Difference in TSS between inside and outside endurance rides

Why is there so big difference in time for the same TSS inside / outside?
Let’s take Town Hill for example. It’s 129 TSS, same intensity. But inside it’s 2:45, outside — 4:07.
With TP load for outside ride in this case is around 218. Almost extra 100.
Is everything correct here?

I dont use TP so I’m not sure what you mean about TP load being higher. TR lists the TSS as the same for indoor and outdoor variants of Town Hill.

This topic has been discussed numerous times on the forum and the TR blog has also addressed it,

See the FAQ at the bottom of the page

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TR lists the TSS as the same for indoor and outdoor variants of Town Hill.

Right, and it’s the question that I’d like to clarify. I understand that time could be different, this is fine and I can understand it. But why TSS is the same is not clear. I did shortened version today with 3 hours instead of 4:07. And ride TSS is 159 (vs 129 in Town Hill). If I would ride 4 hours plus, it would be more obviously.
I think that formula for TSS should be more or less the same (otherwise result would be different between different systems and it doesn’t make sense). And I don’t get why it should be different for indoors / outdoors.

I think the TSS of 129 for Town Hill is a typo - it should be 192. The indoor variant is around 70% FTP for 2.75 hours : 70 x 2.75 = 192.

The outdoor variant looks odd - if you completed it as prescribed, it would be a 271 TSS ride. The outdoor workouts FAQ says that “To account for these external factors, many TrainerRoad outside workout equivalents will be between 15 and 60 minutes longer (depending on TR workout length) to ensure you are getting the same training benefit while riding outside.” So in this case, if you have a clear road without traffic, stop signs etc, then the outdoor variant would actually give you 40% more TSS than the indoor.

sounds like your FTP is not the same on TR and TP. Fix that and the TSS for each ride will match up (maybe not exactly, but within a couple TSS points say 127 vs 129).

Yes, maybe an FTP discrepancy across TR and TP - but the indoor variant of Town Hill cannot be a 129 TSS workout … it’s 0.69 IF for 2.75 hours, so it must be at least 190 TSS.

TrainerRoad:

“Rough Duplicate” of Town Hill on TrainingPeaks:

TSS looks about the same to me.

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Yeah, my bad - though 1 hr at FTP is 100 TSS, because TSS is based on Normalised Power (not average), then a workout at 70% FTP will be scored proportionally less…

I still think the outdoor variant of Town Hill assumes you’ll be massively less productive (for riding outside) than the indoor variant. Seems like it would depend a lot on your local roads.

TSS = time * IF squared, fellas.

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Sounds like a better explanation could be provided for what the expectation is. Is it posted in the outside workout notes?

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