One sided power meter

angrod

Hi,
I want to train seriously, but have a limited budget.
I searched the internet, but I'm still not convinced.
Is it worth it to only buy a one sided power meter ? ( I plan on buying the Favero Assioma )
The main thing that bothers me is that not knowing by how much my right leg puts more power, my ftp may not be accurate, thus making my training less efficient ( or making me overtrain if my left leg puts more power but I highly doubt it ).

fenix

I dont think it matters too much. So long as its consistent - thats what matters.

Or just get a turbo that works with zwift - and do your power based training indoors and leave outdoors for rides that are more fun.

StillGoing

L/R balance is not worth worrying about unless you're in the realms of a massive difference. Few people have a true 50/50 L/R balance with most being low 50/high 40 one way or the other.

angrod

@fenix yeah i was thinking about that option, but for races it will be useful to have a power meter + I have some drawbacks for indoor trainers coming from my job.

@StillGoing that's the thing. Since i don't know if I have a massive difference or not, I'm affraid I won't be able to trust my ftp too much

If anyone else has opinions about this, I'm still interested

timothyw

The thing that put me off was the fear that I might start favouring the leg with the power meter - eg when you are struggling to hit a certain number you find yourself pressing that little bit harder with the left leg and easing off with the right leg, consciously or unconsciously.

The suggestion above of getting a direct drive turbo with a fairly reliable power meter built in is a decent one, as ultimately I have found it very hard to do any kind of structured power training on the road - it's more useful for examining your effort after the event and tracking your fitness - although this could be different if you live out in the sticks (so don't have to worry about traffic on a commute) or otherwise have more time for training than I do.

Anyhow, I'd recommend you spend that bit extra and get a power2max or quarq - I got a power2max ngeco FSA gossamer and have been very happy with it.

whyamihere

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements. Unless you're racing on Zwift, the actual number is basically irrelevant as long as you can consistently measure your own performance.

joe_totale-2

They may already have gone but if not then get a set for the price of a single sided one:

https://forum.bikeradar.com/discussion/13110037/fs-favero-assioma-duo-power-meter-3t-zero25-team-seatpost#latest

wongataa

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

This is true if your imbalance is consistent. Leg imbalances can vary at different cadences, different power outputs, and different fatigue levels. You will never know if your leg imbalance varies with out a total power meter or dual sided power meter.

angrod

@timothyw

timothyw said:

The thing that put me off was the fear that I might start favouring the leg with the power meter - eg when you are struggling to hit a certain number you find yourself pressing that little bit harder with the left leg and easing off with the right leg, consciously or unconsciously.

Oh I didn't think of that either !
I totally see my self doing that.

@whyamihere

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

Yeah but you'll train using the wrong FTP. Either training too hard or not enough.
That's the thing I want to avoid.

@joe_totale-2 thanks, but I can't afford them right now anyway. Very interesting offer though.

slowbike

angrod said:

@timothyw

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

Yeah but you'll train using the wrong FTP. Either training too hard or not enough.
That's the thing I want to avoid.

It's unlikely you're that unbalanced - if people were generally unbalanced then 1 sided meters wouldn't be so popular.

If you can do a balance test it's worth while doing - I did one on a wattbike years ago - so know it's about the same, more or less - and now just use the single sided PM. Only caveat is that I'm not "serious".

Don't treat your FTP as an absolute number though - it's not comparable to anyone else (although we all do it) - just look to increase your FTP over time.

fenix

Why would you not get a true FTP with single sided ?

I would say that you can pretty easily tell if your FTP is wrong. You can tell if your sessions are too easy or too hard for you.

whyamihere

wongataa said:

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

This is true if your imbalance is consistent. Leg imbalances can vary at different cadences, different power outputs, and different fatigue levels. You will never know if your leg imbalance varies with out a total power meter or dual sided power meter.

Again, I'm not sure that really matters as long as you use the same power meter. I know that I find it a lot harder to put out 300W at 60rpm than I do at 90rpm regardless of whether I'm using a single sided, dual sided or total power meter. That's not because of imbalance, it's because I'm outside my comfortable range. As long as the same power meter is used, then it just builds up your own personal power profile, which you can still use to improve. You won't find intervals too easy or too hard because the intervals will be set according to the measurements you make on that same power meter. As stated above, unless you're doing something like Zwift races where the absolute power number matters, it's all relative if you use the same power meter.

twotoebenny

My balance is better the closer I am to my ftp, threshold efforts etc are generally better than just piddling about. I don't think it's a problem but for some reason people want to make a lot out of it... consistency is key

wongataa

whyamihere said:

wongataa said:

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

This is true if your imbalance is consistent. Leg imbalances can vary at different cadences, different power outputs, and different fatigue levels. You will never know if your leg imbalance varies with out a total power meter or dual sided power meter.

Again, I'm not sure that really matters as long as you use the same power meter. I know that I find it a lot harder to put out 300W at 60rpm than I do at 90rpm regardless of whether I'm using a single sided, dual sided or total power meter. That's not because of imbalance, it's because I'm outside my comfortable range. As long as the same power meter is used, then it just builds up your own personal power profile, which you can still use to improve. You won't find intervals too easy or too hard because the intervals will be set according to the measurements you make on that same power meter. As stated above, unless you're doing something like Zwift races where the absolute power number matters, it's all relative if you use the same power meter.

Say you are fresh and do an FTP test. Your workouts are scaled from this value. Say your leg balance is 50:50 during the test.

Say during a workout you get tired and your leg balance changes to 45:55 L:R. Now you need to work harder than the training plan wants you to to hit the power target. Say the leg balance went to 55:45 then you be having an easier workout than intended.

Say you leg balance changed at high power outputs than what it was during the FTP test. Now your sprint intervals or VO2 max workouts are harder or easier than they should be and you are training too hard or not getting enough benefit.

Now you may well accept that this could be the case for you and keep using a single sided power meter because it is good enough for you.

I am just showing how a single sided power meter may not give consistent results . It is just something to consider if you are thinking about buying a single sided power meter. Consistency is what really matters for training, not what the numbers actually are.

Of course you may well have a consistent leg balance but there is no way to know without dual sided power meters.

pippi_langsamer-2

I know I have a leg imbalance from leg length discrepancy. This was diagnosed by a specialist (also a cyclist), and proven further with a dual-sided Verve Infocrank. Thing is....what are you going to do about it? Mine was causing ITBS (which was remedied), but power is still imbalanced, but unless you're in the realms of high-level bio-mechanical interventions, best to ignore it and crack-on.

With regards a PM for racing, I don't know many friends with PM's who pay much attention to them in races. Training, yes.....but racing, you should be too busy bleeding out of your eyeballs to be looking at your stats.

(Unless we're talking about TT'ing)

w00dster

I look at mine, not overly often, but I can have days where above threshold feels easy (for a few mins anyway), but I know I’ll pay the price later in a race. It’s good to check on the power to make sure I’m not being a pillock too early in the race.
I use single sided and go on the basis that it’s accurate enough for me, I also have a wattbike for my indoor training and the accuracy seems to be pretty close.
I know my 1min, 5 min, 20 min and 1 hour power values, so training to these outdoors even with a single sided power meter is really useful.

fenix

wongataa said:

whyamihere said:

wongataa said:

whyamihere said:

As long as you only use the same power meter, it doesn't really matter. If you are very unbalanced, then you won't know your 'true' FTP, but all of your measurements will be consistent and you'll still be able to track improvements.

This is true if your imbalance is consistent. Leg imbalances can vary at different cadences, different power outputs, and different fatigue levels. You will never know if your leg imbalance varies with out a total power meter or dual sided power meter.

Again, I'm not sure that really matters as long as you use the same power meter. I know that I find it a lot harder to put out 300W at 60rpm than I do at 90rpm regardless of whether I'm using a single sided, dual sided or total power meter. That's not because of imbalance, it's because I'm outside my comfortable range. As long as the same power meter is used, then it just builds up your own personal power profile, which you can still use to improve. You won't find intervals too easy or too hard because the intervals will be set according to the measurements you make on that same power meter. As stated above, unless you're doing something like Zwift races where the absolute power number matters, it's all relative if you use the same power meter.

Say you are fresh and do an FTP test. Your workouts are scaled from this value. Say your leg balance is 50:50 during the test.

Say during a workout you get tired and your leg balance changes to 45:55 L:R. Now you need to work harder than the training plan wants you to to hit the power target. Say the leg balance went to 55:45 then you be having an easier workout than intended.

Say you leg balance changed at high power outputs than what it was during the FTP test. Now your sprint intervals or VO2 max workouts are harder or easier than they should be and you are training too hard or not getting enough benefit.

Now you may well accept that this could be the case for you and keep using a single sided power meter because it is good enough for you.

I am just showing how a single sided power meter may not give consistent results . It is just something to consider if you are thinking about buying a single sided power meter. Consistency is what really matters for training, not what the numbers actually are.

Of course you may well have a consistent leg balance but there is no way to know without dual sided power meters.

There's a lot of saying there.

Say your balance doesn't shift that much ?

FTP isn't 100% exact so even if you are a bit over or under - I'd not worry about it.
Maybe you could have pushed a little harder on the test. Maybe you needed to pace yourself better.

I think single sided would be fine for 99.9% of riders.

john_dixon

I recently fitted a stages L/R PM to my bike and the balance varies considerably! Low cadence, like starting off, can be 100/0 as I stand on each crank but on the road it is maybe 45/55 either way but generally close enough not to make me worry.
Still getting to know the meaning of the information but feel it is worth having.
I'm just an enthusiastic amateur but a bit of a geek with numbers!

wongataa

fenix said:

There's a lot of saying there.

Say your balance doesn't shift that much ?

FTP isn't 100% exact so even if you are a bit over or under - I'd not worry about it.
Maybe you could have pushed a little harder on the test. Maybe you needed to pace yourself better.

I think single sided would be fine for 99.9% of riders.

If you leg balance is stable then a single sided power meter is perfectly fine for training. The question is how do you know that your balance is stable?

I agree that for many people single sided is fine.