Zwift Chat

[CXRAndy]

Super effort last night chaps. Great to watch the video Paul

Looking at Pete's results, significant jump in only a matter of a few months, full of golds. Martin too was amazing to hang in with much younger riders

 

[CXRAndy]

Made the switch to annual payments on Zwift .

 

[Peter Salt]

Made the switch to annual payments on Zwift .

Yup, same here.

 

[bridgy]

This new zMAP/zFTP categorisation system does seem to keep some riders in Cat B who would previously have been upgraded to Cat A based on the old 20 minute power system (based on looking at recent race results). Is that the general concensus - that it has made it harder to go up a category, or are there also lots of examples of people now being upgraded who would previously have stayed in the lower Cat?

 

[Peter Salt]

This new zMAP/zFTP categorisation system does seem to keep some riders in Cat B who would previously have been upgraded to Cat A based on the old 20 minute power system (based on looking at recent race results). Is that the general concensus - that it has made it harder to go up a category, or are there also lots of examples of people now being upgraded who would previously have stayed in the lower Cat?

I think both?

The cat limit was previously calculated based on 95% of your 20 minute power - for B it was 4.0W/kg, so you could effectively do 4.2W/kg for 20 minutes and be fine. Now it's set at 4.2W/kg, but for 30 minutes. So that bar has been effectively raised a little bit. On the other hand, they introduced the 5 minute power limit - and through that we no longer have people, in B, that do 6W/kg for 5 minutes but then stay under the radar because their 20 minutes is fine - I'm a big fan of that.

 

[bridgy]

I think both?

The cat limit was previously calculated based on 95% of your 20 minute power - for B it was 4.0W/kg, so you could effectively do 4.2W/kg for 20 minutes and be fine. Now it's set at 4.2W/kg, but for 30 minutes. So that bar has been effectively raised a little bit. On the other hand, they introduced the 5 minute power limit - and through that we no longer have people, in B, that do 6W/kg for 5 minutes but then stay under the radar because their 20 minutes is fine - I'm a big fan of that.

Where does it say there's a specific 5 minute power limit - I thought Zwift's formula for calculating zFTP was secret?

 

[steverob]

Where does it say there's a specific 5 minute power limit - I thought Zwift's formula for calculating zFTP was secret?

Originally Zwift said they took account of your whole power curve from 2 to 40 minutes, but it seems that they really only look at your 3, 5, 12 and 20 minute values and work out your zFTP from those four numbers.

This certainly seems to be the accepted theory on the Zwift Forums anyway - I'm not sure if it was ever officially announced by Zwift themselves; much more likely that the formula was worked out by someone else, got posted on the forums, people found it to be pretty accurate after testing it and Zwift have never denied that it is true, so that's good enough.

 

[bridgy]

I think both?

The cat limit was previously calculated based on 95% of your 20 minute power - for B it was 4.0W/kg, so you could effectively do 4.2W/kg for 20 minutes and be fine. Now it's set at 4.2W/kg, but for 30 minutes. So that bar has been effectively raised a little bit. On the other hand, they introduced the 5 minute power limit - and through that we no longer have people, in B, that do 6W/kg for 5 minutes but then stay under the radar because their 20 minutes is fine - I'm a big fan of that.

Just doing a bit of digging on this and it actually seems that sometimes increasing your 5 minute power can keep you in a lower category rather than putting you up (something to do with power curves - I don't really understand it).

And as for no longer having people in B that do 6w/kg for 5 minutes...https://zwiftpower.com/profile.php?z=2144949

 

[bridgy]

Originally Zwift said they took account of your whole power curve from 2 to 40 minutes, but it seems that they really only look at your 3, 5, 12 and 20 minute values and work out your zFTP from those four numbers.

This certainly seems to be the accepted theory on the Zwift Forums anyway - I'm not sure if it was ever officially announced by Zwift themselves; much more likely that the formula was worked out by someone else, got posted on the forums, people found it to be pretty accurate after testing it and Zwift have never denied that it is true, so that's good enough.

I just read that it started with the 5 minute power figure and doesn't use shorter power durations than that

 

[Norry1]

Made the switch to annual payments on Zwift .

Yep, me too.

 

[Peter Salt]

Just doing a bit of digging on this and it actually seems that sometimes increasing your 5 minute power can keep you in a lower category rather than putting you up (something to do with power curves - I don't really understand it).

And as for no longer having people in B that do 6w/kg for 5 minutes...https://zwiftpower.com/profile.php?z=2144949

These are my numbers:





So the zFTP appears to almost exactly align with 40-minute power. And the zMAP with 5-minute. It even says so in the descriptions. And I think the category is then calculated based on these two numbers. I think.

 

[steverob]

Interesting. My zMAP (293W) is only one watt different to my 5 minute power but my zFTP (251W) is somewhere between my 20 and 30 minute values (slightly nearer 30).

 

[bridgy]

These are my numbers:

View attachment 714267

View attachment 714268

So the zFTP appears to almost exactly align with 40-minute power. And the zMAP with 5-minute. It even says so in the descriptions. And I think the category is then calculated based on these two numbers. I think.

Well the zFTP is meant to be a calculation of what you can do for 40 minutes + but it's calculated by some algorithm based on various power numbers from 5 minutes upwards (I.e not just what your 40 minute power is). My zFTP is 13 watts lower than my 40 minute power and zMAP 6 watts lower than my 5 minute power.

The category is based on zFTP and zMAP yes, but how they get to those figures is more complicated. And as I said earlier for some people increasing your 5 minute power can actually lower your zFTP.

Wit that in mind and with the fact that 20 minute power is no longer directly responsible for categories it looks and seems like more people are staying in Cat B for longer than would have been the case before. Not saying that's necessarily bad, just different

 

[Legs]

Yep, me too.

Me too!

 

[bobinski]

You boys have way too much time 😀 No wonder we lag Europe on productivity