Viceroy

Hi all. I am riding a new Supersix EVO Ultegra 51 cm with everything as it is out of the box. I've always wanted a power meter and can now afford one. What would you suggest for a power meter? To keep everything as easy as possible for installation, and also a reasonable cost, was looking at some of the lower-cost pedal options (I use standard road cleats). I have heard the Power2max are also a good choice for Cannondales (https://powermetercity.com/product/p...d-power-meter/), but seems like this is more difficult to install. Would any of the crank arm options be reasonable (e.g. https://powermetercity.com/product/s...i-power-meter/)?

I don't need great accuracy, this is just for my own info and training but I don't race. Single-sided is therefore OK for my purposes but would consider dual.

Thanks!

Barry2 

If they made PM pedals with road SPD-SL (3 bolt) cleats, I’d get me a pair. But alas, nope, not to be.
But pedals do qualify as easy to install if you are prepared to use their required cleats.
It sounds like you might refer to SPD (2 bolts) cleat, those too leave little option for PM pedals.

I looked at 4iiii and Stages cranks. Decided on Stages due to temp compensation. All I needed for install was a cheap plastic preload key and a torque wrench, took 10mins.

Went single sided at first, had fun, purchased other side.

Barry

rubiksoval

You can buy a P2Max assembled already. All you do is install the crank.

I wouldn't get a one-sided power meter ever, but it's completely pointless at this point with all of the powermeter offerings that will actually measure total power.

msu2001la

I picked up a refurbished Stages FSA left crank arm powermeter for my C'Dale CX bike last year for like $200. Edit: It was only $120.
It was simple to install, works flawlessly, syncs with my Garmin, works with Zwift for trainer use, etc. I'd have zero concerns buying another one.

Maybe I just don't know what I'm missing with a dual-sided meter?

rubiksoval

Well, you do know. You're missing half of your power output.

Maybe that matters, maybe it doesn't.

Barry2 

Depending on the PM you are missing some of the more advanced reporting.
A single side just assumes 50%/50% split on the legs and doubles the power reading it gets from the left leg.
Dual reports a total power and the split per leg. If one leg is goofing off, you'll know.
My dual (Stages) also reports Torque Efficiency (TE), which is where I'm currently trying to improve.
If you push on the right pedal 60 pounds, but you don't lift your ~15 pound left leg while doing so, only 45 pounds of right leg pressure is moving the bike forward.
The right leg is in effect lifting the 15 pound left leg leaving only 45 pounds.
This TE percentage is just wasted power, and I'm trying to improve.

Be aware that an App like Strava does not capture or display these advanced metrics.
I capture the ride info with a Wahoo Bolt and the Bolt and it's App display those numbers for me.

There are other metrics, but I've yet to untangle those.

I didn't "need" dual, but having it has shown me where I'm losing some of the little power I have. 8-)

Barry

Atlas Shrugged

I am on my 2nd Power2Max and very happy with it. Never have given them any thought, just installed and given reliable power numbers since. When a new model became available offered a generous exchange policy so that was great as well.

guadzilla

$700 gets you a Quarq with chainrings. That's what i would get.

Bah Humbug

Well or maybe more than half, or less. That being the problem.

guadzilla

While I agree that single-legged power meters are not as precise due to leg imbalance issues, I do think they are better than nothing.

A constant leg imbalance obviously does not affect things too much - it might make the number appear larger or smaller than reality, but as long as it is consistent, you can train with it. If the leg imbalance changes with fatigue, then yes, the numbers can become inaccurate. I guess it depends on how much the leg imbalance changes - I havent really seen more than 1-2% change in my leg balance. Even if it is a bit more, does that really destroy your training?

But if you are riding recreationally, and using the power meter mainly to gauge longer efforts - tempo or SST - then being off by 5% isnt necessarily the end of the world. You still get a good training benefit. Eg, for a non-racer who is doing an interval between 245-260W, it isnt the end of the world if they are off by 5-10W on either end. Keep in mind that I am talking about recreational riders. For racers - especially competitive ones, this would obviously be a non-starter. For general recreational riders looking to get better? Ehhh, it should still work.

To be clear, I'd still prefer a dual-sided meter and am in no way saying single sided meters are just as good. And with the difference between a Quarq and a Stages being $400, a dual-sided meter is within the reach of most people who can afford a single-sided meter.

But if someone truly is budget constrained and all they can swing is a single sided meter, I think they can get good results out of it. In this part of the world, there are a lot of kids who are quite strong riders, who come from really poor families (Asia-level poor, not Western-level poor) and cannot afford expensive kit. Our team sponsors a couple of these riders with gear and training, and they have hand-me-down Stages, and use them to pretty good effect.

rubiksoval

You can buy used dual sided meters or wheelsets for the same price as a Stages of 4iii or something.

Hell, you can probably find a wired SRM for 250-300 if you looked.

"Budget" is really not an excuse at this point. Someone either doesn't care or they're ignorant of the issues (unlikely if they're searching on internet forums).

DrIsotope

The beauty is if you have more than one bike, you only "need" one dual-sided PM. Ride that bike a few times, learn that your power imbalance is never, ever more than 2% one way or the other (and I've seen 52L/48R I think three times, and 48L/52R never,) then live a worry-free life filled with single-sided PMs.

guadzilla

Fair enough...