Power meter for Vendetta

[Lief]

Rick,
My QRings are set on OCP3 - took me a while to figure out what was going on back when I first got these.
My memory** was that it came set on 3, I moved it to 4, then moved back to 3.
either that or...
it came set on 2 and I moved it to 3 (and never moved it back).




**when I married my wife I lost my ability to remember things like this - since she remembers everything my abilities atrophied.

 

[ratz]

My QRings are set on OCP3 - took me a while to figure out what was going on back when I first got these.
My memory** was that it came set on 3, I moved it to 4, then moved back to 3.
either that or...
it came set on 2 and I moved it to 3 (and never moved it back).

Oh goodie you have one of the fun cranks where the bolt is under the arm.
I was surprised to see that your dimpled holes worked correctly on that style crank exactly on the bolt used for diamond frames that is completely unexpected. Perhaps correct but.... Since you don't seem to have the same experience as the rest of us let me ask the leading questions.

1) If you Adjust your ring so that the "2 dimpled" hole is on that bolt.
2) Then if you put your foot on the pedal and fully extend your right leg.
3) Do you then find that the at the top of the ring; the last Chain link that is engaged exactly lines up with the "1 dimple" hole.

If that's not the case you can't use any of the factory dimpled holes. Instead you have to unbolt the ring and rotate it so that "1 dimple" is the first one engaged; then mark the hole under your crank arm on that bolt as your new personal custom "2 dimple" hole. Then you use that one to count off the distance to your new personal 4, 1,3,5.

OCP 1 is special it marks the deadest/flatest point of the ring which is used to figure how to orient the ring to find the real OCP 2. Basically a double purpose hole which seem to confuse everyone.

I'm taking the time to point this out because during the testing last night I can tell you that I found OCP4 the best for me; then OCP 1, and finally OCP2. OCP 3 and OCP5 where basically un-rideable for me. That tells me that subtle offset make a big difference in performance and comfort.

This is all based on the attached document.

 

[Rick Youngblood]

That throws a curve ball into figuring this out. It does appear Lief's Q-rings are rotated a few degrees counter clockwise from mine and Bob's, hard to eyeball, but it does seem considerable.

Edit: Would like to add, that because I see that Lief's Q-ring is set different than mine, does not in no way mean his is set wrong, or that I'm saying his is wrong. According to Rotor, individual recumbent riders dead spot differ, therefore this would cause a different start setting.

 

[Rick Youngblood]

Testing completed. I have the raw data now I just need to go analyze it. Files attached; if using them remember to look by "Time" not distance when graphing.

Bob, looking at your Strava data, I see OCP#4 to be a keeper compared to the other setting, correct?

 

[LarryOz]

Regular Q-rings testing complete: My conclusions and spreadsheet at the bottom if you don't want to read all of this
Here are my 2 tcx files from my "Reegular" Q-rings power testing comparing the power readings from my TrainerRoad program using KICKR for the power with my Garmin file using Vector Pedals for Power.
LarryOz Reg Q-r-ring p…in.tcx
https://www.dropbox.com/s/kf4fj8q2dlkjha3/LarryOz Reg Q-r-ring power from Garmin.tcx?dl=0
LarryOz Reg Q-r-ring p…KR.tcx
https://www.dropbox.com/s/mv2bclv69r56zug/LarryOz Reg Q-r-ring power from TR-KICKR.tcx?dl=0

You will need this information to decipher the data in the files.

Garmin Pedals calibrated first
10 minute warmup period to warmup the KICKR - spin down test done right before the 10 minute warmup ended
Each file contains all the data from OCP #1 - thru OCP #5, starting with OCP#1.
The plan:
30 second intervals pedaling at 70, 80, 90, 100, 100 rpm, first at 150 watts, then 200 watts, then 250 watts.
This protocol was repeated for each of the 5 OCP settings on the Q-rings.
I paused both devices: TrainerRoad workout, and Garmin head unit, as I got off the bike and moved each the Q-ring to each successive OCP reading.
In between each 30 second interval, I allowed a 30 second transition to attain the next cadence and/or power change.
The TrainerRoad program was in ERG mode, therefore the power readings from the TR program where very close to 150, 200, 250 respectively.
The protocol was as follows:
Q-rings at OCP#1
10 minute warmup
30 seconds at 150 watts at 70 rpm
30 seconds transition to 80 rpm
30 seconds at 150 watts at 80 rpm
30 seconds transition to 90 rpm
30 seconds at 150 watts at 90 rpm
30 seconds transition to 100 rpm
30 seconds at 150 watts at 100 rpm
30 seconds transition to 110 rpm
30 seconds at 150 watts at 110 rpm
..
30 seconds transition to 70 rpm at 200 watts
30 seconds at 200 watts at 70 rpm
30 seconds transition to 80 rpm
30 seconds at 200 watts at 80 rpm
30 seconds transition to 90 rpm
30 seconds at 200 watts at 90 rpm
30 seconds transition to 100 rpm
30 seconds at 200 watts at 100 rpm
30 seconds transition to 110 rpm
30 seconds at 200 watts at 110 rpm
..
30 seconds transition to 70 rpm at 250 watts
30 seconds at 250 watts at 70 rpm
30 seconds transition to 80 rpm
30 seconds at 250 watts at 80 rpm
30 seconds transition to 90 rpm
30 seconds at 250 watts at 90 rpm
30 seconds transition to 100 rpm
30 seconds at 250 watts at 100 rpm
30 seconds transition to 110 rpm
30 seconds at 250 watts at 110 rpm
30 seconds transition to next OCP #
..
paused both workouts - and OCP # changed to OCP#2 - restarted the workouts, finished 30 second transition - then repeat the entire 3-sets above
paused both workouts - and OCP # changed to OCP#3 - restarted the workouts, finished 30 second transition - then repeat the entire 3-sets above
paused both workouts - and OCP # changed to OCP#4 - restarted the workouts, finished 30 second transition - then repeat the entire 3-sets above
paused both workouts - and OCP # changed to OCP#5 - restarted the workouts, finished 30 second transition - then repeat the entire 3-sets above

Notes:
I also hit the "lap" button on my Garmin head unit at the start and the stop of each 30 second segment. That way all the lap average values are automatically calculated for me on the Garmin side.
Since I created the TrainerRoad program in 30 segments intervals, they are also recorded and average just like the laps are on the Garmin.
Unfortunately and unknown to me until now, TR did not separate all my data in the 150 watt range since it considered it "recovery" - All data still in tcs file, but when I look at TR data it leaves those out.
The key to deciphers the good 30 second segments from the "transition" segments is that they alternate from the beginning. The very first 30 second segment is the 150 watts at 70rpm on OCP#1, then they alternate after that.
If you get lost, another way to tell is look at the average rpm for each 30 second segment. The "good" one will be the one closer to the target rpm's of 70,80,90,100,110. This is because the transition segment immediatley before was me ramping up and trying to level off to the next rpm level, therefore it is a lot rather off of the next target rpm value.
...
See TR workout online: https://www.trainerroad.com/cycling/rides/1992181
See Garmin workout online: https://connect.garmin.com/modern/activity/756433123
..
My preliminary conclusions:
The Garmin power readings are always lower than the KICKR (although there appears to be a couple anomalous readings during the OCP#5 phase)
The difference appears to become greater (but not always, and not large) as the pedal rpm increases.
The difference also appears to become a little greater as the OCP# increases.
..
I am really eager to put the round chain rings on and repeat the test to see if the power readings are more inline between the 2 systems.
If they are not, then I may have to send one or both systems back to be re-calibrated at the factory.

SS of my spreadsheet data: I have 100rpm in bold as that is what I usually ride at so most pertinent to me. If you want the entire file, message or email me and I will send it to you.

 

[ratz]

Finish running the numbers finally

Based on the tests I'll be adjusting my Indoor trainer calculated FTP down 5% when using it on the road with the stages power meter.

The following isn't good science, it just a simple test and my lazy interpretation of it. Good enough for my needs for the next year. Unfortunately, Data recording Errors for OCP4 and the Round ring; mean that if you wanted hard science I'd need to re-run those tests which there won't be time for for several weeks. For my needs I got enough data to figure out my offset for road versus trainer, but not enough to say if the q-rings are the main source of the error. In the end I don't care what my absolute power numbers are; just that they are consistent ride over ride; and mappable from indoors to outdoors.

Any ways here is what we have:

The following are the numbers from Training Peaks which includes the warm up data; and an zeroes recorded due to transmission errors. Most of the "anomalous" data was in the warm and cool down sections. For sustained efforts these numbers would likely improve



Looking at Normalized Power (NP) and Average power across the five tests they seem pretty consistent, The stated error rate is +-2%. The Stages FAQ had estimated that the Q-rings would cause at negative 4-5% offset in the readings; for a projected range of -6% to -3%.

So what to make of the data.

First the stages did indeed seem to read about 3-6% low for normalized power versus the resistance trainer on the Q-ring runs with clean data. I'm not sure what to make of the round ring, it tested similar to the Q-ring, but the data (see below) did have a somewhat large dropout; not as bad as OCP4, but enough to throw the numbers off. I'll observe that my effort with the round ring was consistent with OCP5. For both the pedal stroke was sloppy because the phasing isn't good for me. I simply do not pedal as smooth on round rings any longer. So the variation on the Round might have been that I was pulse pedaling in a bad way especially for a left-only power meter. I'm going to discount that as not that interesting for my needs, you'll have to form your own conclusions; but I will likely go back and test that when there is time because I'm still curious.

So Back OCP 1, 2, 3 are the ones I pedal the smoothest (after we lose OCP4 to the bad data). Those efforts all are solid in the expected 4-5% range.

Looking at the Variability Index, the Stages is on par with Power Trainer so both sources give equally consistent numbers relative to themselves. All of the the runs with a VI of 1.1 were solid. The 1.23 for OC4 and the round ring at 1.13 wasn't quite as good both accounted for by the dropped data. Anything over 1.3 is considered poorly paced in my book and not what we should see for the trainer running in ERG mode; which force the pace to be completely steady.

In the end the OCP position does not seem to affect the stages. This is expected with the 1 time per revolution measuring; and the consistent VI and similarity in the power reading deltas seem to back that up.

Here are the rest of the graphs and the excel file with the data for anyone that wants to poke at it.

OCP varied on a give meter Zero removed.


OCP's compared across meters with intervals of zeros removed.

OCP varied on a give meter Zero Included.

OCP's compared across meters with Zeros

 

[ratz]

Grrrr my inner mathematician has been nagging me about the data errors and whether I was adjusting correctly in my head to account for the recording dropouts.

So of course someone pointed out that I can clean the data in Golden Chetah before putting it in training peaks for the calculations.

So...... Here's the Corrected data with the warm ups and cool downs stripped out so that the comparison data is much tighter and steady state.



And here's the data with the Zero recording dropouts removed.



That really cleans things up only the overage on OCP2 is an outlier (That was the one that lost the most data in the clean up by a large margin); and we can see that the Stages is reading 4-5% lower than the trainer and that there is no real difference between Round rings and Q-ring for accuracy on the Vendetta. Max power is still off but that's expected with a Left only meter and that can be flatted out in Golden Cheetah if doing hard core analysis.

I'm much happier seeing that from the cleaner data.




Updated spreadsheet attached; The time based ZERO data in the spreadsheet is still there it's just filtered out; the warm up and cool down was removed

 

[jond]

Some wives get flowers....

Mine.... Bike parts

View attachment 157

living the dream ratz

 

[LarryOz]

Ratz,
Thanks for your detailed analysis of all the Q-rings power data, and also Regular rings too.
It looks like we both ended up with "about" the same conclusion: That the KICKR appears to record a higher wattage output than "other" power meters.
My Vectors seem to be more off than your Stages, in the 7-9% lower range. I still might get the Wahoo "recalibration" loaner from Wahoo and see if it makes any difference.
There was a time when both KICKR and Vector "matched" up, so it is a little frustrating that it does not now. Maybe the Vectors are just reading low or they are really susceptible to how tightly they are "torqued" onto the cranks. (I see more testing for this theory)
Another piece of data that seems to jive with this is that is seems to me to take a little less power (watts) to reach equivalent speeds of 5-6 months ago. I'll have to spend some time analyzing data thought to prove it, and of course there are so many other variables that make each ride unique, especially ones outside, that it might be liek comparing apples to oranges.
Either way, in the end, I'll probably stick to the KICKR numbers for KICKR workouts since that is where I do the lion's share of my really intensive work. If I dropped the numbers down 10% or more, I would probably tend to not get as hard a workout.

 

[Lief]

that is where I do the lion's share of my really intensive work

Larry - after yet another 90 min on the trainer last night TRYING to maintain a hard workout - I don't know how you do it.
KICKR or whatever...it's just plain soul-sucking to ride a bike in place.

When I was out 'racing' with TimTurner last weekend I was maintaining 280 watts for more than a handful of minutes, HR at 170+, then kicking it over 400 for a burst to stay in front of him (I started with a healthy lead) at the end.

On the trainer, same bike/power/etc, I just can't seem to worry myself about anything over 155HR and 250W.

I honestly don't know how any normal can do it for extended periods of time - maybe I need to learn how to meditate while I'm riding?

 

[battleaxe0]

Walking Dead intervals. Ride normal til you hear or see a zombie, then all out til the danger is over. Good for 45 minutes if you zip the commercials

 

[ratz]

Walking Dead intervals. Ride normal til you hear or see a zombie, then all out til the danger is over. Good for 45 minutes if you zip the commercials

There's an app for that: https://itunes.apple.com/us/app/zombies-run!/id503519713?mt=8

 

[ratz]

Larry - after yet another 90 min on the trainer last night TRYING to maintain a hard workout - I don't know how you do it.
KICKR or whatever...it's just plain soul-sucking to ride a bike in place.

When I was out 'racing' with TimTurner last weekend I was maintaining 280 watts for more than a handful of minutes, HR at 170+, then kicking it over 400 for a burst to stay in front of him (I started with a healthy lead) at the end.

On the trainer, same bike/power/etc, I just can't seem to worry myself about anything over 155HR and 250W.

I honestly don't know how any normal can do it for extended periods of time - maybe I need to learn how to meditate while I'm riding?

There's an art to that. Larry's just extra ordinary.

My max on a mag trainer is about 1 hour then I'm bored stupid. For the KickR we break it up

• Structured hardworks <= 1 hr for specific target.

Gotta build those challenging and tight so you don't ever get a minute of down time to get bored or discouraged.​

• Good simulation rides for the endurance miles > 2hrs;

Best if you have matching video that has sceneray and good hills that make you want to hit it then it's easier to ride hard. add music; an audio book, or tv program and it goes pretty fast. I'm partial to audiobooks; mrs ratz watches back catalog scifi.
​

• 4 hours stuff.....

Get up at 5am and start so that I'm too dam tired to realized how bored I am.​

On the 4 hour stuff what I fine a challenge is the bike does not move side ways so you don't get that normal lateral movement that keeps the blood moving in places besides the legs. So after awhile it just get sore or tiring..

 

[Lief]

On the 4 hour stuff what I fine a challenge is the bike does not move side ways so you don't get that normal lateral movement that keeps the blood moving in places besides the legs. So after awhile it just get sore or tiring..

Hadn't thought about that aspect - but yeah, that's definitely part of it.

I'm thinking that trying to watch movies is just hard - maybe I'll try an audiobook.

 

[Lief]

maybe I'll try an audiobook.

Or maybe I'll just move to Redding CA, where Rick is, and always ride outside no matter what.

 

[Rick Youngblood]

Or maybe I'll just move to Redding CA, where Rick is, and always ride outside no matter what.

P L E A S E, someone with a Cruzbike move to Redding, I welcome all !

 

[battleaxe0]

P L E A S E, someone with a Cruzbike move to Redding, I welcome all !

Heh - only if you tow me up those mountains! I get tired going up an overpass.

 

[LarryOz]

Thanks Bob, Lief.
I have ridden the KICKR for 5+ hours just with the Wahoo app as my display - basically looking at wattage, HR, cadense. However I was listening to music.
There might be a little bit of art to it, but having a goal, a workout to follow, something to occupy the mind really helps a lot!
I also find I have greater motivation when I start earlier in the day - i.e. 5am or so. I have started later like 9am, and meaning to ride 5-6 hours, actually "talked" myself down to 4. Funny how your mind works sometimes!
It is also MUCH, MUCH easier to have a movie or an existing ride to watch while riding.
I will ride my really hard segments or workouts now watching my Sebring ride video or a video of a local ride with a lot a hills.
...
It is really helpful to have a goal. Now, the workouts are my goals. I find I can maintain a higher wattage, higher cadence, and higher HR on the trainer than the open road. Yeah, I guess I am weird in that part.
The other thing I really like about the trainer - is that you don't get a rest - the workout is harder and more intensive - there better for you in that you will bet stronger faster.
If only they will just come out with "virtual races" we can compete in.

 

[LarryOz]

Yeah, but make no mistake - I would also like to move to Redding too - Rick, maybe build some kind of bikers-bunkhouse nearby for us all.

 

[super slim]

Is there any power meters that could be glued to the curved inside or flat outside (If thin) of FSA Gossamer cranks that have been cut down to 153 mm.