WHAT POWERMETER TO BUY?

I recommend you pick up a copy of the book "Training and Racing with a Power meter" by Hunter allen and Andrew Coggan.

They discuss the pros and cons of the power meters out there.

They also discuss how to analyze the data and use it for your training.

Edited by Nipper 2010-09-29 3:31 PM

I don't have a power meter, but I'm planning on acquiring one prior to next season.

Your cheapest option is to get a used wired power meter. Next, is a new wired one, which can be had for under $700 at Competitive Cyclist:
http://www.competitivecyclist.com/road-bikes/product-accessories/2010-cycleops-power-tap-compdt-rr-465-complete-wheel-5905.44.1.html

Wireless ones get more expensive, and start around $1000 and go up.

Garmin just purchased a company that was developing a pedal-based powermeter and the hope is that they will come out with a good product at a price point that undercuts the competition. I'd jump all over one if the price was around $1000.

Other options are Quark and SRM, both of which are crank based and start at $1500 and go up over $3000.

I'm currently leaning toward a Quark Cinqo, which is crank based and ANT+ wireless.
http://www.quarq.com/

Here is a copy/paste of an email I sent to someone on this very subject.

I +1 the recommendation to by Training and Racing with a PM or explore endurance nation. if you buy a PM, but don't use it - all you end up with is an extremely expensive bike computer.

Anyways:

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This subject is a tricky one to start - the logic is very closed circuit - so we'll just dive in someplace.

When it comes to fitness and performance - swimming and running have it very easy to quantify. In swimming you have a climate controlled environment, calm water, and a pace clock. It's incredible easy to benchmark your current fitness and performances in an absolute sense. A 21.0 50 freestyle is faster than a 22.0 50 free - no if's ands or butts.

Running is much the same - particularly when you head to a track - yes it's more susceptible to conditions than swimming, but much less so. A 2:50 marathon is faster than a 3:00 marathon. Course terrain and wind do impact running speed, but because the speed variation potential is small - i.e. you run 8:00/mile on the flats and up a hill you run 8:15/mile - the overall impact on total time is basically negliable. A tailwind or headwind may only affect your velocity by +-3 %; even less if you are running really fast.

Cycling unlike swimming and running is really, really affected by the conditions. If you've ever been crusing down the road @ 30 miles per hour feeling like a rockstar, turned a corner and suddenly are struggling to do 14 miles per hour - you know exactly what I mean. The potential for speed varation because of conditions is so much greater - in some cases swings of 100% or more are no unlikely.

So how to solve this problem - one approach is to simply rely on our bodies very reliable Perceived exertion mechinisim. Do some benchmarks and learn how different intensities feel and go from there. This works great for many, many people - many a world record has been set by folks just running/swimming/cycling by how it feels.

Another approach is heart rate. You can do some benchmark tests and learn your heart rate zones. You than cycle/swim/run and target different heart rate zones depending on the objective of your workout. Again many great results from this approach.

The problem with both of these approaches is that both PE and HR lie to you. They lie to you in different ways and at different times - and if you don't know that they are dirty rotten liars - you may not be training as optimally as you could - or even worse you could blow up in a race.

How does HR lie to you?

A couple ways - and much more insideously that HR does. First depending on your fitness level HR can take 1 to 2 minutes for an effort to raise your heart rate noticably. So if you are training or racing and working to maintain a moderate pace (say HIM or IM effort) - you could be doing a lot of surges - and never seem them reflected in your HR. Worse on a hill climb - you could hit the climb and either crest the climb and never see your HR catch up until you crest and the damage is done - or you could see your HR start to spike in the middle of a climb half way up - so you back off - no you are riding to easy because it's going to take a minute or 2 for your heart rate to catch up. Why does HR lie to you, because it's a side effect of your exertion and the strain on your system.

The worst way HR lies to you is in training. Imagine you do a threshold test and establish your zones. You start training by these zones and for a few weeks you notice that your running pace for a given HR is getting faster. However after a few months of hard training you begin to notice that your heart rate begins to become lower for a given pace/PE - but your races/testing doesn't indicate any real performance improvement. So you start to run harder to boost your HR - and the trend continues. Lower HR, Higher PE - but not performance improvements. Oopps - you're overtrained. Your HR lied to you and made you think you were more fit and needed to work harder - but what you really needed was more REST!!!

How does PE exertion lie to you? Fortunately it doesn't tell as many lies and as bad of lies as HR and it's much more predicitable. it basically boils down to, if you are really excited or fresh for a workout or race - PE is happy to tell you that to hard feels easy, and just right is to easy for the first bit of an effort. Fortunately your body realizes it doesn't like to lie to itself and after a few period of time it stops and wants to make up. Look at how many people have blown up during a 500 freestyle - because they went out way to hard - they said it felt easy - at first, but they still blew up. (Hold this scenario in your mind for later)

So we've got two ways of measuring training effort - and both of them lie to you. One doesn't lie to you that badly, and it feels bad for doing it. The other is totally unrepentent, it will do it over and over and over - and never stops.

So what to do instead. Measure the actual workoutput.

In swimming you've got a pace clock and USA swimming has long been advocating using pace zones off of a timing threshold test swim (T-3000). You do the benchmark test - and you get paces for different distances depending on the energy system you need to work. Race performances or new benchmarks tell you when it's time to swim faster. You know how hard you are working, you can safely ignore PE until it starts behaving because you know the paces you need to hit. When you can't hit the paces - you don't have HR telling you - well it's because your HR isn't high enough - you know something is up. Maybe you are sick, or jsut tired - either way time to dial it back for a few days.

For running, folks like Jack Daniels and McMillion have done incredible amounts of research, observation and leg work and come up with a very similar set of tables that correlate race performances to optimum training paces. You drop a 21:30 5k - you know exactly how fast you need to run to train different energy systems - and again due to the relative lack of impact that terrain and conditions have - you *know* if you're doing the work or not. The prime exception to this is heat - heat WILL slow you down, but it's predictable and because PE is generally pretty honest once you've gotten through your warm-up - you can use that to help meter your effort.

Relying on testing and paces as described above make it incredibly easy to essentially predict performances in races. If your training and testing indicate that you fit enough to swim a 5:00 500, that means you're basically capable of swimming something like 59/1:00/1:00/1:00/1:01 or some such - but you can't survive a 56 lead out (because it "felt" easy because I was rested and excited). Yes this doesn't account for breakthrough races - and true races where all that matters is beating someone - the time is a side effect - but it's very useful for planning. Espcially in triathlon and other time trial type events.

So hopefully by now you're on board that for sports like swimming and running heart rate is redundant at best and misleading at worst - but what about cycling. As I mentioned earlier - because of the wild varitions in speed that are possible, even though you can use PE to gauge your effort, you have no direct way of measuring the result. Two rides could both feel like they were done @ half ironman effort, but on averaged 18.0 and another 21.0. Is one because you were less fit, fresher, or is it simply terrain.

Enter the power meter. Without getting into the technical details of how it does it - it's a device that measures your direct output on the bike. It tells you how hard you are riding instantly. No 1 to 2 minute delay like HR. 30 mph with a tail wind - 200 watts. 14 miles an hour into the wind - 200 watts.

With a power meter on board - you suddenly go from being clueless about your true exertion (and things like - "Damn, I coasted for 15% of that ride?"). You realize that even though you are flying @ X mph - you aren't working hard enough to truly stimulate a training response from your body. And just like swimming and running now - you have a reliable way to measure the need for recovery or time to step it up. Can't hit your power targets and there's not an obvious explanation (it's 95 out and huge humidity) - rest - PE exertion really low for your target watts. Time for a test/race/reevaluation of zones.

More importantly you have instant feedback in races on pacing - with no lag time. You hit a hill and you instantly know to back off, shift, or drill it. Am I going to hard, am I going to easy - are all questions you can answer. You can couple this feedback with your PE (or HR if you inisit) to gauge things like fatigue, impact of heat, cold, etc.

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For me a powermeter, thus far hasn't really aided my overall biking. My actual cycling threshold power has been relatively flat for the past three years - some due to injury, some due to not doing the work to boost my threshold. What has benefitted significantly is my ability to execute in races and ensure that I ride within my limits to setup myself up for a strong run. The other man benefit is to help me train more specifically for the demands of my races and to know when I'm working to hard and it's time to back off. That added with the ability to directly compare races and workouts across weeks, months and years has been great. It helps me to understand when i made mistakes in training or racing - and identify my breakpoints and make calculated risks in races based on observations from previous races and workouts.

There is a lot of great info out there about the power meter choices that are availible.

The main ones are:

SRM - it's a crank based system - so you can run whatever wheels you want. It's one of the original power meters and is generally regarded as the standard. As such it's hands down the most expensive. I'm not sure the exact cost - but you're likely to drop $2800 on one of these new, and depending on the model up to $4000 (Crank + Computer; you can subtract roughly 700 or so if you go crank only and get a third party CPU). You can pickup a used wired model for around $1,000 if that's your thing. The system is a crank and custom computer that I really like. It's simple and does it's job - nothing fancy. The new ones are Ant+ compatible so you can get a different head unit if you want other functionality. They do require a fair bit of care and feeding to ensure that they are accurate - but if you treat it well - Rock Solid. Lots of crank varities availible (Campy, Octalink, Dura-Ace, SRAM Red, Cannondale SI - etc)

Quarq - basically the same thing as an SRM. Crank based, but not as many crank versions as SRM. The do not have a head unit - so you must use one made by a different vendor. Depending on the head unit you pick- can get in for right around $2,000.

Powertap - hub based system, so you have to build it into your wheel. So this means no disc in races (unless you spring for Zipps redonkulously expensive PT disc). So you need a hub for each race wheel. I've got one in my training wheel and one in my race wheel. You can sort of negate these two downsides by using a wheel cover. That turns just about anywheel into a disc, and if you only want to buy one hub - you can get it built into a solid training wheel and than slap the wheel cover on for races. I use the wheel cover on my race wheel to that I have a disc like wheel. The PT system comes with a computer that is like the SRM one. Simple and solid. Saris also has a more robust computer and the newer PT hubs are Ant+; so you could go third party CPU as well. Cost wise - you can get into a powertap system for $1,000 for a new one (Training wheel hub, + basic computer. If you don't mind a wired stuff - you can get a training wheel setup for like $600 bucks - unless you're on a super tight budget I'd recommend Wireless - it's sweet and super flexible.
Unlike the other two I mentioend - since the PT is in the wheel it's really easy to move between bikes (hence part of my recommendation for wireless). Saris has a wide selection of hubs that can vary the cost of their system from really cheap to potentially more than an SRM.

There are a couple other options out there and some ones that are on the horizon - but these are really the only real options that i'd recommend.

I rode with an SRM from early 2008 until this summer when I got a new bike. I moved to a powertap when I got my new bike - so I know those two fairly wheel. Disregarding cost I tend to prefer the powertap because it's a little bit more fire and forget from a care and feeding perspective - and I like the computer a touch better - mostly because it displays less information on each screen, which keeps me focused. It's not a big preference, but it's a bit.

If you do take the leap, I'd be happy to help guide you through the actual selection of parts - to make sure you get a good viable combination (i.e. DON'T buy the Elite+ Powertap hub as a Hub + Computer)

I've attached a PDF that's good reading - here is some other recommended reading about the things I talked about in this mail:

Racing and Training with a Powermeter - Andrew Coggan and Hunter Allen
Daniel's Running Formula - Jack Daniels

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As for my running - consistancy in training and execution in races. That's it.

Let me know if you have any more questions -

Harold

I use a powertap, but if I was in your situation I would be looking at a Quarq. That way you can train and race with it and not have to get ride of your current rear race wheel (H3).

Great recap on training w/power.



Edited by jamiej 2010-09-30 3:27 AM

Great recap, though if these running numbers are accurate I need to run a LOT more hills.  Some of the hills I run slow me down 1:30 pace at same RPE (from high 8s to low 10s).  But I get the point, running speed changes +- 10% with environment, and cycling changes +- 400%.

Now, where is that link to the free power measuring equipment?

Depends on the hill

FYI, I don't think that deal at Competitive Cyclist includes the head unit.

You also might want to e-mail Jorge after looking at this thread, he has some pretty good bulk discounts going on, but you need to contact him NOW.
http://www.beginnertriathlete.com/discussion/forums/thread-view.asp?tid=227310

Yes they do. Excel Sports Boulder also has the complete wired setup for $659.

Don't get a wired unit.

I have had to replace the wiring harness almost every year and it stopped working in my last IM race. The wiring harnesses are about $65 each so add $65 per year to use wired unit. If you have multiple bikes it is $65 for each. Wireless you can get extra harness for less than $15.

I'm curious though, how many miles are you riding a year?