cnaq

Thinking it’s time to get a Power Meter. What type do I get... pedal, crank arm, etc....? Are preowned power meters worth looking into, and if so, how old of models or too old? If new power meters are the way to go what is a good price point? I don't need and can’t afford top of the line equipment, but do want dependable equipment. Suggestions and feedback are appreciated.

Seattle Forrest

Used PowerTap hub tends to be a good deal.

What part of the bike you want a PM in depends on a lot of things. If you want to share it between bikes, if you use multiple wheels, your favorite shoes and pedals, etc. There isn't a single best way.

Cypress

I'd suggest getting a PM on the part of your bike you're least likely to replace or damage. I find that to be the crank, but those cost a little more. I wouldn't go used... I know how other racers and I treat our stuff, and I wouldn't be willing to roll the dice. In general the people using power meters are putting above-average stresses and time on their equipment.

MagicHour

Why do you want one?:
https://www.trainingpeaks.com/blog/h...ng-with-power/

...what type?:
https://powermetercity.com/2016/02/1...r-meter-types/

...then once you figure out what type is best for you, head on over to DCRainmaker and read some reviews, 2019 PM guide should drop soon:
https://www.dcrainmaker.com/2018/11/...yers-2018.html

Many other similar articles out there on the Google for further reading.

FWIW I would avoid a used PM-warranty is not a bad idea, you never know. I personally use 4iiii Precision and Stages (gen. 2) left crank arms on my bikes-relatively inexpensive, no brainer install with my Shimano groups and accurate enough for my humble purposes-although I've seen them called "random number generators" by some.

Zaskar

I may sell my SRM. It's got about 18,000 miles on it and some rub marks... okay, lots of rub marks... So yeah, ^that^ is a solid point.

I'm starting to look for another PM and, while I've bought used frames, wheelsets and other parts, I'm only looking at new PMs.

topflightpro

Buy a used SRM. Get one that says PM6 or PM7 on the back - those are the wireless versions. PM7 would be the target option.

Used SRM prices have fallen quite a bit recently, but they are bombproof. Yeah, you have to send them in every 3-4 years for a new battery, but they also check all the electronics and calibrate it, so you know your data is good.

The biggest challenge with the used SRM market is that most of what is available is 130 bcd, and I think most people now want 110.

(I should add I have three SRMs - one bought new, two bought used. All work great.)

firebird854

I currently have two bikes, each with a separate power meter, first I will say, I would never buy a power meter used, these things tend to fail... constantly... and having support is very appreciated, following are the two power meters and my experience:

Powertap G3: I bought this built into a DT Swiss wheel from powermeter city for $550 in the early fall of 2018. It works well, highly accurate, auto zeros, gives cadence and speed, although I always tend to wonder about the lost watt or two because it's so far down the drivetrain. The CR2032 Battery seems to only last around 200 hours and is generally a pain to replace (having to use a special tool it comes with which you must be very careful not to lose). This power meter is not immune to damage, I crashed twice that year, on a race when I had to brake very hard I went over my handlebars, my bike and I were relatively OK but I managed to shear off part of the cap to the end of the powermeter. In order to make it waterproof, I had to add some guerilla glue around it, which essentially sealed in the battery. This was unfortunate when it was time to replace it, I could not get to the battery no matter how hard I tried (and try I did...). I ended up driving down to Saris, handing them the wheel (I live about an hour away from Madison and wanted to avoid shipping costs) and asking for a fix, they fixed it perfectly and sent it back a few days later completely free of charge. Since SRAM bought Saris I have no idea if the process would still be this smooth, but that's how it was then.

FSA Powerbox Alloy: When I built up my new bike I wanted a powermeter that would not tie me to a particular wheelset, was dual-sided, performed automatic zero offsets, and had temperature compensation, so I arrived at the FSA Powerbox Alloy. I had the LBS install this, along with putting the rest of the bike together, it is one of the heaviest cranksets you can buy, but also just about the cheapest dual sided crankset at around $600 (In my mind, I thought of it more around $400 because I could deduct the price of the chainrings, crankset, etc. that I would have needed to buy). For this powermeter everything was hunky-dory until I needed to put in a new battery. The actual battery installation is super quick and easy, the only problem was my power meter readings were suddenly incredibly off. Instead of reading 400 watts on a climb it'd read around 30, instead of reading 200 watts when just riding around, it would read around 14, but at least it was consistent... It took awhile to fix this one, because FSA said I needed a firmware update but didn't support the power2max app that you had to do it with, power2max said they could help with the app but didn't support the FSA powerbox... after working with two different helpdesks, based internationally, for about a week and a half through emails, I was finally able to connect with the app and update the firmware. However, this didn't fix it, I then needed to factory reset it through the app... but it finally works! They both blamed Garmin somehow, if you were curious...

In any case, when I was purchasing a powermeter I had a couple of things I wanted: Dual Sided (although I don't care about L/R power, I want both legs, not one doubled for accuracy sake), Auto Zero Offset (means it does the "calibrate" you would otherwise have to manually do literally every time you coast for a couple of seconds), and temperature compensation so if I'm using trainerroad, zwift, etc. or climbing a mountian outside and have to pedal continuously in an environment where the temperature might change, this is taken into account.

On my second powermeter buy, the FSA Powerbox, I also found I really did not want to be tied to a wheelset anymore, cause that's something I change out a bit.

So, moral of the story, both of my PowerMeters still function mostly because of warranty and support, if I bought either one used, there's a good chance they'd both be in a landfill at this point.

rm -rf

A power meter can be useful, even if you don't use it for formal training.

I have a 4iiii single side power meter. It's 20 grams glued onto a crank arm. I replace the coin battery once or twice a year, and occasionally re-zero it with it's app.

I use it mostly for pacing on climbs and hard efforts. It's better than watching my heart rate, since it's more immediate.

And I upload to the free Golden Cheetah for lots of stats. I can see how that ride compares to previous efforts, and see my seasonal training load (no training plan, just from riding).

See this thread: Tell me this is an unnecessary toy" for more comments.

~~~
I may try Zwift this winter. The local club will be doing a weekly "ride" on Zwift, set to keep the group together even if the fast riders are way stronger.

A fluid trainer and a power meter would work with Zwift.

eduskator

The one that suits your budget! If I would buy one, I'd get the crank arm one.

FlashBazbo

If left/right metrics are important to you, be sure to go with a pedal-based meter. (Because of severe knee injury / rehab issues, accurate left/right metrics are important to me.) Nobody does that better than Garmin's Vector 3. I have owned left/right crank-based meters but their accuracy wasn't great (when tested, they all measured right leg low).

If left/right metrics are not important, a single-sided Stages meter provides reliable power that's remarkably accurate. (In my experience, a single-sided Stages Shimano meter was more accurate than a double-sided Stages LR Shimano crank.)

MagicHour

My usage case is very similar to yours along with using power when training indoors on Zwift, and then the subsequent pacing for my outdoor rides. In fact, I'm a weirdo that bought a 4iiii for a second bike because I got so used to seeing power# when riding Zwift.

RChung

There's a known (but not, obviously, well-known) problem with placing strain gages on right-side Shimano cranks. Yes, the single-sided Stages can be more accurate than a dual-sided Shimano crank system -- but that's not because the left side is good; it's cuz the right side is crap. The issue is the asymmetric 4-arm Shimano crank; cranks from other manufacturers that have symmetric arms don't seem to be affected to the same degree.

Atlas Shrugged

I use a Power2Max unit and find it extremely reliable. Upgraded recently to the ng version and works great.

Seattle Forrest

I was using an indoor recumbent bike at the gym last night. I'm recovering from a foot and ankle injury, trying to maintain some fitness and not get fat. It's probably the most gentle option on my tendon. But the screen just said 0 watts which was obviously not true, and pissed me off to no end. Once you get used to having that data, you realize that it has immense value. For pacing, for training, for recovery, even for testing. Once you come to appreciate the value of the data, it's very frustrating not to have.

drewtk

Post #4 above lays everything out very well. I use a pedal power meter so that I can move it between bikes, and I was already using Look pedals anyways. You can get a Favero Assioma Duo for $650, which is what I have.

If you're training or racing, a power meter is a great tool.

NoWhammies

I too have a left sided pm from 4iiii. I have nothing to compare it to, as this is my first pm, but I no no complaints. The pm works well and I replace the battery twice a year. I too use the pm to pace myself when I'm going hill climbs and to make sure I don't blow myself up when riding in a pace line and leading the group.

I haven't done anything with Golden Cheetah yet. I have the software loaded on my computer but the hassle of having to import workouts to Garmin (which I do anyway) and then export the workout from Garmin only to import the workout manually in to Golden Cheetah is keeping me from using the software.

If you like stats and numbers, pm's are a good way to go.

rm -rf

Easy Import
I import batches of ride recordings to GC directly from my Garmin. It's fast and easy.

Plug the Garmin in USB. In GC: Activity tab --> Import from file --> select the rides to import. The recordings are in Garmin --> Activities folder, and it'll remember this location for next time. If a ride has previously been imported, it gets skipped.

Accuracy
The 4iiii meter seems to be accurate enough. I've checked some steady grade climbs against some of the online power calculators for that same grade, and it's pretty close.

Most rides get a few 1 second inaccurate readings, going from zero watts to 1000 or more, then back to low watts. I sometimes use the GC Edit to locate and reduce that high watt number, since it shows up as a new max watts for 1 or 2 seconds on the CP (Critical Power) graph that I use often.

I've set some new personal records climbing some of the local one mile long, 300 foot climbs. The instant pacing feedback kept me at a strong, but sustainable pace.
And it's worked great on out of town climbs that are over 1000 feet, too.

fsdogwood

Suppose you have your rides in Strava, you can setup GC to retrieve your rides "automatically" (i.e., couple of mouse clicks). This is a new GC feature, not in the stable branch, though.
HTH.

sfrider 

A nice feature of the Wahoo Elemnt is it automatically uploads to GC, Strava, RWGPS, or any number of services as soon as it detects your home wifi network. So never any file copying, or manual actions needed, it's already on the dashboards by the time you get out of the shower. And, unlike GC, it mostly just works - if it can't reach the Wahoo backend it'll try again later, and eventually it'll sync. I think that's happened to me once.

smashndash

I think most people are too generous when describing the downsides of left-only power. If one leg is significantly stronger than the other, the imbalance is not going to show up as 45/55 across all cadences and all power levels across all rides. Your fatigue, cadence and torque levels will all affect your imbalance. Why does that matter?

Suppose you’re climbing a 4% grade at 80rpm. Fairly reasonable. Then, the grade eases down to 3%. Instead of shifting, you decide to spin up, as you should, to maintain the same power. At a higher cadence, the same power will require less torque. For some people, this can result in the stronger leg taking over, which means your left-only PM will read way lower even though you maintained the same power. This will cause you to push harder to compensate for that apparent power drop, which will screw up your relationship between RPE/HR and the power reading. Not great for pacing.

This obviously doesn’t affect everyone. I would suggest borrowing someone’s bike equipped with a true dual sided power meter, or putting it on a trainer or if they have a dual sided pedal PM, borrowing those. See what your imbalance is around threshold. What about when you’re going really easy like Z1 Z2? What about a hard 1 minute effort? Try various cadences at the same power and see how your imbalance changes. If it’s all over the place, consider getting a true dual sided power meter or at least a total power meter like a chainring/spider PM or a powertap.

waters60

+ 1 for Favero Assioma. PM for indoor training is great, particularly for intervals, where HR for short recoveries is almost meaningless. PM adds more absolute metrics and of course most training apps use them.

waters60

One question I have is can I download my data to a spreadsheet to get a better idea of trends? I used to use a Polar HRM + cadence and other metrics. It was easy to get totals and compare data. The Elemnt Bolt app is not designed to do comparisons, leaving the heavy lifting for others such as Training Peaks, but I don’t know if Training Peaks can do such totals or output a .xls file

rm -rf

I tried the GC "Export to csv". There's a row for each second of the ride that has data.
Here's the column headings:
secs cad hr km kph nm watts alt lon lat headwind slope temp interval lrbalance lte rte lps rps smo2 thb o2hb hhb


There's an Export Metrics csv too. One row per ride recording.
Here's the columns! Woah!
lots of running and swimming stats included.

date time filename axPower aPower Relative Intensity aBikeScore Skiba aVI aPower Response Index aNP aIF aTSS aVI aPower Efficiency Factor aTSS per hour Aerobic Decoupling Activities To Exhaustion Duration Time Moving Time Carrying (Est) Elevation Gain Carrying (Est) Distance Climb Rating Athlete Weight Athlete Bodyfat Athlete Lean Weight Athlete Bodyfat Percent Elevation Gain Elevation Loss Work Average Speed Average Power Average SmO2 Average tHb Average aPower Nonzero Average Power Average Heart Rate Average Core Temperature Heartbeats HrPw Ratio Workbeat stress Watts:RPE Ratio Power Percent of Max HrNp Ratio Average Cadence Average Temp Max Power Max SmO2 Max tHb Min SmO2 Min tHb Max Heartrate Min Heartrate Max Core Temperature Max Speed Max Cadence Max Temp Min Temp 95% Heartrate VAM Effect of Altitude Gradient Average Power Variance Max Power Variance Average Left Torque Effectiveness Average Right Torque Effectiveness Average Left Pedal Smoothness Average Right Pedal Smoothness Average Left Pedal Center Offset Average Right Pedal Center Offset Average Left Power Phase Start Average Right Power Phase Start Average Left Power Phase End Average Right Power Phase End Average Left Peak Power Phase Start Average Right Peak Power Phase Start Average Left Peak Power Phase End Average Right Peak Power Phase End Average Left Power Phase Length Average Right Power Phase Length Average Left Peak Power Phase Length Average Right Peak Power Phase Length Calories (HR) Checksum Aerobic TISS Anaerobic TISS Critical Power xPower Relative Intensity BikeScore Skiba VI TISS Aerobicity Response Index NP IF TSS VI Efficiency Factor TSS per hour Exhaustion Best R Daniels Points Daniels EqP LNP RTP xPace IWF GOVSS H1 Time in Zone H2 Time in Zone H3 Time in Zone H4 Time in Zone H5 Time in Zone H6 Time in Zone H7 Time in Zone H8 Time in Zone H9 Time in Zone H10 Time in Zone H1 Percent in Zone H2 Percent in Zone H3 Percent in Zone H4 Percent in Zone H5 Percent in Zone H6 Percent in Zone H7 Percent in Zone H8 Percent in Zone H9 Percent in Zone H10 Percent in Zone Left/Right Balance P1 Time in Pace Zone P2 Time in Pace Zone P3 Time in Pace Zone P4 Time in Pace Zone P5 Time in Pace Zone P6 Time in Pace Zone P7 Time in Pace Zone P8 Time in Pace Zone P9 Time in Pace Zone P10 Time in Pace Zone P1 Percent in Pace Zone P2 Percent in Pace Zone P3 Percent in Pace Zone P4 Percent in Pace Zone P5 Percent in Pace Zone P6 Percent in Pace Zone P7 Percent in Pace Zone P8 Percent in Pace Zone P9 Percent in Pace Zone P10 Percent in Pace Zone 10 sec Peak Pace 15 sec Peak Pace 20 sec Peak Pace 30 sec Peak Pace 1 min Peak Pace 2 min Peak Pace 3 min Peak Pace 5 min Peak Pace 8 min Peak Pace 10 min Peak Pace 20 min Peak Pace 30 min Peak Pace 60 min Peak Pace 90 min Peak Pace 10 sec Peak Pace Swim 15 sec Peak Pace Swim 20 sec Peak Pace Swim 30 sec Peak Pace Swim 1 min Peak Pace Swim 2 min Peak Pace Swim 3 min Peak Pace Swim 5 min Peak Pace Swim 8 min Peak Pace Swim 10 min Peak Pace Swim 20 min Peak Pace Swim 30 min Peak Pace Swim 60 min Peak Pace Swim 90 min Peak Pace Swim Best 50m Best 100m Best 200m Best 400m Best 500m Best 800m Best 1000m Best 1500m Best 2000m Best 3000m Best 4000m Best 5000m Best 10km Best 15km Best 20km Best Half Marathon Best 30km Best 40km Best Marathon MMP Percentage Power Zone Fatigue Index Pacing Index 1 sec Peak Power 5 sec Peak Power 10 sec Peak Power 15 sec Peak Power 20 sec Peak Power 30 sec Peak Power 1 min Peak Power 2 min Peak Power 3 min Peak Power 5 min Peak Power 8 min Peak Power 10 min Peak Power 20 min Peak Power 30 min Peak Power 60 min Peak Power 90 min Peak Power 1 min Peak Power HR 5 min Peak Power HR 10 min Peak Power HR 20 min Peak Power HR 30 min Peak Power HR 60 min Peak Power HR Average Running Cadence Max Running Cadence Average Ground Contact Time Average Vertical Oscillation Pace Efficiency Index Average Stride Length Distance Swim Pace Swim Swim Pace Stroke Rate Strokes Per Length SWolf Swim Pace Free Swim Pace Back Swim Pace Breast Swim Pace Fly L1 Sustained Time L2 Sustained Time L3 Sustained Time L4 Sustained Time L5 Sustained Time L6 Sustained Time L7 Sustained Time L8 Sustained Time L9 Sustained Time L10 Sustained Time xPower Swim STP xPace Swim SRI SwimScore TriScore L1 Time in Zone L2 Time in Zone L3 Time in Zone L4 Time in Zone L5 Time in Zone L6 Time in Zone L7 Time in Zone L8 Time in Zone L9 Time in Zone L10 Time in Zone L1 Percent in Zone L2 Percent in Zone L3 Percent in Zone L4 Percent in Zone L5 Percent in Zone L6 Percent in Zone L7 Percent in Zone L8 Percent in Zone L9 Percent in Zone L10 Percent in Zone TRIMP Points TRIMP(100) Points TRIMP Zonal Points Session RPE VDOT TPace 1 sec Peak WPK 5 sec Peak WPK 10 sec Peak WPK 15 sec Peak WPK 20 sec Peak WPK 30 sec Peak WPK 1 min Peak WPK 5 min Peak WPK 10 min Peak WPK 20 min Peak WPK 30 min Peak WPK 60 min Peak WPK Estimated VO2MAX Watts Per Kilogram Minimum W' bal Max W' Expended W'bal Matches Maximum W'bal Match W'bal TAU W' Work W' Power W1 Above CP W'bal Low Fatigue W2 Above CP W'bal Moderate Fatigue W3 Above CP W'bal Heavy Fatigue W4 Above CP W'bal Severe Fatigue W1 W'bal Low Fatigue W2 W'bal Moderate Fatigue W3 W'bal Heavy Fatigue W4 W'bal Severe Fatigue W1 W'bal Work Low Fatigue W2 W'bal Work Moderate Fatigue W3 W'bal Work Heavy Fatigue W4 W'bal Work Severe Fatigue Below CP Work


Or:
Instead of doing your own metrics, Golden Cheetah has a bunch of trends charts, based on different training theories/methods. There's a "Trends" tab for these charts.

I've set the charts to show 2 rolling years, so I can see how I was doing in the same season last year. All the charts have lots of settings customizations, if you want to change the chart data.

I see this set of charts. And there are a lot more in the Library tab!

I don't do much with them, but the stress charts are interesting, dropping in the winter, and peaking for me when I'm doing longer distance summer rides.

TISS, 4 trend lines, short term, long term, both aerobic and anerobic.

google search "golden cheetah TISS" has details:
TSS : Training Stress Score®. A quantification of the training session that takes into account the duration and intensity of the training based on the power data. It's intended to estimate the training load and physiological stress created by that session (it's conceptually modeled after the heart rate-based training load, TRIMP).


Performance Manager Chart
Coggan training loads: acute, chronic, and Training Stress Balance.


Aerobic Power
A chart of weekly numbers for
05, 10, 20, 30, 60 minute peak power

Anaeorobic Power
05, 10, 20, 30, 60 second peak power

Watts/Kilogram bar chart, last 30 days.
each bar is 0.1 w/kg, height is percentage of total time.

NoWhammies

[QUOTE=rm -rf;21189925]
Easy Import
I import batches of ride recordings to GC directly from my Garmin. It's fast and easy.

Plug the Garmin in USB. In GC: Activity tab --> Import from file --> select the rides to import. The recordings are in Garmin --> Activities folder, and it'll remember this location for next time. If a ride has previously been imported, it gets skipped.

<snip>[/QUOTE]

Wow. Thanks for this. I had no idea. I always thought I had to export the rides from Garmin Connect, then upload them to GC. The whole process seemed like a slog so I never bothered. But knowing this method ^^ perhaps I'll give GC a try.


Not on Strava. But this might be reason enough to get on there. If only to make importing rides to GC easier. Although the method posted above might make the whole process do-able. I wonder when the new feature will be released to the stable version.