AeroPod, PowerPod and Newton

I recently bought a Powerpod after doing MUCHO research for my first power meter. All others didn't fit my use case--for a multitude of reasons. I was initially sceptical thinking that the P-pod couldn't be a "real" power meter, but DCR's review and John Hamman's (and others) remarks in the comments portion of DCR's blog, convinced me it was worth a try.

It's up and running, but being a complete novice, I've got a lot to learn.

I've done two rides of 40-45 miles with the meter. I've got it paired to a Garmin Edge 500 as well as a Garmin Forerunner 920XT. First ride the numbers were WILDLY divergent between the two devices and the 920XT seemed to drop out after the first part of the ride.

Second ride the two Garmin's recorded very similar (if not identical) data. Only thing I've noticed is that at the beginning of the 2nd ride the first 10-15 minutes were recording very, very high numbers, before settling down into a power range that seems more realistic. I only have my power numbers from my Computrainer session experience for a subjective feel for what is correct or not though.

I seem to remember reading somewhere that if the Powerpod isn't attached to the bike in the exact same position as it was in the test ride, you'll get wonky results at the beginning of a ride until the device figures out what's up, so that may be the case here.

I really don't have any other specific questions or comments, but am interested in pointers, if there are any, on how to proceed in learning how to use the P-pod and power in general. My next step is to figure out how to upload ride files into the Newton software and see what I can see there.

I'm really impressed with the device so far. To my novice way of thinking, it somehow makes TOTAL SENSE to approach this measurment problem indirectly, so to speak. It just seems a much more elegant way to do it, considering Sir Isaac's third law! For sure it opens the way to a much simpler manufacturing, installation and maintenance method. Yay, math!

STP

In the 1st 8 minutes the PP does a calibration when it is not attached the same way as the ride before.
My experience: If you don't climb in this 8 minutes the power values are too high.

We appreciate the comments.

Speedracer is correct that the PP needs to be mounted at EXACTLY the same angle for each ride; if it isn't then it will recalibrate itself during the first 8 minutes of riding. It does not make any difference if you're climbing or not during the first 8 minutes; the recalibration process is the same.

In my own riding I take a bit of care before each ride, making sure that rotate the PP (gently) forward, until it hits the stops of the metal mount. Then, I tighten it into position. My results are then pretty consistent during the first 8 minutes of each ride.

Velocomp wrote:It does not make any difference if you're climbing or not during the first 8 minutes; the recalibration process is the same.

I noticed that the recalibration values differ from the profile you ride during the calibration. I live in the middle of a hill. When I start upwards the values are more or less ok (around 300W for light climbing) but if I go descent with light pedaling I get 400W + values.
Therefore I had the impression that wind matters for the high values during calibration. But doesn't matter after the 8 minutes everything is fine.

speedracer wrote:

Velocomp wrote:It does not make any difference if you're climbing or not during the first 8 minutes; the recalibration process is the same.

I noticed that the recalibration values differ from the profile you ride during the calibration. I live in the middle of a hill. When I start upwards the values are more or less ok (around 300W for light climbing) but if I go descent with light pedaling I get 400W + values.
Therefore I had the impression that wind matters for the high values during calibration. But doesn't matter after the 8 minutes everything is fine.

What happens to you in descents during the first 8 minutes is entirely reasonable. Until the slope sensor is dialed in (8 minutes) the favorable force of downhill gravity is not precisely balanced by the opposing force of wind. At the high speeds of downhills you might get wacky watts until the 8 minutes has passed.

OP here.

I did another ride on Saturday and did not remove the Powerpod from the bike in between rides--so position should not have changed.

First ~10 minutes of ride still showed very high numbers before settling down. Same thing seemed to happen when I had to re-start the Powerpod after a coffee break towards the end of the ride. Bike was just parked at the coffee shop so no removal, but power numbers were crazy high at re-start. Is there anything I'm doing wrong? The Powerpod is firmly attached to the bike and I'm 99% sure it isn't getting moved around. Also, at the beginning of a ride, would it help to just turn the Powerpod on and ride around warming up for 8 minutes or so and then start the head unit(s) recording?

And do these first 8 minutes really matter much on a 2-3 hour ride?

TIA.

STP

It sounds like, for whatever reason, your original 5 minute ride did not get the right calibration constant stored internally. So, when starting a new ride (which includes riding after a rest break) your PP spends the first 8 minutes correcting things.

Here is what I recommend:

1) Load the attached factory profile into Isaac using the "Edit/Edit Profiles/Import" command

2) Attach your PP to Isaac. In the Edit Profiles window select the profile you just imported, then in the same window click the "Send to Device" command to load the profile into your PP

3) Disconnect PP from Isaac and click its button. The light should be solid Red, indicating that a new setup is required

4) Pair your PP to your ANT+ sensors, then do a 5 minute ride. This will correct the calibration constant, after which things should be OK.

Velocomp wrote:It sounds like, for whatever reason, your original 5 minute ride did not get the right calibration constant stored internally. So, when starting a new ride (which includes riding after a rest break) your PP spends the first 8 minutes correcting things.

Here is what I recommend:

1) Load the attached factory profile into Isaac using the "Edit/Edit Profiles/Import" command

2) Attach your PP to Isaac. In the Edit Profiles window select the profile you just imported, then in the same window click the "Send to Device" command to load the profile into your PP

3) Disconnect PP from Isaac and click its button. The light should be solid Red, indicating that a new setup is required

4) Pair your PP to your ANT+ sensors, then do a 5 minute ride. This will correct the calibration constant, after which things should be OK.

Thanks, John. Will do this ASAP. I did have some confusion when I first did my pairing and calibration ride so that might have screwed things up somehow. I'll make sure I understand this procedure and follow it carefully this time. A couple of riding buddies are very interested in the Powerpod now too!

STP

After resetting things please post a ride file.

Sorry for the long delay---shortly after my last post I broke my arm and have been off the bike while that healed.

Today I followed instructions and loaded the standard profile and recalibrated the Powerpod. I did a 1-hour ride and things looked good. We'll see how it goes and I'll report back.

My question today has to do with having a difficult time in tightening the Powerpod on its bracket. I simply could not tighten the thumbscrew enough to prevent the pod from moving about 1/4 inch back and forth. I ended up using a pair of vise-grips to tighten it down for my ride, but that can't be correct, right? Any suggestions on how to handle this?

Also, just to be sure, the correct procedure is to push the Powerpod all the way FORWARD in the mount?

TIA.

STP

Hmm...are you using a Velocomp mount?

This amount of tightening should not be necessary.

Velocomp wrote:Hmm...are you using a Velocomp mount?

This amount of tightening should not be necessary.

Hi John,

Yes--it's the mount that came with the unit which I purchased from Clever Training. Is there any chance they substituted something else?

I just pulled the Powerpod and the mount off the bike to inspect.

I did have my bike tuned up and new cables and bar tape put on while I was laid up so there's a chance (although I forgot to check this first) that the mechanic put the mount on backwards--with the flat side on the inside, which would make it difficult to cinch the mount up on the PP since you'd be losing a lot of leverage with the threads on the "wrong" side.

I tried hand-tightening the PP to the bottom half of the mount, but with no success. Then I used a pair of Vise-Grips to squeeze the mount tabs together a bit in order to get a little tighter fit from the get-go. That seems to have helped a bit, although it still takes all my hand strength to get the PP to stop pivoting in the mount.

I agree that it should not be this hard, but I can't see anything wrong or really anything that could be wrong except for stripped threads and they seem OK. Or the above-mentioned backwards mounting of the mount.

I'm going to reinstall the factory profile again and then put it back on the bike and recalibrate. I'll let you know if I have success this time.

UPDATE: I reinstalled and hand-tightened as far as I could. Marginally better, but still fairly easy to move the PP forward/backward. It's tight enough so it's not flopping around or anything, but I'm pretty sure that over the course of a ride road vibration might be able to move it out of position. Or maybe I just have an incorrect idea about how tight tight-enough is?

STP

STP

Please provide a photo. If something is wrong we will replace under warranty

Velocomp wrote:Please provide a photo. If something is wrong we will replace under warranty

Will do. It looks normal to me, but who knows.

I just finished re-reading some of the troubleshooting steps and I see that the question of how to orient the PP in the mount is to push it FORWARD until it stops. Of course with this particular problem I'm having, trying to tighten the thumbscrew tends to push it BACK.

I'm looking forward to getting this all worked out and then learning how to tweak things with Isaac. I think that with some exprerience one could "tune" the PP to match any other power. I train at a studio with a Computrainer, which supposedly measures power very accurately and it seems like you can even tune the indoor power curve so that the PP would match. Anyway, I think it's a neat product!

STP

John,

I have taken some photos, although I don't think they really show anything. Here's an update:

1. The plastic thumbscrew grip--the part covering the machine screw/bolt--is now destroyed. My attempts to tighten/loosen it with a wrench or vise-grips did it in as it is clearly not designed for that sort of thing.

2. Using a Philips screwdriver on the machine screw still doesn't tighten it enough to stop the PP from swiveling in its mount by about 1/4 inch. As mentioned, it isn't flopping and might be tight enough to function.

3. The threads in the bottom portion of the mount seem fine--not stripped. There APPEAR to be some stripped/worn threads in the plastic PP tab, but since that is soft plastic, I'm guessing those are just ghost threads made by the screw turning.

So let me know if you want to see the pix. I would really appreciate getting something replaced--for sure the thumbscrew is no longer as it should be. Please advise on how to proceed.

Thanks.

STP

please email tgore@velocomp.com. Sounds like you need a new mount!

Velocomp wrote:please email tgore@velocomp.com. Sounds like you need a new mount!

Thanks, John. Done.

I rode ~40 miles yesterday and got what look like pretty reasonable numbers. Looking forward to tweaking/fine tuning PP so the indoor profile matches my coach's Comptrainer setup too.

Best,
Stephen