[Closed] Power Meter - worthwhile investment?

john_l - Member

Is anyone doing an mtb spd pedal system yet, or are they still all road based?

That's the one thing that's putting me off at the moment - I need to be able to swap between bikes but off-road.

but though generally this was all but fixed with the Gen2 units

I wonder if Haze from this forum would care to comment on that 😉

A lot of it depends on what you are looking to do with it. And some knowledge on how to use it.
Power is just a tool really, don't get hung up to much on the numbers.

Currently I would avoid stages/4iii

Much better off with a power tap/quarq unit.

I'm on my 2nd Gen 2 Stages and am already having leaking issues after 6 months.

However, I wouldn't worry about where you buy it from - I've had mine sorted by going through Stages tech support even though I bought it from Germany. My replacements have been sent to me via Saddleback in the UK, but I didn't ever need to contact them myself - Stages did all of that for me.

I've used a 4iii for six months now. So far so good. Seems good on battery life

I had them for it to an xt crank which I swap between to mtbs. I had them fit it as I ride 165s, they turned it round quickly.

Great input, thanks.

Would you dare to buy a 2nd hand unit? If so how much cheaper would it need to be? And would it need sending back to the manufacturer for recalibration etc?

Currently I would avoid stages/4iii

Much better off with a power tap/quarq unit.

Would you dare to buy a 2nd hand unit? If so how much cheaper would it need to be? And would it need sending back to the manufacturer for recalibration etc?

Not if it was a Stages unless I was confident they'd honour the warranty (and is why I went for a new 4iiii from a proper retailer for peace of mind).

AFAIK most if not all PMs can be re-calibrated by the user - my Garmin prompts me as to whether I want to recalibrate mine every time it fires up.

sweamrs has a 4iii unit fitted to 105 cranks on her road bike for almost a year. Now admittedly it doesn't get the hardest life (trainer mostly with the odd road ride) but no problems yet.

Having taken up triathlon and training alone. I'm feeling it not having a power meter. I've got my first ironman on Sunday and my biggest worry is blowing it on the bike leg as it's an undusting course I've no idea how to pace the bike leg. Whereas I can pace a marathon down to 10 seconds per mile.

Currently I would avoid stages/4iii
Why?

I'd avoid Stages just because of all the moisture/battery issues they still seem to be having, even with G2.

Having said that, I did buy an XT Stages for the XC bike, it was very cheap in the sales and I rarely ride it so wouldn't be too bothered if I had to spend weeks on a warranty.

See no reason currently to avoid 4iiii. Could have been tainted in some minds with the cheap single sided crank arm Stages brush.

Much better off with a power tap/quarq unit.
Again, Why?

PowerTap is good but can be a pain in terms of servicing and bearing changes. I got years of use out of an old hub on the turbo but now need to send it off as the bearings are shot. And they often come back claiming the torque tube is no good and needs replacing too, which can be expensive. Tied to a wheel to so can be a bit limiting in terms of optimising wheels for the riding you're doing.

Quarq, only heard good things about them. No estimation going on as with single sided either. Out of the 4 mentioned I'd go for the Quarq if budget allowed.

Is going single-sided (either crank or pedal system) false economy - i.e. to people find themselves upgrading to a full system and if so, why?

John_l. Depends. If proper dual sided then it can give you a fair bit of extra info. E.g. what the balance is between left and right, and more importantly how that changes with effort and fatigue. For some people this might be big, others it might be small.

Not really a big issue if you aren't that serious about the data. It gets to be more of an issue the more performance analysis and modelling you do. And it's an issue if you have multiple PMs where some measure single sided and other total power, the data may not be directly comparable.

Thanks, that helps - I've got access to a Wattbike which gives me balance data. Seems the BePro S is discontinued, so I guess the Vector S2 is the only other pedal option?

Currently I would avoid stages/4iii

Why?
Much better off with a power tap/quarq unit.

Again, Why?
Would you dare to buy a 2nd hand unit? If so how much cheaper would it need to be? And would it need sending back to the manufacturer for recalibration etc?
Not if it was a Stages unless I was confident they'd honour the warranty (and is why I went for a new 4iiii from a proper retailer for peace of mind).

AFAIK most if not all PMs can be re-calibrated by the user - my Garmin prompts me as to whether I want to recalibrate mine every time it fires up.

There is currently a lot of literature with concerns about the stages, around validity, robustness, reliability etc.
there is a lot of deviation between stages themselves. Currently I would not be using a stage for any field based research. Only would I really be confident in SRM/Powertap.

Quarq and SRM allow you to calibrate on a first principle basis, which you can't really do with a powertap nor many others.

Stage's are not sensitive, they are badly effected by vibrations; okay only proven at 48 Hz and 52 Hz.
across 13 units, it had a coefficient of variation 2.0% +/- 1.4 (statistically different from SRM and Power tap)
and a mean deviation of -2.9% +/-3.9. Which in the paper i'm quoting from was the highest reported. And stages assumes that there are no bilateral differences (debate for another time)

It would suggest that there is some form of gain error within stages, the bigger the W the bigger the error so you can't be sure if you have improved unless it is a big increase, in elite sport you need to be able to detect a change of 2%. You often get power spikes as well, hence why I said to avoid stages, plus numerous problems with them. Using similar designs and principles I can't see 4iii being any better. But I don't have much to substantiate 4iii either for or against, more just an educated guess on it.

For me personally, I would just never be 100% confident in what the screen is showing to be true! Hopefully over the next few years they will improve. For the money they seem like a good option.

Also calibrating on the Garmin headunit is not an actual 'calibration' it zero offset, only certain meters allow you to calibrate them so you can adjust the slope on them. typically done statically, with a known weight hanging off it in around 4 different position, in each ring and then you can adjust if needed.

There is already a what PM thread, but I wouldn't discount P2M or Rotor. Stages and similar are what they are... a gateway drug in to the world of PM's 🙂 Sure other options have advantages but you pay for it, depends what is important to you

a gateway drug in to the world of PM's

Is a bit like that. Started with a PowerTap hub, then a P2M, then a single sided Vector, a dual sided Vector upgrade, a PowerTap C1 for the turbo bike, and finally a Stages for the XC bike 😳

Is going single-sided (either crank or pedal system) false economy

Not claiming to be an expert but everything I've read and heard from those that are is that everyone has a left/right imbalance, and there is no value in trying to train against it, so what are you going to do with that information?

If you want to be swamped with and obsess over data then maybe go for it, but the only people I know of with double-sided are people with no budget constraints who always buy 'premium' rather than as a conscious training-related decision.

but though generally this was all but fixed with the Gen2 units

I wonder if Haze from this forum would care to comment on that

Bit late to this!

Well my 2nd gen was given an extended dry out on the radiator and clean with isopropyl as suggested by support, I followed it up with a quick spin in a light shower.

It was fine next morning but dead again within a few days, will try again with a fresh battery when I can be arsed to waste any more time on it.

I know others have had a bit more luck but personally I can't recommend.

Not claiming to be an expert but everything I've read and heard from those that are is that everyone has a left/right imbalance, and there is no value in trying to train against it, so what are you going to do with that information?

First PM was a PowerTap, rode that indoors and out. Then got a single sided Vector S. Saw a noticeable discrepancy in the power between both. So put the Vector pedal on the turbo bike and did some testing. Much discrepancy that varied quite a bit with fatigue and effort. I set the scaling factor on the Vector to an average of the discrepancy and that brought things more in line but it still wasn't tracking that well. Eventually got the second Vector pedal and that sorted the problem. Looking at the data it's obviously down to the left/right imbalance and, more significantly, the variable nature of that imbalance.

I don't do anything to work on the actual imbalance, I'm pretty sure that's a waste of time. You'd also need something like a Vector or PowerTap P1 to capture actual left and right, a Quarq for example is still estimating though from total power (my Vectors and P2M give different values for imbalance as they're based on different methods.) While the imbalance data is quite interesting, I don't think it's actually that useful. What is worth having is the measurement of total power.

It's a bit of a heresy, but if you want 30 second average power, or a more accurate summary than Strava, get a powercal HR monitor. Mine's been flawless, unlike the two stages I broke, and the powerpod that also had to be replaced.

The Powerpod is geeky smart, but needs careful setting up. Just done a 10 TT and paced to Powerpod power (310 Watts per lap average), and the results look very accurate indeed. Reproducibility is what matters, absolute numbers are less useful.

My next PM will be a Vector, but I probably should have paid the extra for a PM in the HED disc.

powercal HR monitor. Mine's been flawless,

Mine broke 🙁

Really? I have two. All I've ever done is change the batteries. I bought the first to replace a Garmin strap that died. The second I got free using incentives from work. I pass it around anyone that wants a go. I now use a wahoo tikr with the powercal as I though the powerpod might get get little upset trying to pair with something that's sending power Jim, but not as we know it!

The distribution of power is always too narrow but t mean is accurate.

Mine just seemed to stop transmitting.

Transmitting power and HR was occasionally a bit of a pain though as riding with it and a proper PM did occasionally frustrate when the Garmin would lose the proper PM signal momentarily and pair with the PowerCal instead.

Well I've committed now and bought a 4iiii unit that I can share between road & trainer bikes. Now considering a Powercal unit as my heart band is playing up, then I can use this for XC. Plus is I run both on my Taxc I can see how the result compare etc.

Will try this for the rest of the year and see how it goes, can always change later if not happy or new tech comes out.

Staineypants, surely if you've been training without a power meter you can do it on average speed (taking into consideration weather, wind etc) feel and heart rate? I've done 2 Ironmans without a power meter and planned my bike leg on that one, first one was perfect, second one less so but I knew the issue and decided to ignore it. Yes a power meter is a better gauge but remember you can sometimes get hung up on numbers.

I now have a power meter and I'm slowly learning how to use it! Just seems to blow my mind with complexity at the moment!

Power Meter - worthwhile investment?

Depends are you superfit already and just trying to find those little extras?

If not then getting fit first would be the way to go, you dont need a power meter to tell you that you need to get out for a training session.

I've gone from using HR monitors etc to just going out and riding/running and Im much fitter now. IMO using tech can be just an excuse when what is actually needed is graft.

Transmitting power and HR was occasionally a bit of a pain though as riding with it and a proper PM did occasionally frustrate when the Garmin would lose the proper PM signal

Indeed. My powerpod was flat at my [url= https://www.strava.com/activities/1008089942 ]last road race[/url], so I quickly swapped HR monitor from Wahoo to Powercal. Then had to pair both HR and power to the garmin, whilst truing to get it to ignore the other 60 riders! Results looked fine though. It was a pretty easy race after the attack had gone.

I still like it though.

IMO using tech can be just an excuse when what is actually needed is graft.

Well I never, I dug the PowerCal out from the bottom of a box, shoved a new battery in and it's come back to life! At least as far as Zwift goes. Maybe it was a Garmin problem and not the PowerCal?

IMO using tech can be just an excuse when what is actually needed is graft.

What's really needed is a plan that you stick to.

Good thing about PM's IMO is that you can start putting a lot more numbers into the plan. Be more specific about load and recovery. And have specific targets for rides (interval power, overall TSS, etc.) A plan with targets and a PM to tell me I'm not going hard enough made me graft like I never have before!

Btw, I ran for years without a HR. Then got one of the early Polar HR which was great. Then one of the early Garmin GPS watches to add things like pace targets. Even used a little beeping metronome to work on run cadence. Bits of technology can definitely enhance your training and improve the effectiveness of your graft.

I've just started using a smart turbo with power and have to say the info is invaluable.

You've got an exact reference point to how hard you are working compared to previous sessions, great for telling yourself if you are slacking and also if feeling fresh a real boost when you can produce numbers that you couldn't the week before.

Having the same info on the fly when outdoors is a great thing, half way up a climb you can see if you are going to blow up or also you can have a word with yourself if you aren't putting enough effort in.

Yes you can do this by feel... but not to the same precision points

I've got a Quarg - it seems bombproof. Ridden it all winter & it's never missed a beat.

I previously had some PowerTap chainrjngs - good for about 3 months & then they gave up. I think water ingress was the issue.

Power is great if you know what you're doing with it - but I wouldn't buy a power meter just for kicks.

IMO using tech can be just an excuse when what is actually needed is graft.

Definitely some truth in that - however blasting yourself all the time can lead to overuse/over training. A little bit of tech & knowledge goes a long way to preventing this from happening.

I've got a Quarg - it seems bombproof. Ridden it all winter & it's never missed a beat.

I'm surprised that's improved your power, if I'm honest.

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Lol at Quarg 😆

Those with PowerCal; if I already have a Garmin cadence and speed sensor can these be used by the PowerCal or must I have the PowerCal sensors anyway?

Ah what you haven't realised about Quarg is:

A. It's an excellent power meter.
B. You never go hungry on a ride.
C. It's better than Stans for sealant.
D. Can be used as chain lube in an emergency.
E. A tasty sunscreen.

The list goes on!

Those with PowerCal; if I already have a Garmin cadence and speed sensor can these be used by the PowerCal or must I have the PowerCal sensors anyway?

Do you mean PowerPod? PowerCal is just a chest strap that doesn't need anything else.

Powertap Powercal can be bought with speed and candence sensor, just wasn't sure if they were needed if I have the Garmin sensors?

Powercal is just a chest strap. You don't need a speed and cadence meter, although I've used my own algorithm of HR change, speed and cadence to model stages power in the past.

Set your Garmin to 30 second smoothing and it will tell you when you're slacking. It evens goes to zero when coasting downhill.

Kenny Boomboom gives PM's the thumbs up 🙂

Bream - Member
Lol at Quarg

Those with PowerCal; if I already have a Garmin cadence and speed sensor can these be used by the PowerCal or must I have the PowerCal sensors anyway?

POSTED 1 DAY AGO # REPORT-POST

I use the PowerCal with Garmin speed/cadanse sensors on my 800 Edge no problem 🙂

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