Garmin Vectors Finally Released

At least they are according to road.cc: http://road.cc/content/news/89861-garmin-release-vector-power-meter-video#comment-187743 Going from 4 to 8 strain gauges per axle is a big change, and the metal plate on the pedal body should be a welcome change. We'll see what the reviews say....

 

I held off for a long time on powermeter ownership waiting for these, and then they come out a week after I finally pull the trigger on something else.

Looks like some nice improvements since the beta models but from the sounds of it will be priced on par with or slightly higher than the lowest priced crank systems and significantly more than hub based power.

Could be a good solution for someone with a TT bike who needs/wants to read power from two bikes but for someone with just one bike I don't see a compelling reason to choose this over another PM.

 

Could be a really good time coming up for those wanting to get a decent power meter for cheap with the Powertap drop in price.

I just asked my friend to start a wheel build with the lowered cost G3 hub which means that my current PT SL+ (ANT+) wheel will be going on sale very soon. Because of the G3 price drop I expect that I will sale my wheel for no more than $450 tops and it is in good shape. I imagine within a few more weeks there will be a lot more of these older PT wheels and hubs selling for decent prices.

I probably would have asked over $650 a few weeks ago and there are SL+ wheels on ebay that are still listed for over $900 with alloy rims. I bet those folks are not happy, but for those like me that are buying the G3 hub at a lower cost probably do not mind losing some off their current wheel. It kind of balances out and helps out those wanting to get a PM on a tight budget.

Probably just me, but the announcement of the G3 drop in price just about overshadowed the anticipated Garmin news. But even without Powertap's news I would still lean toward Quarq Riken or P2Max being that they have been on the market and are cheaper than the announced Vector pedals. DC Rainmaker preliminary review of the Vector pedals looked pretty good and seemed to be as accurate as the main players.

I am glad though to see more options for buyers.

 

IMHO, the PT price news was the biggest news or development in the power meter market in a long time, outweighing even Stages coming to market.

 

As a recreational fitness cyclist with some interest in racing, I'm leaning more toward Stages.

I've pondered what to do for a couple of years - almost pulling the trigger on a PT SL+ a couple of times or a Quarq Cinqo a couple of times. I have 3 road bikes (plus an XC bike), a 300PT indoor trainer, and four road wheelsets and have never resolved how I wanted to fully integrate power into the mix.

Initially the Vector was a strong consideration, but then as Garmin became more entrenched it became clear I was not going to be able to use my pedal of choice, which also affect my shoe choice. Figuring out which wheel(s) to build out with a PT (at the expense of a PT) convinced me a Quarq on my "favorite bike" was probably the best way to go. That way I could swap durable and relatively light, high-spoke-count wheels in and out for daily riding. When working on TTs and/or more favorable road surfaces, I could use my 404 carbon wheelset.

Brim Bros. is the ideal concept - take your power meter with you on the bottom of your shoe, but given the struggles of Garmin to stabilize one spindle and one pedal combination, I hold out little hope for the ZONE.

Swinging in the direction of Stages now. Worst case, I take a few minutes to swap a Stages arm between bikes - or buy two and have my preferred and rain bikes set up. Then I can freely swap out wheels/cassette combos with zero fuss.

For someone seriously into racing, PTs and chain ring-based meters may be the better option, but for a recreational hack (especially one 55 yo), I'm thinking the left crank arm route would give me everything I could need. DC Rainmaker did a rare second product eval and his side-by-side numbers compared very good with the more traditional power options.

I have the CycleOps PowerCal strap, which worked well initially to set a baseline. As my fitness improves the baseline keeps drifting, which makes it hard to pin down effort over the same courses. A fellow rider on my Sunday group rides has a PT and my power numbers are consistently lower (by a large margin) than his when uploaded to data sharing. Last Sunday we climbed most climbs together (ranked "cat 5" by MMR) at around 230-260 with the PowerCal for me and his PT measured 300-320+. No idea how well calibrated his PT is. Earlier in the season when I was less fit the PowerCal was closer to 300 on the same terrain.

Glad to see more options on the market, but nothing seems ideal.

 

That seems to be the hardest thing is trying to figure out what suits each of us for how we use our bikes and because many of us have multiple bikes. I have two road bikes and a TT bike.

For guys like you that already have various wheels to swap around it makes sense to go with something other than a PT hub, but I understand the struggle of finding the most efficient path. I've spent a lot of hours thinking about it, trying to look at different budget models and other aspects. There always seems to be something less than perfect for any of the scenarios when it comes to multiple bikes. The one thing I know now after using a PM is that it has become an essential tool in my training and hopeful progress even as I have no aspirations further than being recreational.

Since I was at one time a competitive lifter and spent many years keeping training logs I use number (weight, sets, reps) to track progress. So in my mind training on the bike now without a PM is about like training with weights with no numbers on the plates and only perceiving how much something weighs. Training people and myself for many years I find that most people tend to undertrain because they perceive they are going hard. When I started training with a PM after a few years of using RPE I found that to be true and holding 20 minutes at L4 was a bit tougher than what I had imagined with RPE as was the case for L5 and other variations of training in cycling. However, I will say that I have met quite a few people that have been very successful in racing that do well without a PM and a couple that don't even use a computer on their bike at all. They must do a lot better with RPE than I can do.

 

This is a (common) misunderstanding of the analysis and results. The reviews don't consider accuracy -- we only looked at the comparative precision.

 

Your statement will also apply to my post above (#3) where I incorrectly stated the Vector appears to be accurate in the DC Rainmaker review.

 

Well, that's just a "first look" review and not a full-on multi-ride analysis of the data like for the Stages. That said, one of the "ground rules" that Ray set for the Stages review was that it wouldn't include an analysis of its accuracy. He didn't want to get into the "twice the left leg" issue, so that part was skipped. That ground rule wasn't set for the Vector.

 

Unless you have to compare data across platforms, accuracy shouldn't be as important as precision.

 

People say this all the time but I think that's myopic. All power meters will break down or need to be replaced and if you don't have a way to assess their accuracy you're going to have a hard time comparing data across power meters even on the same platform. That said, it's absolutely true that not everyone needs the same degree of accuracy. Ray's Stages reviews didn't address the accuracy issue. The Vector is intended for a different set of users and accuracy will almost surely get more scrutiny.

 

And was the precision not comparable? My recollection of the review was that it was. I could be wrong, as it has been a while since I referred to the information.

I expect the "accuracy" is not going to be exact between systems anyway due to measuring points and inefficiencies of power transfer within the drive system - specifically when measured at the crank (ring-based or crank arm) vs. at the rear wheel (PT). Each system has its own bias, but what I recall from the data collected was that the various systems were "close enough" for general comparison of instantaneous and average power output, and that they were each precise enough to build a measurable training program around.

If awards in competition were to be given out like awards for power lifting, then quantitative accuracy needs to be spot on. Since cycling competition revolves around distance vs. time, accuracy of power output is of no real (competitive) value. ... a nice to have, but not a requirement for what power meters are used for. IMO

 

So long as after a break down they read as they did before, where's the issue? To someone training with a power meter I don't see how knowing that instead of having an FTP of 325 W, it is in reality 331.5 W changes anything or would require any change in training. It would seem most training issues or even performance issues or goals would be optimization problems.

 

I get it. ... just make a decision and get on with it. I do need to that if I want the additional insight into efforts to improve my performance.

 

The precision wasn't the same but, as I've said elsewhere, it isn't bad and guiding training is the least demanding use for a power meter.

Well, the easiest counter-example is those who don't regularly torque-zero their power meters, or inadvertently zero the torque at the wrong value. In those cases the precision is unaffected but the accuracy is off. If you follow different power meter lists you'll see guys who, after an important race, discover their meters were improperly zeroed and can't figure out how to fit that ride's data in among the rest of their data, or who wonder whether their FTP changed. A couple of years ago a guy claimed he had set a new PB FTP due to his way of training. When we examined his data we could tell that he'd inadvertently re-set his torque zero. The precision was, of course, unchanged. Finally, as for the Stages, we actually know that most riders don't have fixed pedaling asymmetry. That's pretty well observed in the literature but if you think that's too rarified you can even observe it in Ray's latest data sets where he rode with four different PMs: his left-right balance changes with pedal force. The Bikeradar reviewers have noticed the same thing from the data they're concurrently collecting from a couple of different PMs.

A slightly more complex example is that speed is really the result of the ratio of power to drag. You can do training to maximize the numerator and in that case you, and others, can defensibly say that even an inaccurate power meter can help you do that. However, another use for a power meter is minimizing the denominator. If that's what you're interested in doing (and, admittedly, not everyone is) then you're going to need both precision and accuracy.

 

I would call the issues with not zeroing torque, setting torque at the wrong value, and etc. operator errors., and my statements above were predicated on users operating, zeroing, and setting their power meters according to the directions/optimally. Aero testing is a different matter from training. Even with aero testing, given sufficient precision a person should be able to resolve changes in aero drag. It's not necessary to have absolute accuracy. It's only a matter of having sufficient precision. After all, if you determine aero drag from a fit of, say, ax2 +bx + c, you don't have to know to any specific accuracy the components that yield 'a'. You only need sufficient precision in the testing to minimize uncertainty or variance. If you're comparing power meter derived aero data to wind tunnel data or some other aero data, then accuracy comes into play. Even then, if you establish a baseline before any changes and find that your data is just shifted from something like wind tunnel data, then you might reasonably have confidence in your data and methods.

 

Although I am a recreational cyclist (a very slow gainer in endurance sport) and still do not fully understand all the finer details I do like having the ability to look at trends in WKO+ PMC. Since I do not have coach, other than the advice I have received on this forum, it has been nice to looks at those trends and fine tune training in a way that I am finding that balance between being progressive and yet being able to recover and keep that consistency going for weeks to months. Of my local friends I am the only one using a power meter and they think I committed to some sort of technical voodoo. But my performance has improved and their frustration with that improvement has also increased.

 

The example is one where the precision was unaffected but the accuracy was, and the consequences. Whether there was operator error involved doesn't affect the consequences of inaccuracy.

As for drag testing (I include both aero and rolling resistance) the magnitude of a potential change or improvement absolutely depends on accuracy. You're right that we can do relative "A is better than B" testing during a single session without needing absolute accuracy but soon you'll find that you can't do everything in a single session so you need a way to compare across sessions. One way is to have a standard setup that you repeat over all sessions but if you do this stuff a lot (and, as I admitted above, not everyone is in that situation) you're going to need accuracy or else the comparisons get pretty unwieldy.

 

Your paper on measuring indirect CdA is in my queue of papers to read.

 

Well, not everyone needs to measure their drag, and not all power meters have to satisfy every need for every rider. That said, that paper also includes a protocol for estimating drag without a power meter by doing coast downs. It's more trouble and takes longer but since an inaccurate power reading can actually screw up the estimation one of the good things about that protocol is you absolutely positively know the power is accurate.