FTP test questions

CptKernow

"Estimated average power" is what I'm talking about. Not sure if this is normalised / weighted from the actual power estimates.

Either way I find it to be around what I'd expect from other set ups I use...

AK_jnr

Nope. Its miles out. Like a good few miles.

AK_jnr

I did a little test this morning. I stuck strava on in my back pocket and then had the garmin record the power.
1 hour ride, plenty of ups and downs, barely any flat road so a good test. A consistent pace with 3 peak power efforts thrown in. Only a couple of stops for lights as well.

Actual average power from my PM - 221

Strava estimated power - 207

It was closer than I remember so I am happy to be proved a bit wrong on this ride!

Obviously longer rides with longer efforts and more stopping and starting might be a bit different.

supermurph09

AK_jnr wrote:

I did a little test this morning. I stuck strava on in my back pocket and then had the garmin record the power.
1 hour ride, plenty of ups and downs, barely any flat road so a good test. A consistent pace with 3 peak power efforts thrown in. Only a couple of stops for lights as well.

Actual average power from my PM - 221

Strava estimated power - 207

It was closer than I remember so I am happy to be proved a bit wrong on this ride!

Obviously longer rides with longer efforts and more stopping and starting might be a bit different.

14W is still about 7% out, that's still quite a difference imo.

CptKernow

Supermurph09 wrote:

14W is still about 7% out, that's still quite a difference imo.

+/-7% vs £500+ for +/-3% - I can live with that.
If it is consistent (which I can't vouch for) then at the least it provides a usable benchmark.

bobmcstuff

Think the problem (or one of the problems) with Strava's estimate is it doesn't account for things like drafting, headwinds etc. isn't it. Same as the problems with estimating pro's w/kg from timing climbs...

Alex_Simmons/RST

CptKernow wrote:

Supermurph09 wrote:

14W is still about 7% out, that's still quite a difference imo.

+/-7% vs £500+ for +/-3% - I can live with that.
If it is consistent (which I can't vouch for) then at the least it provides a usable benchmark.

Well it was 7% out for this ride (on average). What about on another day with more / less wind, etc etc? It hasn't answered the question of whether it's a useful benchmark.

Consider that the typical variance in one power output ability during a season is only ~10% you'll see why nailing it down a little more tightly helps.

Cheapest (i.e. free) benchmark that is going to provide reasonable repeatability is steepish hill climb speed, provided the wind is light.

okgo

https://www.strava.com/segments/1112955?filter=overall

Look at 4th, 8th and 10th and tell me Strava average power is worth paying ANY attention to.

sloppyschleckonds

okgo wrote:

https://www.strava.com/segments/1112955?filter=overall

Look at 4th, 8th and 10th and tell me Strava average power is worth paying ANY attention to.

I guess the lads around there don't like riding on feel much

dyrlac

okgo wrote:

https://www.strava.com/segments/1112955?filter=overall

Look at 4th, 8th and 10th and tell me Strava average power is worth paying ANY attention to.

This looks like a bang-on accurate demonstration of the impact of aero on an out and back course. Strava's power estimate is essentially based on rider + bike weight plus speed over the known gradient. At the kinds of speeds you chaps are riding, it's not surprising that an aero position gives you 150 - 200 "free" watts.

LanterneRouge010

I would definitely do an outdoor FTP test if you are going to be training outdoors as that will give you the appropriate power zones. I did the test two days ago and made a vid on how to analyse the numbers: https://www.youtube.com/watch?v=-ZtP_f9BPcI