My situation: I live in the US during the academic year, and (at least pre-covid) usually return home for the Christmas holidays and for the summer. I have two bikes: one in the US, and one back home. I have a kinetic road machine with the InRide sensor which I use quite regularly between October and March. I don’t race, but I enjoy training with TrainerRoad because I like to improve. My bikes are not particularly fancy (Specialized Roubaix, 2011 with SRAM 10 speed and Cannondale Six Evo 2015 with a Campy 10 speed), but it doesn’t bother me.
I’ve been torn for months between getting a smart trainer or a power meter, and after much thinking I settled on the power meter, in part because, unlike the smart trainer, I would be able to use it both indoor and outdoor, and also both in the US as well as at home during the summer months (where I do much more climbing than in the US).
As to my question: I was relatively convinced to get the Favero Assioma UNO, but now I’m having second thoughts, as I realize that it can give an inaccurate reading because of imbalances between legs. Is this something that is going to affect me much, coming from an InRide Sensor? On one hand, coming from a relatively primitive setting that has proved effective in the last 2 years and a half, I want to dismiss the need to obsess over super accurate data. On the other hand though, spending quite a bit of money for something that I already know that is going to be inaccurate annoys me.
I’m guessing that, given the situation, having the favero uno probably won’t be a big problem, but I’d love to hear your thoughts, as this would be my first power meter, and I’d rather not screw up 
ifyoucantakeit: I have the DUO. Its advantages:
. accuracy;
. if you have a serious leg imbalance, it can make you conscious of that and thus make some efforts for strengthen the weaker leg.
For the UNO:
. cheaper;
. precision, so long as leg imbalance does not vary over time or with power etc;
. can be calibrated against the Inride.
In other words, so long as any imbalance does not vary greatly over time, the UNO will give results that are consistent from ride to ride, from indoors to outdoors.
You can upgrade the UNO to a DUO, later, if you want. If spending the extra [for DUO] is an issue, I think that the UNO would be perfectly adequate. Getting a UNO will be great; getting a DUO will be a little greater.
Incidentally, I think that buying a power meter over a smart trainer is a really smart move; Indoor - outdoor; and portability. The power meter will transform your outdoor riding, if you are aiming to train outdoors rather than just riding around / riding with buddies / enjoying yourself.
I’d add one advantage of the DUO. If one of the pedals goes bad and starts spitting out incorrect numbers you have the other one to check it against - your L/R balance should change over time.
I’ve found my leg imbalance changes quite markedly with cadence. Quite logical if you think about. I got an Uno a couple of years ago. I’ve now got a Duo and wish I’d got that at the start
I probably have a leg imbalance, as most people do. The problem is I’m not sure I’m ready to shell out the money for a DUO, which is obviously a better option. I guess my question is, given my situation, is the UNO good enough, or should I not bother and just keep using the InRide when I train at home?
I’ve got the Duo’s and would highly recommend you splurge for them or wait until you can afford them. The price differential isn’t that great but the differences between the two are great. You won’t be disappointed.
I think that after reading your post, in the longer term, you will say that you wished you got the DUO. I have not regretted the little extra expense.
If you can afford the Duo by all means get them. However, when I bought my Favero power meter I could only afford the single sided one at the time. I probably could have saved up and got the dual sided version but I am glad I didn’t just having the power metric to train/ pace to has been great 
If you’re concerned about cost, the UNO is good enough.
The main issue with a single sided pm is they don’t account for leg discrepancies but I don’t think it’s as important as it’s made out to be.
Leg discrepancies are usually only a couple of percent. When you ride outside, you’ll likely be more than a couple percent off target unless you have ideal training grounds for your ride. I have DUOs and am often well off target due to surface conditions, grade changes, wind etc. Some intervals I might be within a couple of percent of target, others I might be 15% off target. Outside, I view the power target as a guideline and try to hit it but don’t worry about being perfect.
If you feel you need to be on target all the time, then you might be better off with a smart trainer.
There was a recent podcast episode on training cheaply and I recommend you listen to that section for some good info.
What do you have now, UNO or DUO? And, if you switch from the UNO to the DUO, have you noticed significant differences?
I guess I could get the UNO and upgrade later, but it’s more expensive, so if that’s the plan, it would probably make more sense to get the DUO right away.
I’m also unsure if a DUO would be overkill in my situation. I enjoy training with trainer road and riding, but I don’t race and I’m not super competitive: I enjoy improving myself and see if I can get faster on the hills near home, but that’s about it.
I have the fore runner the Be Pro S. I planned originally to upgrade it at some point to dual sided but never have. The single sided version still seems to suit my needs
I don’t plan to use trainerroad workouts outside too much; it may happen, and it’s nice to have that option, but that’s not the main purpose. My thinking behind a powermeter is: 1) To train inside on the Kinetic Road Machine: more accurate and no need to calibrate it 2) To bring it home when I travel, and to use it to pace climbs and/or the occasional work out outside 3) IF I were to buy a trainer also when I’m not in the US, I can get a dumb one, and still be able to train indoors effectively
I think your plan of Kurt + power meter is the right move on a budget.
If you want a number that is accurately transferable to events and categories riding with OTHER people then duo is the one to go for. UNO opens up a large margin error here with say leg imbalance of 10% and 2% accuracy +/-.
If you only need for training then power data is just a numbers game and data only need to be relative to a single source as long it’s a consistent source. So an UNO is more than adequate as long as you are committed to using it forever. The minute you decide to bring a dual sided power meter in to the equation all of your training numbers need to be reassessed
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I have a genuine question regarding users of the Duo vs. Uno-- how does having power readings from both legs help? Rather, what do you do when you know you have an imbalance? Do you find yourself doing single-leg drills more often, or focusing on iso-lateral movements in the gym to try and correct it?
I have the duo, but I wish I’d settled for a uno. Thanks to the duo I know my left/right balance is roughly 52/48, and that knowledge is good for absolutely nothing. My previous power meter was a one-sided bePRO S.
Duo is better for comparing wiener sizes aka FTPs with friends and enemies, or monitoring recovery from a leg injury; uno is just as good for anything else, and cheaper.
Some people throw around ideas of trying to correct an imbalance that is not caused by recent injury, but every piece of advice I’ve heard from competent people, including from the TR crew, has been to forget it. We’re all assymetric and that’s just OK.
I imagine a better question would be: is having the UNO going to impact the negatively the training/intervals of TrainerRoad? If the answer is no, because the number it provides, while slightly inaccurate, is consistent, then I’m set, that’s all I need.
My fear is that the answer to that question is “who knows?,” because the imbalance changes depending on fatigue/cadence, and possibly between legs (e.g. 52/48 at times, 49/51 at other times).
I had the UNO and upgraded to the DUO. Depening on fatigue, intensity of the effort and other factors I am usually at 53-52% Right, 47-48% Left.
When I upgraded it was nice to see extra power
Did I really need the updgrade? No! UNO will allow you train with power perfectly well.
However if you can afford it, why not? It will maybe show you patterns and info that will help you understand yourself better.
For instance when I am super fresh and flying I barely have any inmbalance.
As other people have said, I got the DUO because I have a lot of body imbalances, which become more apparent in my power output as I fatigue. More than anything, the DUOs helped me break some bad habits that I had ingrained of significantly favoring one leg over another. But I think it depends on how good your own body awareness is.