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Climbing power vs flats power

Posted: Wed Oct 11, 2017 9:34 pm
by Bugsbunny
Hi John

My PP outdoor riding climbing power numbers seem to align quite well with my perceived effort from my TACX NEO powermeter.

But when I ride on flats (assume now not drafting) the power numbers from my PP seem to be relatively higher than the perceived efforts on flats from the TACX Neo. (For example, my best 5/10/20min efforts recorded in my Strava power curves all come when I'm riding outside on flats - as opposed to climbing).

What is the best way to fine tune my outdoor riding on flats power?

Bugs

Re: Climbing power vs flats power

Posted: Thu Oct 12, 2017 6:37 am
by Velocomp
Please post a .ibr ride file and we will take a look.

Re: Climbing power vs flats power

Posted: Sat Oct 14, 2017 2:46 am
by Bugsbunny
Thank you John

https://www.dropbox.com/s/0d6y8l3h6u8wx ... 5.ibr?dl=0

Three hill repeats then an section of flat out and back. No drafting.

Re: Climbing power vs flats power

Posted: Sat Oct 14, 2017 6:41 am
by Velocomp
There is no cadence data in your ride file, but you do have a cadence sensor ID. Check the operation of your cadence sensor.

You have a nice style on your hill repeats; very consistent watts!

On the flats your bike speed varies, as well as your watts. You are not as consistent in your riding style.

I don't see anything wrong with your profile settings and your watts readings are reasonable.

I would try riding at a constant pace on the flats, so that you can get a "feel" for the effort required over an extended period of time. I believe the PP numbers; remember, the TACX is doing a simulation of outdoor riding...

Re: Climbing power vs flats power

Posted: Sun Oct 15, 2017 10:04 pm
by Bugsbunny
Thanks so much John.

I know I wasn't very consistent on the flat bits as I was just playing around with a few sprints. :-)
There was something wrong with my cadence sensor as it usually works.

When I was choosing the IBR files, I was also thinking what type of ride makes for a good one for you to check and had some trouble to find one.

Should I pick one with little wind, no drafting, something with an O/B section, a comparison between climbing and flats, and also one where I hadn't moved the PP from the front mount around or...

Do you mind if I provide another IBR file if you let me know what type of ride would be best for you?

Bugs

Re: Climbing power vs flats power

Posted: Fri Oct 20, 2017 1:03 pm
by Velocomp
The best rides are little wind, out and back, no drafting, not too long (so that wind conditions don't change).

Re: Climbing power vs flats power

Posted: Mon Oct 23, 2017 8:55 am
by brookside
I have exactly the same issue with my Newton vs DFPMs, climbing power matches nicely but power on flats or gentler slopes is too high on Newton. After a lot of experimentation I found the iBike suggested CdA (.4) was too high. I lowered it to 0.26, along with a minor change of lowering the Crr to .0036, and now flats and climbing are consistent between DFPM and Newton, either cruising segments, FTP or VO2max intervals; and overall average power, NP and TSS is also pretty close for the entire ride. Don't be afraid to jack the CdA way down.