I think you can safely assume something is not calibrated correctly. 50% jump in power for a similar ride? Either there were hurricane winds or something is fishy.

Yes, I'm trying to figure out which one :-).

ETA: or is there that much variation across sharkfins and other 'readers' of power? Nothing changed other than the sharkfin, lyc was the same.

Have you gone through and looked at what the calibration centers around?

LYC dropouts also tend to look exactly like that, too. I'd replace the battery, and wipe down the gold-plated connections on both the cradle and the LYC.

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

I'll clean the connections, thanks for the tip.

I looked through the manual, it says you might need to recalibrate when you pair a new lyc with the hub. In this case, the lyc and hub were the same, only the cradle/sharkfin was different (even the cadence wire was left on when I took off the old sharkfin) so I wasn't sure if that would come in to play. That said, I did zero the torque tonight before my trainer ride (I have it on auto-zero but I know that doesn't always do it). My trainer vs road power varies quite a bit so I didn't learn much from the trainer ride tonight other than it's a shitload lower on the trainer than on the road, just like it always was ;-).

I can't remember if I zeroed the torque prior to the second ride in question or not ,but was thinking that might be the issue (while at the same time thinking why would it matter if the lyc and hub were the same?).



CJ

It shouldn't matter in terms of calibration. I was more wondering from a "ut-oh" check.

Data drop outs (look at the file for a lot of low numbers interspersed with the rest), is my guess. I've had it happen to me before and a new cr2032 for the LYC fixes it.

Could also be placement of the pickup. Make sure that's fixed up perfect. Each one seems a bit "special"

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

I did put this/second sharkfin a bit lower than the old one (closer to the hub) and wondered if it was dropping out when using the old one (it's reading higher now so I don't think dropout is the problem, at least, I don't think it's droping out with the newer harness.

I'm thinking there's some formula where we put in my weight, distance, speed, avg watts, torque, etc and solve for something, and some variable would be out of the park with one set of data and the other would be at least reasonable. 'Work' didn't go up 123kj.

Ah! Sorry, I've been reading this backwards. That the new harness is reading lower. Mea culpa.

Watts are watts as far as KJ are concerned (that's avg-power * time)

Things may be working fine now and was dropping out before. Rezeroing is something I do every ride, even though I don't exactly remember it going wonky ever. Might have in this case, though.

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

I guess I'm thinking one of the following is just blatently/glaringly unreasonable (unfortunately, I'm pretty sure it's the 328/23.4) or more unreasable than the other:

155lb dude, decent setup, flattish course, a slight wind (head & tail) doing 328 watts for 17 minutes = 23.4mph

or

155lb dude, decent setup, flattish course, aslight wind (head & tail) doing 208 watts for 17 minutes = 23.6mph

In the end it really doesn't matter as long as I'm using one or the other (I understand it's all relative). I just find it odd that the numbers from the hub to the lyc could change/vary at all based on the change I made (the sharkfin/cradle). Well, I also have the issue of doing Augusta in 2 weeks and my #'s, at least from the one ride I've done, aren't usable and I'm wondering if I need to (quickly) find a new sharkfin.

I'm highly doubting the harness. You may have had both dropout problems and a wonky hub before, and now just a wonky hub. See what it calibrates to (digging deep into the menu structure)

328 w from a ~70 kg dude is pretty beastly for 20 minutes. 208 watts, seems way too slippery for not having every aeromagiggy on you for the ride. Or a wicked tailwind. :)

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

Exactly, neither one really seems right, lol!

Certainly eyebrow raising. Sorry I can't be of more help. If it calibrates up around 512, then you can trust that you're pretty much an aero brick and a monster. :)

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

Lol, I appreciate the help, thanks! I've been out of town since the second ride and will probably ride tomorrow, so I'll at least have more data (worthless or not ;-). btw, I have a pic in my profile that should be close to my current position (I add a spacer for HIM distance), I don't think I'm a brick.

you said "not all out" but that's not very specific. was it hard? how hard?

at 154 lbs, 208 would be very average (3 w/kg) and 328 would be very good (4.7 w/kg). what kind of cyclist/athlete are you? do you find yourself blowing past people when the road goes uphill?

also, with a p2, flo60, and disc cover, 24 mph at 208 W is very possible while 24 mph at 328 W seems very slow on a flat course unless there was a massive headwind.

the old (lower) reading seems more realistic to me but it depends on your ability.

Look at the raw data for times where your cadence was zero (coasting); if any time also shows a non-zero torque, then the power meter was not zeroed, so your power will be wrong.

Data dropouts would not be the issue, as they would cause the distance/time to be wrong and, unless the dropouts were non-randomly distributed across power outputs, they wouldn't affect the average power very much.

My guess is that you had a positive torque at zero cadence with your 328W ride.

---

----------------------------------
"Go yell at an M&M"

I'll look in the data for 0 cadence/postive torque, I don't rememberr seeing anything over 0 when I was not pedaling though.

I've zero'd it out for today's ride so I'm hoping things go back to normal. I have never had an issue before changing out the cradle, which shouldn't affect torque, etc, which is why this is so odd. That said, I agree with Climber7 that the 208 is more realistic (b/c that's what I'm used to seeing), as my position isn't that bad (328 and only 23.x mph), lol.

CJ

Torque values at zero cadence were high on the second ride.

So there we have it!!


CJ

As a matter of an odd distinction, I've seen a couple of wonky cases where the recorded torque values on a dropout go everywhere, but it still registers speed consistently. So the speed/distance never fell apart, but the recorded power at those instances got very funny. Then, the very next ride, I saw full-on dropout, as you describe.

---

The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important.

-Albert J. Nock

I don't understand how a different harness could affect torque values. I've never had an issue with any other ride though, but could just be a coincidence. I figured when I posted this it would all get cleared up when I made sure to zero it out before I rode with it again. My guess is that it will be back to normal going forward.

CJ

So what do I win?

By the way, with some serious Googling, you can find a spreadsheet that will fix the file for you.

---

----------------------------------
"Go yell at an M&M"