Training Stress Score (TSS) and FTP

So, I today I was fortunate enough to have my question below answered by the team. Thanks @Nate_Pearson, @chad and @Jonathan - 5* Podcast as ever:
​"Given I want to do a 50mile group ride at the weekend (variable pace & 180TSS) and do a x-fit session mid-week I only have time for 2 TR w/outs 60-75 mins per week. What 2 would you suggest?"
Due to the number of characters allowed I couldn’t state that my aim for next year is an early peak for the 174km Tour of Flanders sportive. However, I was really happy with the suggestions made on the Podcast to use a low volume plan with VO2 first then a sweet spot - at least until post-Christmas.
What really interested me was the comment that the 50mile ride TSS came as a surprise to the team.
Whilst the ride is always ridden fairly hard and averages c.21mph with 2750ft of climb my TSS average is c.180!! @Jonathan suggested my FTP may be too low - from a vanity perspective, I wish it was but my last Ramp came out at 280 - but I maintained the 288 as I know I’m lousy at the Ramp v the other FTP tests. I’m also confident in my Neo and Vector power readings.
I guess I’m just keen to know if this level of TSS is unusual in a 50mile / two and a half-hour ride and what other factors could enable me to feel ok after a ride that on paper from a TSS perspective looks very hard. @stevemz Is this another example of high fractional utilization?
Thanks in advance.

180TSS for a 50 mile/2.5hour group ride seems about right. I have several group rides that match that distance and time almost exactly.

This wouldn’t be an example of high fractional utilization, but rather how anaerobic short efforts can inflate TSS quickly, even at much lower kj/absolute work values.

Crazy example would be a track sprinter, who has a very low FTP (150w) but is doing a 1 min effort day, will rack up a crazy amount of TSS.

I am really behind on my podcast.

I have a 50mi ride I do on weekends, your speed is enviable.

My ride is 50mi/3255ft @ 211 TSS and 0.82 IF in 3:04 @ 16.5mph. I wish I could average 21mph. I need more power. The ride is not sprinty though, but more in the 5-10min power range.

we have some flat group rides that when ridden hard (wind, fast guys) my TSS is in 160-180 range for 2 to 2.5 hours.

As @stevemz said you can rack up TSS by doing short anaerobic efforts, here is a recent 2.75 hour solo upper endurance / low tempo ride with 10+ second sprints every 8 minutes:

Thanks guys. Really useful. And yes - it can get a bit sprinty up the inclines, taking a short sharp turn and often at the end!! All this sounds like it will ramp up the TSS.