dumb TSS question

postal_bag said:

I've read somewhere on this forum that TSS is IF squared, times duration (in minutes) divided by 60, times 100. Is this wrong?

Right. Another way of looking at it is IF squared times duration (in hours) times 100. Minutes divided by 60 equals hours so the two formulas are the same.

postal_bag said:

In the book, TARWAPM😉 the formula is: TSS=(s x W x IF)/(FTP x 3600)

What do the "s" and "W" stand for?

I had to think about this for a minute.

s = seconds (which when divided by 3600 = hours)
W must be the normalized power for the duration of concern.

W/FTP = NP/FTP = IF, so that boils the formula down to:

TSS = ( IF x IF x seconds ) / 3600

but then that's not right because we're off by a factor of 100. Is there a typo in your post or in the book?

postal_bag said:

I've read somewhere on this forum that TSS is IF squared, times duration (in minutes) divided by 60, times 100. Is this wrong?

That's correct: TSS = IF^2*100/hours

Quoted post said:

In the book, TARWAPM😉 the formula is: TSS=(s x W x IF)/(FTP x 3600)

What do the "s" and "W" stand for?

Well just backing it out from the formula above: s = time in seconds (s/3600 = time in hours), which means W must be NP*100 since NP*100/FTP = IF*100 which makes the two formulas identical. Actually checking page 128 in the book, W = NP in watts so it looks like there's a factor of 100 misplaced somewhere.

Methinks it's a typo in the book and the formula on page 127 should read:
TSS = (s*NP*IF)/(FTP*36) or just give the other version:TSS = IF^2*s/36
I don't see why the term W was introduced when NP was defined a few pages earlier.

-Dave

Looks like you beat me to the punch Steve 🙂

Yeap,
Definetly a typo in the book on the factor. This was confirmed at the Power seminars and by others on this forum.

Should be in the FACTS sticky link if we ever get one 😉

daveryanwyoming said:

so it looks like there's a factor of 100 misplaced somewhere.

There's a typo in the book.

Edit: oops, should have read the whole thread.

Steve_B said:

Right. Another way of looking at it is IF squared times duration (in hours) times 100. Minutes divided by 60 equals hours so the two formulas are the same.

I had to think about this for a minute.

s = seconds (which when divided by 3600 = hours)
W must be the normalized power for the duration of concern.

W/FTP = NP/FTP = IF, so that boils the formula down to:

TSS = ( IF x IF x seconds ) / 3600

but then that's not right because we're off by a factor of 100. Is there a typo in your post or in the book?