Originally Posted by
WTBATS
In the ideal world i'd have timing strips setup so I can test every gear accurately. Unfortunately all I have is a simple computer. I could use the GPS to determine flying 200 times but the accuracy is far from decent. For now all I have to go off of is cadence.
I've never used a SRM before nor seen what the software is capable off. A few questions to those who own one:
- Is the software capable of specifying a duration to calculate power within that time span? e.g. I want to know what my 5s, 10s, 15s power is and where that occurred on the track.
- Can I also do the same with speed? Ask for it to find the highest average speed for a 5s, 10s, 15s range.
To answer your questions: Yes and yes.
Every 1/2 second the head unit records speed, cadence, torque, power, distance traveled, time, etc...
You cannot pinpoint your positions on the track using SRM/Powertap. But, you *can* trace backwards based on torque spikes and zeros. For example, everyone stops applying torque the split second they cross the finish line of a Flying 200M. From there you can "walk backwards" in the file just over 200M to create a section of your Flying 200M. For simplicity and consistancy, I select a 12" section of time leading up to when I stopped applying torque.
You can also see in the files when you are in the turns...your speed increases (long story). So, you know where you are on the track.
Here is a Flying 200M file from Giovanni Rey:
Green line = Power
Purple line = Speed
Blue line = Cadence
Black text = Distance in KM (only shown in section averages)
Black text at bottom is elapsed time
Power is a calulation of Torque and Cadence. So when Torque is zero, power is zero. Look for when he crossed the finish line.
Please note that this may not have been a 12.0" flying 200M. It is 1m42s and 12s slices of data.
Notice how section 5 of the graph is 12". Notice the averages of the other colored data points (speed, cadence, power). Notice the green power spike. That's when he jumped out of the saddle out of turn 4 and down the home straight on this 250M track. You can see his current speed and cadence when he jumped. From eyeballing it, it looks like he jumped out of the saddle at 26mph and 95RPM. using that I can calculate what chainring/cog he's using, but I'm tired right now
His averages:
Cad: 138rpm
Speed: 37.56mph
At the 200M start line:
Cad: around 145rpm
Speed: around 40mph (max of the entire effort)
At the finish line:
Cad: 130rpm
Speed: around 35mph
(software will give exact values. I'm going off of the screen shot of the software.)
This is how you analyze a 200M using SRM
much more data than a stopwatch can provide. The only thing that can improve this is video camera...and we all have cell phones that can do that for us.