still 98 TSS. It might not be as extreme of a ride, but it’s just as hard. To put it in other words, your TSS/hour is lower but it feels hard because you rode for three hours.

The negative TSS issue on rides past 36 hours is a bug, we’ll get that fixed soon (hopefully before anyone needs to estimate TSS on a ride that long :wink: ).

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Larry, thank you for your answer. I get that one about the feeling ’ harder’ as the times goes by, because of the fatigue, but what about the short activities like 5min Level 10. I see an 8TSS/5min (rate of 96TSS/h)?


I was just about to raise a bug on exactly what you mentioned. I was sketching out my plan leading up to Paris-Brest-Paris (1200km to be completed in 80-90h) in August '19 and discovered I would have a circa -5000 TSS. Had to set the intensity as custom with a 0 TSS to be able to save it.