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Re: Garmin Vectors Going Prime-Time [jackmott] [ In reply to ]
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jackmott wrote:
I suppose there is the advantage of chain friction not being a confounding variable.

that is about the only theoretically possible
substantive advantage I can think of =)

well and you can use any wheel you want, but I don't care about that much.



pyrahna wrote:
I think it might be a little early, given that it was released to the public today, to be saying one product is inferior to the other. Time will tell on multiple fronts as to what the superior product is. And this is coming from someone who bought a powertap two months ago, has no plan on upgrading, and has nothing but positive experiences with the hardware of the powertap. (the software is a different case all together, but that is an easily changed thing, I just need to bite the bullet)

Curious why you think it's inferior, Jack? It may not meet the gold standard for field testing of aero and crr, but for the majority of powermeter users, that's probably not a primary concern. To discount 100% wheel compatibility is ridiculous, too. You're also leaving out BB/crank compatibility, which is a pain in the ass and very nice not to have to think of.
I can't think of another powermeter that's more universally compatible than the Vectors except maybe the iBike, and that doesn't really count...

IG: idking90
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Re: Garmin Vectors Going Prime-Time [MrSkinny] [ In reply to ]
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Funny, I was just trying to find those profiles themselves (the detailed specs). Still fumbling away on the site.

As for Vector transmitting that - it's absolutely a firmware-update only. I suspect it'll be the first firmware update we see (new-feature wise), and from everything we talked about, really just the tip of the iceberg on where they want to go with the software side.

They see it as two seperate tracks:

Hardware (i.e. cleat/pedal types)
Software (firmware updates)

They don't see for example coming out with a new Look Keo Vector in a years time. Instead, you'd likely see a new pedal type supported.

On the software side, all pedals would be using the same software - so even 2-4 years from now updates would hit all Vector units. They view Vector as a 'platform' for these updates. They did specifically mention a 4-year software roadmap for firmware feature updates.


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My tiny little slice of the internets: dcrainmaker.com
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Re: Garmin Vectors Going Prime-Time [pyrahna] [ In reply to ]
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pyrahna wrote:
I understand the basic concepts....I am just wondering what the actual calculations are. i.e. if I had data that included the left and right torques, and instantaneous cadences, how would I calculate Pedal Smoothness and Torque Efficiency? This is a personal issue of not talking about 'metrics' that I don't understand at a mathematical level.


Ok, found it. But you'll need an ANT+ account of some sort:

http://www.thisisant.com/resources/bicycle-power/


At any rate, for those two metrics, here's what it says (calculations/background). I just went ahead and snippeted those two pages. Hopefully nobody gets upset for trying to explain things...


Pedal Smoothness: https://sites.google.com/...moothnessSnippet.JPG


Torque Efficiency: https://sites.google.com/...TorqueEffeciency.JPG




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My tiny little slice of the internets: dcrainmaker.com
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Re: Garmin Vectors Going Prime-Time [dcrainmaker] [ In reply to ]
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Nice initial review. Looking forward to the full review on these, and how they continue to compare against the other PMs on your test rig.
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Re: Garmin Vectors Going Prime-Time [dcrainmaker] [ In reply to ]
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Excellent initial write up.

I'm actually very impressed with some of the details, especially the pedal pods being replaceable for $69 a pair. Damaging the pods, however improbable it may be was one of my biggest concerns with this system, and I consider that a very reasonable price to pay in the unlikely case that it does happen.

I still find the cost of the unit to be prohibitive and I subjectively would have preferred speedplay over Look, but I'm glad this is finally out the door. I just hope competition from Stages, P2Max and PT can help bring down the cost of both Quarq and the Vector to somewhat more competitive levels (imho, 1000-1200). Not exactly holding my breath though.
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Re: Garmin Vectors Going Prime-Time [tgarson] [ In reply to ]
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I have a feeling (zero inside info) that we'll see Quarq lower prices on (at least) the Riken. That's a tough pitch at that level given the PT drops and the Vector pricing. The Elsa I suspect might also have to lower a touch bit as well, perhaps just undercutting Vector.

P2M is very well positioned price-wise, but they have distribution/retail challenges (bottlenecks) that are really slowing their adoption unnecessarily. Which is too bad, it's a solid system.


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My tiny little slice of the internets: dcrainmaker.com
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Re: Garmin Vectors Going Prime-Time [iank] [ In reply to ]
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>leaving out BB/crank compatibility, which is a pain in the ass and very nice not to have to think of.

Yeah, switching the crank between bikes is easy. But my TT bike is near end-of-life, and I'm in the market for a new one. And the 24mm spindle on my Quarq is starting to really limit my options, and it's tedious doing all the research to see if some combination of "spindle reducer" shims, etc., will work. And those shims somewhat defeat the purpose of BB30/BBright anyway.

And (fingers crossed) the standard for bike pedals isn't going to change anytime soon, and is the same for mountain, cross, track bikes too.
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Re: Garmin Vectors Going Prime-Time [trail] [ In reply to ]
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Totally agree. Got rid of my Quarq because of BB compatibility issues and "standardized" everything with a Stages and 175mm Shimano cranks.

The problem is that I'm limited in any future bike choice (road/tri/cx/etc.) to something that takes an Ultegra crank. That means no fancy aero road bike, no Tarmac, no Domane, and no future superbike without adapters - currently have Speed Concept 7.0.

Biggest bummer to me on Ray's first look is that I was thinking swapping pedals between bikes would be the easiest, but I'm thinking the Stages takes that prize.

I'm happy to pay a premium for a product that works better or is easier to use, but I don't see a ton of value to me until a new bike comes out that I NEED and I can't slap a Shimano crank on it.

/kj

http://kjmcawesome.tumblr.com/
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Re: Garmin Vectors Going Prime-Time [trail] [ In reply to ]
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trail wrote:
>leaving out BB/crank compatibility, which is a pain in the ass and very nice not to have to think of.

Yeah, switching the crank between bikes is easy. But my TT bike is near end-of-life, and I'm in the market for a new one. And the 24mm spindle on my Quarq is starting to really limit my options, and it's tedious doing all the research to see if some combination of "spindle reducer" shims, etc., will work. And those shims somewhat defeat the purpose of BB30/BBright anyway.

And (fingers crossed) the standard for bike pedals isn't going to change anytime soon, and is the same for mountain, cross, track bikes too.

Exactly. My road bike is a Cannondale with BB30, and my TT bike is a Giant with a press-fit BB86. I've never delved enough into the research about it because I usually end up getting confused/annoyed/frustrated and give up. Then I start looking into Stages because it's so much cheaper, then I realize there's no Stages crank arm to match what's on my road bike, so I'm looking at buying a whole new crank for that anyway.

IG: idking90
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Re: Garmin Vectors Going Prime-Time [dcrainmaker] [ In reply to ]
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Thanks....that is exactly what I was looking for.

And thank you for your continued value to the community. I for one appreciate you taking the time to delve through all this. A lot of it isn't that hard conceptually, but it takes a lot of time to do it correctly, and you definitely do it correctly.
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Re: Garmin Vectors Going Prime-Time [Sword] [ In reply to ]
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Thanks, as always, to Ray. People who haven't collected comparative PM data don't have any idea how much of a pain in the butt these comparisons are.

Here's a little comparison plot of the imputed gear ratios for Ray's solo mountain ride (well, the first 10km or so). X-axis is distance in km from start of ride, y-axis is imputed gear ratio based on recorded speed and cadence. Which is the Garmin Vector, the PT, the Quarq, and the Stages?


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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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As a lay person (ignorant of such things) looking at those charts it seems top right and bottom left are very similar and 'crisper', making me think they are the 'best'. Followed by top left based on 'crispness' with bottom right brining up the rear.

What do they really tell us?
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Re: Garmin Vectors Going Prime-Time [TheRhino] [ In reply to ]
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In this particular case it tells us that the quality of data being recorded by the PMs differs. The plots show the gear ratios that are imputed from speed and cadence. Since on derailleur bikes the gear ratios are discrete the imputed gear ratios ought to line up in discrete rows. Either the speed or cadence signal for the PM in the lower right is obviously of lower quality than the other three. Since I posted this, Ray has clarified that the speed signal for the lower right PM was off. We still don't yet know if the cadence is off but it's kind of cool that we can spot the data quality issue from such a simple plot.

The cadence signal for the Stages when it was initially released was off, and it appeared to affect the power measurement. (BTW, the Power Tap doesn't rely on cadence measurement to calculate power so we don't usually care if PT cadence is off since it doesn't affect power).
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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I've been out of the tri-world for a year and a half due to a torn peroneus / ankle reconstruction, and I remember thinking to myself, 'At least the Vector will be out when I come back' and it wasn't. Its about friggin time!
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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If the speed was off by a fixed amount it would just shift the dots up/down but still be crisper, yes? Looks like the speed data was variably off through the ride. Tight dots would also just indicate precision, but not nessicarily accuracy, identical dots from multiple units would indicate accuracy? I guess as long as you use the same system each time precision would suffice.
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Re: Garmin Vectors Going Prime-Time [TheRhino] [ In reply to ]
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TheRhino wrote:
If the speed was off by a fixed amount it would just shift the dots up/down but still be crisper, yes? Looks like the speed data was variably off through the ride. Tight dots would also just indicate precision, but not nessicarily accuracy, identical dots from multiple units would indicate accuracy? I guess as long as you use the same system each time precision would suffice.
Shifting of the imputed gear ratio up or down typically means the tire rollout was improperly entered. "Smudging" of the dots means that *either* the cadence *or* the speed was improperly recorded (or, occasionally, both). Ray has said that the smudging in the bottom right was because of errors in GPS speed. Errors in speed like this mean that you can't do aero testing as well. Errors in cadence, which we've seen elsewhere, mean you can't do QA-type analysis as well.
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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Only cadance is used in calculating power (excepting the Powertap) so smudgy dots could mean imprecise power then as well I take it? Thanks for detailed explanations, appreciate it.
Last edited by: TheRhino: Aug 7, 13 17:06
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
Since I posted this, Ray has clarified that the speed signal for the lower right PM was off. We still don't yet know if the cadence is off but it's kind of cool that we can spot the data quality issue from such a simple plot.

Yes. That's very cool...but, assuming the lower right PM was not the PT, does that mean that he didn't pair the separate head units to the same wheel speed sensor for the Quarq, Stages, and Vector? I'm not sure why he'd do that...

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [TheRhino] [ In reply to ]
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TheRhino wrote:
Only cadance is used in calculating power (excepting the Powertap) so smudgy dots could mean imprecise power then as well I take it?


Yup, that's why I look at the quality of the cadence signal. Except for the Power Tap (and the old Polar chain-based PM and the iBike) you have to have both torque and rotational speed of the crank (that is, cadence) in order to calculate power. One of the idiosyncrasies of using non-round chainrings is that the rotational speed of the crank isn't constant so you can get a biased estimate of power if you don't take that into account.


Tom A. wrote:
Yes. That's very cool...but, assuming the lower right PM was not the PT, does that mean that he didn't pair the separate head units to the same wheel speed sensor for the Quarq, Stages, and Vector? I'm not sure why he'd do that...

I think it just fell through the cracks. Synchronizing all four power meters and zeroing them and doing all that other preparatory crap is unnatural and, in many ways, we should be thankful that Ray takes so much care and overlooks so few things. You and I know that doing careful testing is way harder than people think.

Last edited by: RChung: Aug 7, 13 17:34
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Re: Garmin Vectors Going Prime-Time [RChung] [ In reply to ]
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RChung wrote:
TheRhino wrote:
Only cadance is used in calculating power (excepting the Powertap) so smudgy dots could mean imprecise power then as well I take it?


Yup, that's why I look at the quality of the cadence signal. Except for the Power Tap (and the old Polar chain-based PM and the iBike) you have to have both torque and rotational speed of the crank (that is, cadence) in order to calculate power. One of the idiosyncrasies of using non-round chainrings is that the rotational speed of the crank isn't constant so you can get a biased estimate of power if you don't take that into account.


Tom A. wrote:
Yes. That's very cool...but, assuming the lower right PM was not the PT, does that mean that he didn't pair the separate head units to the same wheel speed sensor for the Quarq, Stages, and Vector? I'm not sure why he'd do that...


I think it just fell through the cracks. Synchronizing all four power meters and zeroing them and doing all that other preparatory crap is unnatural and, in many ways, we should be thankful that Ray takes so much care and overlooks so few things. You and I know that doing careful testing is way harder than people think.

Yup, the reason the Vector one (810) wasn't paired (speed-sensor) was simply that they gave it to us that morning to use, all pre-paired with our pedals. So while I did some quick change of the data fields, and validated stuff like the FTP and 1s recording, I didn't think to add in the speed sensor (7AM, folks rushing to get everything done and out the door). The others were all using the same speed sensor (or at least, baring anything, should have been) - only a single speed sensor on the bike right now (speed-only). Later on in the day we'd all run through the whole new-pairing process again, but this was just to get folks out the door in the morning.

It's on my list for tomorrow's long ride. I've gotta get all the units updated to the latest firmware versions, as in talking to them the updates for the Edge 800 would change power recording for the non-PT units, so I want to ensure all units are at least recording the same way going forward. So post FW updates I'll be running through my usual checklist...


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My tiny little slice of the internets: dcrainmaker.com
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Re: Garmin Vectors Going Prime-Time [rruff] [ In reply to ]
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rruff wrote:
Torque Efficiency speaks to the ratio of positive and negative power – in other words, how much your pulling up versus pushing down. Pedal Smoothness is how even your pedaling is over the course of the stroke.

The problem being that these terms and metrics give the impression that they are a "universal good" when they aren't by a long shot. I envision lots of salesmen pretending otherwise, and novices wasting time trying to maximize these values.
Just to clarify, it is not a measure of pulling up v pushing down, rather it's a ratio of the net torque applied (i.e. sum of the positive and negative torque, ie. torque both with and opposing the direction of crank rotation) to torque only applied in the direction of crank rotation.

And yes, having a ratio < 1 does not mean bad things.
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Re: Garmin Vectors Going Prime-Time [Watt Matters] [ In reply to ]
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Torque Efficiency is an interesting metric and can help you understand why your power balance may be off. In my case the neuromuscular ability of my left leg to not generate negative torque on the upstroke seems to explain my slight left / right imbalance. At lower power your torque efficiency is lower than at higher power. If you think about it for more than a minute you will understand why...
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Re: Garmin Vectors Going Prime-Time [Watt Matters] [ In reply to ]
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Torque Efficiency actually looks like an interesting metric. Pedal smoothness on the other hand doesn't look nearly as useful. Can someone explain to me why I should care where my torque is distributed in the pedal stroke as long as I am pushing at some point in time?
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Re: Garmin Vectors Going Prime-Time [dcrainmaker] [ In reply to ]
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dcrainmaker wrote:

Yup, the reason the Vector one (810) wasn't paired (speed-sensor) was simply that they gave it to us that morning to use, all pre-paired with our pedals.

Aahhh, I see...so the Vector's 810 was using GPS-based speed then?

http://bikeblather.blogspot.com/
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Re: Garmin Vectors Going Prime-Time [Tom A.] [ In reply to ]
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Correct.

I'm just headed out the door now for along ride or two, but all units are now on the newly released firmware (800's/810's), and also, all units now are set to speed (including the one they included).


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