Am considering going with single crank arm power meter but see conflicting info on whether using single side crank (or pedal) provides enough insight. First time user for this and really interested in tracking consistent power during training and races- not good enough yet to be too concerned about balance between left / right… thoughts?
I upgraded to dual last season and found my numbers were extremely similar. Between the two. I managed to do dual at the same time as I was upgrading my chainring so I saved a bit of money.
Do I like knowing what my numbers are? Yes, the ease of mind is great. But in he winter I use the trainer’s power for workouts so they are only used for 1/2 the year. My split for power is 48/52% right to left as well so left reading was fine.
The forum has several thorough discussions on this. The challenge is that your power balance can swing a lot based on fatigue, position, cadence, power output, etc. That will throw the values way off. They are directionally correct, but may not be useful for detailed targets or analysis. If budget is a factor, then get a single-sided that you can cost-effectively upgrade to dual-sided. If you can afford it, just get a dual sided or total power (chainring) power meter.
The forum has several thorough discussions on this. The challenge is that your power balance can swing a lot based on fatigue, position, cadence, power output, etc. That will throw the values way off. They are directionally correct, but may not be useful for detailed targets or analysis. If budget is a factor, then get a single-sided that you can cost-effectively upgrade to dual-sided. If you can afford it, just get a dual sided or total power (chainring) power meter.
^^^— this. /end-thread (but, it won’t be)
ETA: DONT GET SHIMANO!
If you want to go down one of those rabbit holes, RChung (who knows a thing or two about power data) chimes in there. If not, just do what exxxviii said.
exxxviii post above, do that.
Or get a used Assioma Duo setup. Or used Quarq.
I found my single sided meter to largely be just a “kilojoule tracker” when I had it. Otherwise, it was useless.
In hard intervals sometimes people move around on the saddle and chew the bar tape to get the work done, doing so can sway the numbers you’re seeing on a single sided. Because you’re doubling any left/right error either high or low.
I own two Quarqs, Assioma Duos, and a Kickr. The Kickr oddly reads highest IMO out of all of them, but the other three on-bike meters all seem to have the same delta to the Kickr. Meaning they all agree with each other within like 3w.
Favero Assioma pedals! If budget is the primary limiter then get single sided. Otherwise definitley go dual if you aren’t strapped for cash.That’s what I did and then upgraded to dual sided after a year or two. I think I ended up paying an extra $100 to upgrade rather than just purchasing dual sided right away.
Am considering going with single crank arm power meter but see conflicting info on whether using single side crank (or pedal) provides enough insight. First time user for this and really interested in tracking consistent power during training and races- not good enough yet to be too concerned about balance between left / right… thoughts?
Dual, otherwise you’re guessing.
I think I saw somewhere that you will get something like 85% of the benefits of having a power meter with single side and the remaining with double?
Single sided is way better than none at all but double is best if you can afford it.
For what it’s worth I use a single sided on my outdoors road bike and I am perfectly happy with it. But I know that I’m pretty close to 50:50 most of the time. Outside there is so much variability anyway but indoors on a trainer I’m pretty consistent.
At the risk of hijacking this thread there is one thing that I don’t understand about some peoples obsession with having dual and knowing **exactly **what their average power is.
I understand all the numbers and arguments but what I don’t get is when people argue that they need this because of inconsistencies in left right power and they need to know what an average is for their training as if that is the only thing that matters. I actually struggle to comprehend how imbalanced some people say they are when they might be 260/240 L/R but completely flip to say 275/280 L/R at higher power or a simple change in cadence. Some people seem obsessed with knowing they are doing 250W average and now I’m doing 277.5W average but surely there is a cost to that imbalance? is 250W average really representative of the work being done in that example when one leg is pretty close to doing the work in the higher example. Wouldn’t people be better off figuring out why they have these inconsistencies and work on that rather than focus on what their average power is? Surely doing say 248/252 and then 273/276 is better and comes at less cost? My thinking is that this would be more beneficial than say trying to raise FTP and thinking I know exactly what my power is based on an average number. A bit like running where for every 1% of L/R imbalance this supposedly comes at a 4% cost to running economy.
After writing this I know exactly what i would be buying if I knew I had those imbalances but I would work on consistency rather than try to hit average numbers.
I’ve posted ad nauseum about my experience with TWO separate Assioma SS pedals. They’re awesome. On everything, they seem super reproducible, literally down to the watt.
I have no idea what all these people posting about weird readings with SS pedals are talking about - I NEVER see anything weird with the Assiomas, ever. It’s so reliable that if it reads that I was 5 watts higher at the end of an interval or ride - I sure knew it - there has been NO instance where I was surprised that it was weirdly high or low. Maybe with non-Assioma older-gen SS PMs, but the Assioma SS are rock-solid for its readings, like down to the watt. A 10 watt difference would be a MASSIVE difference for me, like unimaginably huge in my experience, so I’m definitely not seeing these ‘power estimator’ or ‘guessing’ that people are talking about. If I rode 10 watts higher for either an interval or the whole ride, I was clearly cranking it up, and I definitely knew it! For sure, ZERO accidental +10 watts differentials that I have ever seen with my Assiomas. And I ride the same routes and do the same interval sets - a lot. (I almost wish sometimes it would vary more in the ‘right’ direction - it gets kinda boring when its’ so consistent!)
Again, this is from 2 separate different SSs. And I’ve used a Powertap hub for years before that, so I know what a really good PM should be be behaving like, and the Assioma is it.
I have plenty of cash now to burn on all things tri-related, but upgrading to DS is nowhere on my list of things to get. Because the SS is so good.
I’ve posted ad nauseum about my experience with TWO separate Assioma SS pedals.
…
I have no idea what all these people posting about weird readings with SS pedals are talking about
Yes. We know. You also don’t understand the concept of systematic error.
Works fine compared to my power tap hub. Exactly the same readings
Works fine compared to my power tap hub. Exactly the same readings
I’m curious if you’ve taken the Favero data and the PowerTap from the same side and plugged them into something like the DCRainmaker analyzer to see them side-by-side. I wouldn’t expect massive differences (the single side Favero is still good at the readings it gives) but would expect to see some deviations in tracking over the course of a ride.
You can take the data from a dual sided power meter and “convert” it to what it would look like single sided to see how the errors creep in the more you slice the data. Average power over the whole ride is the least demanding use of a power meter with the aero testing that RChung does being probably the most, but even things like zone training can be affected by the skew.
Average power over the whole ride is the least demanding use of a power meter with the aero testing that RChung does being probably the most, but even things like zone training can be affected by the skew.
Yup.
Whether accuracy and precision are important depends on what you’re doing with the data. Lots of riders seem to just use their PM in basically the same way they used to use a HRM 20 years ago, to train their FTP. If so, you actually don’t need much accuracy: if you’re using a single-sided PM, you could just cut your readings in half, and say it’s reporting just the left leg and FTP training wouldn’t change at all. In fact, you could cut your reading in half, round to the nearest 10, and subtract a constant number and it wouldn’t affect your FTP training. That’s cuz training FTP is one of the least demanding things you can do with power data.
But there are some things you can do with an accurate and precise power meter that can make you faster that you can’t do with just an HRM, or a PM that’s just “ordinal”. If you don’t do these things, that’s cool, but if you want to do them then an inaccurate PM won’t let you.
I’m now at a stage in my riding and racing career where I’m old, fat, and slow. My power is not increasing. I’m working hard just to keep it from falling. So I have to do these other things or I’d be even slower than I am. On those days, I’m just old and fat.
Aside from aero testing and workouts (FTP testing included as you said), what else would you being doing with that PM?
(I haven’t aero tested myself, but having seen your and other data, I’m inclined to agree it’s better to have a DS for that type of application.)
Anything where you have to make decisions based on accurate comparisons across individuals rather than for any single individual. But that’s kind of a rarefied application: the more usual application for an individual is training FTP. I think that a lot of that is that because training FTP is such an undemanding application, it’s very accessible to even casual users. Aero testing puts a lot of demands on high quality data and I quickly learned that when people had questions about their results, the first two questions I had were “what power meter are you using, and how are you measuring speed?”
I’ve worked a tiny bit with sprinters, who need to know something about not only their max but also how fast they can ramp up to it and how long they can maintain it, and accuracy and precision matters for them.
That’s interesting. The rest of us can get one sided power meters and donate the savings to charity.
Seriously guys, don’t pretend like you’re after marginal gains - and if you are, don’t admit it (99% of you).
That’s interesting. The rest of us can get one sided power meters and donate the savings to charity.
Seriously guys, don’t pretend like you’re after marginal gains - and if you are, don’t admit it (99% of you).
Yup.
Whether accuracy and precision are important depends on what you’re doing with the data. Lots of riders seem to just use their PM in basically the same way they used to use a HRM 20 years ago, to train their FTP. If so, you actually don’t need much accuracy: if you’re using a single-sided PM, you could just cut your readings in half, and say it’s reporting just the left leg and FTP training wouldn’t change at all. In fact, you could cut your reading in half, round to the nearest 10, and subtract a constant number and it wouldn’t affect your FTP training. That’s cuz training FTP is one of the least demanding things you can do with power data.
But there are some things you can do with an accurate and precise power meter that can make you faster that you can’t do with just an HRM, or a PM that’s just “ordinal”. If you don’t do these things, that’s cool, but if you want to do them then an inaccurate PM won’t let you.
And I wouldn’t say that these differences are marginal gains. My power is decreasing and it ain’t going back up so drag reduction is all I got left. If your power is still increasing, congratulations: you can both increase your power and reduce your drag. You can do both. That’s allowed.