Considering getting 4iiii power meter for the road bike. Only planning on getting the nds crank one but some people seem to reckon one sided is fine and other people reckon it’s too innacurate. Any real life experiences.

IMO one sides is perfectly fine unless you are someone special and are really interested in the left/right balance. Had a stages for years and its been great

Depends if you are even legged power wise or like most of nature a bit asymmetric.

My power balance is quite good on the flat say 51% left 49% on the right (that’s pretty consistent across a few power meters). When I climb I become more right leg dominant I have seen 45% left 55% right on some big hill efforts.

The left side only power meter just doubles what it reads on the left crank. So may be inconsistent over reading on the flat if you ride like me and under reading on hills.

May be worth trying a friends power meter to see how balanced you are on varying grades. If you are pretty consistently even go got it.

Yeah it does seem to be the only way to know if you can get away with a single sided power meter is to buy a double sided power meter…🙄

As mrchrispy said also read, though this was a few yrs back now & I’m sure someone will be along pretty soon to correct me, that any power discrepancy between legs is so small it makes no difference to overall performance except at world tour sprinting levels. 🤷

The main use of a powermeter from a training perspective is to consistently measure how much power you are putting out – doesn’t matter if the actual power figure is 100% accurate or not. So just measuring one leg is fine.

If you want it for Zwift and you reckon your non-measured leg is stronger, then you better get a double sided one.

Yeah it does seem to be the only way to know if you can get away with a single sided power meter is to buy a double sided power meter…🙄

Most gyms have Wattbikes now (when they reopen…!).

I’ve used one-sided for years and they’ve been perfectly fine.

I’ll go dual-sided next but purely out of interest more than anything else.

Delta t is the interest.

Not the actual number

So long as you train to what the meter says and not what something you read on the internet says you should be achieving

One sided is fine, I used a single side crank arm until I broke my hip and then went dual sided to see if the break made any difference. Some days it varies some days I’m 50/50.

Single sided is a lot better than no power meter whatsoever.

And even with dual sided, there are probably more important things to worry about in the overall scheme of things than one leg being stronger than the other, or being slightly out. People trained to perceived exertion before power meters didn’t they and managed just fine!

They’re fine. As for you uneven-legged power? What are you actually going to do about it. I have both (Assioma Uno and an SRM). The dual sided as nothing.

It’s fun pedalling with one leg on the rollers watching power go to zero though.

It depends.  I have a Stages 1 sided, and it reads noticeably different from my Direto, and to a Drivo that I’ve tested on before.  It’s under at lower watts, then over at higher watts.

I don’t know if this is Stages, Direto, or me (my left/right balance changing as my wattage gets higher)

When I just had the Stages, it was great, all my training was consistent.  Now unfortunately I can’t use the Stages reliably so may sell it.  Most of my training is on the Direto, so that one will remain my reference, then I’ll use HR when outdoor.  That works better as I have a few bikes that don’t have a power meter.

Got smart turbo and thinking if the figure is going to be very different from that it kind of makes the whole thing a pain. Maybe I’ll just use power for zwift then just ride outdoors, means I can maybe buy a Dura ace crank instead of one sided 105 power meter.

I have left sided stages on all my bikes. Actually one of them has a dual sided stages but I want consistency between all of them so I switched the right side off. I don’t trust the right sided stages unit, it seems to under read so my l/r balance is off compared to a watt bike…and apparently it’s a known issue with shimano power meters

Pretty much every power meter uses some kind of approximation or estimation to give you a power number. As long as you use the same device with the same approximations then you’ll very likely be able to use it to train effectively. Even if your L/R balance changes with effort levels you’ll probably still be in the right zones and get the training benefit.

If you’re using it alongside a smart trainer then most of the apps allow you to measure the power on your PM and use that to control your trainer (TrainerRoad and Zwift do this better than Sufferfest).

I’ve had a couple of NDS 4iiii PMs but ended up getting a dual sided one. The readings told me I was pretty much 50/50 with good pedal smoothness and torque effectiveness. So basically I would have had accurate data with a single sided PM.

So if you won’t be satisfied unless you have ALL the data Then get a dual sided. If you just want to train with power, are fairly relaxed about any other metrics and don’t have a massive physical imbalance issue then get a single sided.

I’d say it’s worth it. Found the figures to be useful and sufficient. But then again I’m not an elite athlete. Definitely worth it for Zwift.

Not super fussed about it being exact, smart turbo has older bike on it so would be putting bike with power meter on it. Figures may well differ I guess. Read about Shimano double sided cranks not being the that accurate so hmmmmm

I have been using a single-sided 4iii since February. It has made a significant difference to my training compared to just using HR.

My power level fluctuates quite a lot in the real world as grade, wind and even tarmac quality changes. Even looking at 3s average power, it varies by +/- 15 watts I reckon when trying to keep to a specific number. I’m not sure I can improve on that much so a percent or two error in right/left balance isn’t going to worry me.

I’ve got 2 4iiii LH crank ones & like everyone else says they are fine for most of us. I actually found them quite useful for giving more accurate measurements for calories burnt (i’m an eater).
Started commuting to work a few years ago & couldn’t figure out why i wasn’t losing weight when i was burning so many calories. For my 15 mile commute;
Garmin calorie approximation 1100-1200.
Strava approximation 800-900.
Power meter 550-600.

Didn’t Team Sky use Stages for a while?

I have a 4iiii, does the job perfectly fine. They have less reported reliability issues than Stages too.

Didn’t weren’t Team Sky use sponsored by Stages for a while?

Subtle but important difference 😉

They were using the dual sided prototypes for a long time too.

Now they’re sponsored by shimano, but still mostly use stages power meters………….

I got suckered into power data obsession after buying my Direto turbo and bought a 4iiii at the wrong time for a bargain, paying £340 IIRC for the 105 5800.

But training by power was a game-changer for me in terms of improvement, as I drink far too much caffeine and stress easily, making heart readings even less useful than most find them. I’ve no idea if I have a power imbance between my legs, I’m right-footed and handed, but I’ve never used a dual side power meter and I never bothered paying for the Elite analysis tool back when I believed my Direto’s readings (as they were practically the same as my 4iiii early on, now the Direto is ~7% higher which is wrong unless I’m really heavily imbalanced to my right leg).

~£240 at mo for 105 7000 version at https://www.probikekit.co.uk/cycling-power-meters/4iiii-precision-2.0-3d-power-meter-105-r7000-black/12104435.html , very little point paying extra for Ultegra or DuraAce version.

Currently got an R7000 cranks but bike is getting upgraded to R8000, which would mean new crank and then left hand power meter. Wish 4iii would sell crank with left hand power only as it would work out a bit cheaper.