Power meters and computers

Gear & Tech
1

Hi guys!

I told myself (and my wife, more importantly) if I could just consistently ride for 6 months and prove to myself it wasn’t another “phase” that I’d invest in gear, and I made it - so she signed off.

I was just using the Specialized Rider app with the helmet GPS thing, which worked well as I had no metrics in-ride at all, fine line between usefulness and loss of sanity chasing metrics in the past. This likely helped me just ride and not drive myself nuts. Then got Strava as the maps were helpful. Now my phone loses battery too fast to keep running those, so I need an actual computer.

Figured if I was going to get a computer I might as well get one that’s going to work with some type of power meter down the road and not need to upgrade. I’d like cadence, HR compatibility, not sure what else I’d need over those. My brief research makes me think they have cool stuff I don’t know I’d like as well.

I’ve been out of this game for 15 years so feel completely lost researching all the options, so any guidance on a set up would be appreciated. I think all in for computer and meter $1000 would seem reasonable to me, maybe I’m living in a fantasy world of 2005 prices there though!

I’m all off-road, gravel and MTB, if that makes any difference.

Thanks!

2

Hi @douglashilbert, and welcome to the forums! Thanks for posting. This is a great question. I’ll give you my preferred (and current) setup, and happy to say it cost me well under $1000, so I think you can easily make it happen!

Stages left side power meter: My road bike is a Tarmac with Dura-Ace 9100, but because I was able to find a closeout-level Ultegra Stages power meter, I went with that. The fact that one side of my crankset says Ultegra and the other Dura-Ace doesn’t bother me. I think I was all in with that one for around $350-$400.

I ended up running Stages on my road bike, and put another one on my SS MTB. The older one on the SS MTB has been through hell and back and it’s still working great. I had to replace the seal and door on it once, but other than that it has been a real tank of a power meter.

Wahoo ELEMNT computer: I switched to Wahoo after being a long-time Garmin fan, but having run into a lot of battery and functionality issues with the Edge computer, I decided to give Wahoo a try. So far the ELEMNT has been a positive experience. Very affordable, great battery life, and I enjoy the large screen. It’s not a color screen and it does very basic navigation, but the main reason I purchased it was for the data display and size. I run it on my road and mountain bikes and it easily switches between bikes, so I have profiles set up for each one. It pairs nicely with your phone, so you can have it connected, but it doesn’t eat up your phone battery. You can run Strava segments and routes on it too, which is a nice feature. I also found this one as one of their refurbished models on the Wahoo site and it was around $250 at the time. I also run a Wahoo TICKR heart rate monitor and Wahoo cadence sensor. Everything pairs nicely and just works well together. Very rarely do I experience drops in the signal.

So with that said, I think you can get into a pretty solid setup for <$1000. There are plenty of other models out there for power meters and computers, so make sure to select one that will work with your needs. I’ve seen some Stages meters that barely fit due to some wide chainstays on MTBs, so you’ll have to measure to be sure.

What have you been looking at so far?

@trevor and @chris would also have great thoughts to add since they are power meter/computer consumers too.

Coach Ryan

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3

I would second everything here. As non-pro, 40s-50s-ish (aged) endurance geek, I pretty much have the same set up - Stages single side and Wahoo. I really don’t need the dual side, since a consistent measure is enough for me.

A bonus if you are looking to have an indoor option, I have a wheel-in smart trainer (older saris mangus) that I compared the PM on the trainer with the Stages it was pretty much the same. I then bought a used starter road bike and upgraded the drive and combined with the trainer it ended up being less than a direct drive trainer alone. So, if you are ever looking to getting an indoor set up (and not have to swap bikes constantly) you can go that route and be fairly confident that things are fairly consistent.

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4

One clarification on the PM and Smart trainer PM. The readings on the trainer were consistent. Comparing riding inside and out an be different even when using the same PM.

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Hi @douglashilbert, I have a couple of Stages power meters and like @Ryan said they are a solid entry point into the power meter market. There were a few issues with the early generations, but later models look good.

The down side to a crank arm option is they tend to lock you into the bike, which is where pedals are great. Crank spider based options appear to be the more reliable but again you are locked into the chainset/bottom bracket standard plus they are a little bit pricier.

With headunits I was all sold on the Garmin eco-system. That was until I was given a Elemnt prior to launch to get a feel for it and the experience was so good I never gave it back. Since then I have used the Bolt and the Roam and have had zero issues. Of course you will always have one feature on one platform that trumps the other. Garmin or Wahoo is the cyclists version of Mac or PC.

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I’ll second the Wahoo computer recommendations. If you want a UI that hasn’t changed much in 15 years, then go with a Garmin :slight_smile: In all seriousness, the UI on my garmin 530 is still very similar to the edge 500 (from 2009). Wahoo is a much simpler device with a simpler and more consistent UI.

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I started with a single sided power meter but now I’ve got a dual sided one (Assioma Duos) I’ve found that I have a large Left/Right power imbalance (57/43) which varies not only with cadence but also as I fatigue. The single sided one was, therefore, a bit of a random number generator.

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@carytb haha, I like your ‘random number generator’ comment! It’s great when you have the ability to measure both sides as you can really see some large changes. I had a knee laceration about a year ago that shut off my left VMO for a while, and I only have left sided power meters, so luckily it was easy to watch that muscle function return, but would have been even more interesting to see the massive difference left to right with both sides being measured - would have been like 5/95 L/R initially!

Coach Ryan

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Thanks @ryankohler

What have you been looking at so far? I googled for an hour and realized I have no clue what I’m doing, so came here for help!!

The dual side is interesting as I have a surgically repaired left achilles and a non-repaired torn ACL in my right knee. Maybe they balance each other out, LOL!

10

Hi Doug,
There are a lot of options for dual sided meters currently on the market. I’m still a fan of Stages power meters and have been using them for a long time. They do have dual-sided available, but I’ve heard positive reviews about the Assioma pedal power meters along with the Quarq (DZero) as well.

I’m sure we have a lot of power meter users on the forum who would also be happy to give their personal experiences as well!

Coach Ryan

11

I have the Assioma duos and have been quite happy with them. Being able to switch them between bikes is nice. Both DC rainmaker and GPLama seem to frequently use the Assiomas as a reference when doing other power meter or smart trainer reviews.
The main downside of these (and all other road power pedals) is that they required Look compatible cleats.

Things I like about the Assiomas on the tech-geekery side of things:

  • You can scale each one by a specified factor. This is really helpful when you have multiple power meters, and you want them to all agree or at least be close. I wish more power meters had this feature. I would consider this a must-have for people using more than one power meter. I know some people with multiple power meters and the variance between them (and a high end smart trainer) is astounding - the 3 or 4 he has give a range of 10%, and as I recall no two are within their claimed accuracy ranges.
  • static weight calibration. This is a dying feature, as to truly calibrate it you need a precision weight, which is rather expensive. With Assioma’s calibration procedure, it gives you a reading (in some arbitrary units) of the weight you have on the pedal. What this allows you to do is take any weight in the acceptable range, and use that to ensure the both pedals are reading the same. This won’t give you absolute calibration, but if you are seeing weird L/R balance, this allows you to confirm that the basic force measuring circuitry on both pedals is reading the same. ** Given that you are going to be specifically interested in L/R balance, being confident that these numbers are valid is going to be important.
  • This applies to any pedal based or dual crank arm design, but these give you two completely independent power meters. This is helpful in that if one goes wonky, you can get a good indication of that in the data. A while ago I was trying to track down and document inaccurate readings from my kickr vs my assiomas, and I saw some power drift over the course of the workout. I at first assumed this was the kickr, but it turned out to be 1 of the pedals. Looking at the data after the ride this was quite obvious. If I only had a single power meter on the bike, I would have no way to tell if it was the power meter or the trainer. This is the only anomaly I have seen from the pedals, and this was on an old version of firmware.
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I have too many bikes and too many power meters. I’ve been using them for 20+ years with the original eTune (now Saris) Powertap hub system (after a couple of wet rides, the hub failed consistently.)

Like @trevor I’m kind of a PowerMeter snob. I sort of stick with what works and am reluctant to change. So, most of my road bikes have SRM. Yeah, they are a bit of a pain cuz you have to pull the crank and send it to SRM every couple of years. But they have been reliable and I don’t have to change a button battery to trouble shoot them! That said, I have 1 SRM MTB powermeter (about 5 years old) and have had nothing but trouble with it. This is a one off experience so I can’t comment on other’s experiences. I really haven’t had trouble with the 6 or 7 road SRMS I have used.

I do have a Shimano DA powermeter on one bike and like it. It has been reliable and is nice since it is rechargeable. It is dual sided so you can see L-R balance.

On my main MTB I have the Raceface Cinch which I don’t think is all that commonly used. You have to use Easton/Raceface (Cinch) cranks with it (that’s the limit of my drivetrain expertise… but the whole setup is not terribly expensive. It is single-sided spindle based powermeter with 400 claimed battery life hours and microusb recharging. I’ve had it for 2 years and am very happy with it.

Link to Cinch PM review:

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13

I love it!
#CyclistProblems
:grin:

14

I have a power meter on each one of my bikes and, because of availability and fit issues specific to each bike, each one is different. So this is somewhat of a disadvantage in terms of consistency, but an advantage in that i have experience with a few different PMs.

I have:

  1. Quarq Dzero on my Specialized hardtail MTB that i got in 2018
  2. Power2Max NG on my gravel bike that i got in 2019
  3. Stages Left-Only on my Cannondale Scalpel that i just got a few weeks ago (left-only was the only one that would fit)
  4. Elite Direto first gen smart trainer from 2017ish

All seem to be pretty consistent within themselves and have been reliable. Easy to zero-offset, all compensate for temperature well enough that i don’t get any weird results, no real issues with any of them.

Now as to “accuracy,” all of these claim to be accurate but there’s really no way to determine whether it’s true. Like, if i see a difference riding bike 1 on day 1 vs. bike 2 on day 2, how do i know that’s because of the PM and not bike position or the fact that maybe i’m more tired on one of those days? There is no way to put the same me on two different bikes at the same time (this is like the bike version of Shroedinger’s cat).

That said, the Quarq and the Stages seem to be pretty consistent with each other (i say “seem” to be because of the caveats above), and they tend to read about 10 watts or so higher than the elite direto, which i would expect makes sense based on drivetrain loss plus just different power curve.

On the other hand, the Power2max reads substantially lower than the first two, and about 10 watts lower than the direct drive PM. Now, does this mean it’s wrong? As i said, i have no idea. It could be that all are within spec, just one is on the low end and the other two are on the high end. But regardless, it’s a big enough inconsistency that it’s a little annoying. On the one hand it doesn’t really matter, because what matters is who crosses the line first and not who had the higher w/kg on the way there. But on the other hand, you end up needing to do mental adjustment when training on different bikes and sometimes you just have to accept that data you’re gathering won’t be useful for benchmarking.

I tend to benchmark to the higher two power meters because i use those bikes more often and use them more often for intervals, whereas the gravel bike i usually do longer rides where i’m less concerned with power. So it’s fine, not the end of the world, but i wish they had way of adjusting like the Assiomas do.