PowerTap 2.4 Setup Zero's + Q's



RidwarePhil

New Member
Oct 23, 2006
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Hi Recently took delivery of a PowerTap SL 2.4.

I connected it up and all seems to work well so far. I have a few questions about the setup stages.


1) Computer Setup 3 lets you decide if zeros are included in the averages.

1) Watts
2) Speed
3) Cadence
4) Auto zero function.

What do you recommend is it better to include zeros initially and then knock them out in the software.

2) I havent installed the PT software yet is it worth it or should I go straight to Cycling peaks WKO+

If so are there any lniks to the optimium setup of Cycling Peaks?

3) On my first ride out I was a little surprised that I wasnt getting heart rate readings displayed. Reading the manual it seems that either power or HR can be displayed and not both simultaneously?

Is this correct?

I know I should focus on Power and not HR but I have een training with HR for the last few year and would like to know what it is even if just for reference.

Cheers Phil
 
The only three reasons I can think of for displaying non-zero average power (NZAP) on your PT CPU are:

(i) as a proxy for Normalised Power (NP). Note however that any such correlation between NZAP and NP is just a spurious one and does not have any mathematical basis. It also depends on the type of riding you do and the type of rider you are. But some riders have found NZAP to match NP quite well in certain circumstances.

(ii) in cyclocross when you use HR to keep the CPU timer going when running but only want the avg power when riding

(iii) for whatever reason, you still want to know what your final NZAP was, only download directly into Cycling Peaks (CP) and would rather not have to export the data to Excel or Polar files to work it out since CP doesn't calculate NZAP.


NZ Speed makes no sense to me, since the clock timer already stops when you do.

NZ Cadence may be helpful in the sense of knowing how fast you pedal only when you are pedalling and can remove, for example, long coasting descents from the equation.

Auto zero? Is that torque auto zero - leave it on unless riding a fixed gear.

I'm no longer familiar with latest PT software but CP is the best out there. Go here:
http://www.cyclingpeakssoftware.com/

Not sure if 2.4 CPU displays differently to the Pro/SL CPU but I thought HR was an option on the bottom line of the display, while power is shown on the top line of the display?
 
Alex Simmons said:
Not sure if 2.4 CPU displays differently to the Pro/SL CPU but I thought HR was an option on the bottom line of the display, while power is shown on the top line of the display?

No it doesn't display differently.

should you want to, you can view power and HR at the same time. (you may need to get the computer to 'find' both power and HR)

ric
 
Thanks Alex and Rick for replying,

Alex - Sorry I am being a little thick are you therefore suggesting that I eliminate zeros from the power data by default and use data with zeros eliminated (ZAP) for display purposes on the CPU.

Speed data seems obvious that zeros should be taken out anyway.

Cadence I can see the benefits of NZ Cadence


Rick - I will go and get the CPU to find the HR strap.


Anybody have any info on setting up the CP software (options etc) or is it really obvious?

Cheers Phil
 
Setup of Cyclingpeaks will be about as obvious as you can get.

I think Alex was being politically correct and rather than coming out and telling you that non-zero average power is all but useless, he was giving you the one example where it would be useful.

If you use cyclingpeaks (or calculate it yourself elsewhere), the best value on power to tell you how hard you worked (taking into account rest periods on zero power, but also giving weight to harder efforts), normalized power is what you're looking for. If you don't use cyclingpeaks or calculate normalized power, non-zero average power MAY correlate for you, but then again it may not. You won't know for sure unless you also calculate normalized power which brings us right back to using that instead.
 
RidwarePhil said:
Alex - Sorry I am being a little thick are you therefore suggesting that I eliminate zeros from the power data by default and use data with zeros eliminated (ZAP) for display purposes on the CPU.

Anybody have any info on setting up the CP software (options etc) or is it really obvious?
1. No

2. Install is easy and it has a bunch of default chart settings. These are all highly customisable once you set it up.
 
Alex Simmons said:
The only three reasons I can think of for displaying non-zero average power (NZAP) on your PT CPU are:

Not sure if 2.4 CPU displays differently to the Pro/SL CPU but I thought HR was an option on the bottom line of the display, while power is shown on the top line of the display?
Yes, you can display HR and power at the same time with an SL head, in the same way you can with yours, by the sound of it. That's how I use mine.