How many Watts?

amaferanga

I did an FTP test about a month ago and got quite a surprising number. I'm planning on repeating soon on the same bit of road, but unfortunately I had a full week off the bike then a couple of gentle weeks following a crash so I have a feeling my FTP may have dropped a little (the test came after a solid block of L4 and mostly L5 intervals).

Anyway, I won't actually say the number I got, but the average gradient for the bit of road in question was 2.58% and I averaged 29km/h. It was a fairly windless day. I rode on the hoods the whole way. I weigh 68kg. Bike weighs about 8kg. Road surface was a combination of good and terrible.

What would be a reasonable range for the average power required? I've already tried the kreuzotter calculator.

I've no reason to suspect a calibration anomaly with my PowerTap, but I can't help but wonder.

okgo

How long was the test?

Would it not be vastly easier to ask what the figure is then we can match it to rides on similar terrain we've done (although not I as I weigh more, but others) and that should make it a little easier to see if its about right?

amaferanga

20 minutes. I thought I'd withhold the figure so as not to influence people's responses.

If it helps though, 345W.

danowat

FTP is power over 60mins, not 20.....

345w for a CP20 is pretty good, at the sharp end of the results for a 10 mile TT

amaferanga

danowat wrote:

FTP is power over 60mins, not 20.....

345w for a CP20 is pretty good, at the sharp end of the results for a 10 mile TT

FFS I know that.

danowat

"I did an FTP test"

"how long was the test"

"20 mins"

FFS? Your post could easily be mis-construed, no need to get your panties in a bunch.

W/kg would give you a better representation of the level, rather than raw watts.

cookiemonster

I reckon danowat was pointing out that its not the number itself thats suprising (like 700w would be ); but the fact that you're suprised suggests its a substantial improvement from what you've seen before?

How does it stack up against your 5 min power?

jon

danowat

5.5w/kg for FTP would put you into domestic pro territory............(but we already know its not FTP...)

375w for 20mins = 356w FTP (375 x 95%)

68kg = 5.23w/kg = Cat 1 / Domestic pro

jibberjim

It seems within a possible ballpark speed for those conditions to me, I'd expect to go faster on any test I'd do at similar watts, but I don't test in the same way and stay in my compete position etc. But it could be +/- 15% for sure depending on your actual aerodynamics.

Danowat I've done 365 for a 10mile TT (at 74kg), and I'm not not at the sharp end of 10mile TT results - peoples aerodynamics can differ massively, even with seemingly similar equipment.

danowat

jibberjim wrote:

Danowat I've done 365 for a 10mile TT (at 74kg), and I'm not not at the sharp end of 10mile TT results - peoples aerodynamics can differ massively, even with seemingly similar equipment.

Indeed, pacing and conditions would also have a bearing, but a well paced ride, in decent conditions with 365w would be "up there"

okgo

What have you done before? Does it seem much higher?

Is that average power or normalized?

It does seem high for your weight, and the speed does seem low, but other than that I remember reading you were a 3rd cat? Or is that wrong? As those figs should really see you quite well in any area of racing...

springtide9

It doesn't seem surprising to me.. but I wasn't convinced on my FTavar on the road bike).
I know you are much lighter than me.. but based on your avatar, you look much younger and fitter!

But maybe both of our PT's are not reading accurately.

BTW, what does Strava quote for the power figures? (can you remove the power data from the training file, upload and leave Stava calculate the figures?)

Alex_Simmons/RST

amaferanga wrote:

20 minutes. I thought I'd withhold the figure so as not to influence people's responses.

If it helps though, 345W.

That would require a headwind of 6km/h and with CdA ~ 0.35m^2. Crr of 0.005.
No wind and you'd be ~ 295W

P_Tucker

amaferanga wrote:

I did an FTP test about a month ago and got quite a surprising number. I'm planning on repeating soon on the same bit of road, but unfortunately I had a full week off the bike then a couple of gentle weeks following a crash so I have a feeling my FTP may have dropped a little (the test came after a solid block of L4 and mostly L5 intervals).

Anyway, I won't actually say the number I got, but the average gradient for the bit of road in question was 2.58% and I averaged 29km/h. It was a fairly windless day. I rode on the hoods the whole way. I weigh 68kg. Bike weighs about 8kg. Road surface was a combination of good and terrible.

What would be a reasonable range for the average power required? I've already tried the kreuzotter calculator.

I've no reason to suspect a calibration anomaly with my PowerTap, but I can't help but wonder.

We've all done rides where for some unknown reason power was significantly higher than you'd expect, and I for one never know whether I was on a spectacular day or my powertap was having a spaz. If its massively out of line with previous results which it must be else you wouldn't have posted, then you should know whether you've been doing the right amount of training to cause such a leap. If you haven't, then powermeter spaz seems likely.

amaferanga

Ok. Danowat - the reason I got my knickers in a twist is that having been posting on power related threads on here for over 2 years I'd have hoped to have shown that I'm not completely clueless when it comes to training with power and at least know what FTP is. So my apologies for the hissy fit

Where do you get this 5.5W/kg though? ~320W @ 68kg is only 4.7W/kg. I've since dropped a kg (the only good thing about 3 weeks of not training was that weight loss was pretty easy) so ~4.8W/kg. That's probably good 2nd Cat (what I am), not-very-competitive 1st Cat territory.

What made me question the 20min average (constant effort so NP was ~ the same anyway) was that it was more than I thought I'd be able to do - previous to that my 10min best (last season) wasn't much more than that (though I've had NP for 20min periods that have been higher). I'm just getting back after the injury, but my last few race results and the power numbers from them would suggest that an FTP of around 320W isn't far off. It had been fairly stagnant at no more than 310W for the early season, but I guess the L5 work I was doing actually worked.

I cycle part of the road that I tested on almost every day and I know that there's no way I only averaged 295W so perhaps there was some wind. A 6km/h headwind would seem like just about no wind anyway so it's not inconceivable that there could have been some headwind since I was heading west.

So I probably (hopefully) just had a good day.

jibberjim

amaferanga wrote:

A 6km/h headwind would seem like just about no wind anyway so it's not inconceivable that there could have been some headwind since I was heading west.

A 6km/h headwind feels like a gale if you're actually seeing it on a bike, remember the headline windspeeds you hear on the news are taken 10m up in clear air, what you see on the ground is broken up wind by the uneven ground, trees etc. etc. If you ride right on a coast path, or in completely flat land then headline windspeeds that you would think nothing of in the UK are massively noticeable.

However the 0.35 CA for sat up on the hoods is quite likely to be on the low side.

amaferanga

Fair point. I don't remember it being particularly windy. I wasn't trying to hold an aero position as speed was irrelevant for the test. The bike calculator I used assumed a CdA of 0.4826 m**2 for hoods position and Crr of 0.0033 - that gave a speed that matched my speed for the measured power pretty closely.

danowat

amaferanga wrote:

Ok. Danowat - the reason I got my knickers in a twist is that having been posting on power related threads on here for over 2 years I'd have hoped to have shown that I'm not completely clueless when it comes to training with power and at least know what FTP is. So my apologies for the hissy fit

Where do you get this 5.5W/kg though? ~320W @ 68kg is only 4.7W/kg. I've since dropped a kg (the only good thing about 3 weeks of not training was that weight loss was pretty easy) so ~4.8W/kg. That's probably good 2nd Cat (what I am), not-very-competitive 1st Cat territory.

Don't assume everyone knows you, or follows your postings.

And yes, my start figure was wrong (375 when it should have been 345) so disregard my post.