Power Meters

deconduo

Any recommendations for a reasonably priced power meter?

I had a read of this, though its 2 years old at this point and a bit US centric - https://www.dcrainmaker.com/2018/11/power-meter-buyers-2018.html

I don't think I care about having 2 sided - so it looks like the 4iiii ones are good value and reasonable easy to access over here. Other option might be the Garmin 3S pedals, though they are a bit more expensive.

Anyone have suggestions on anything else? Or know of any good deals to watch out for?

Cheers

Daroxtar

I have an FSA Powerbox. Picked it up from bike24 for around €500. Very consistent, can't fault it. https://www.bike24.com/p2307711.html?q=FSA+Powerbox

dahat

Stages have reduced all prices just this week.

The whole left side /dual side can be done again but for the budget conscious LHS are reasonably priced these days.

If you want dual the the Favero pedals are getting rave reviews for €699 ish, likely to upgrade to these myself all going well this year.

koutoubia

I have a set of Favero Assioma duo.
The right pedal started giving bizarre readings around Sept.
Contacted Favero and they ran a diagnostic on it remotely and once they were happy they hadnt been crashed they sent a new axle and power pod. Just had to pay for shipping.
A lad who works in the local bike who is an A1 rider had the Vector 3s and was driving him mad with dropouts.
Gave him a lend of my Assiomas for a few weeks and was happy enough that he bought a set!

TGD

Daroxtar wrote: »

I have an FSA Powerbox. Picked it up from bike24 for around €500. Very consistent, can't fault it. https://www.bike24.com/p2307711.html?q=FSA+Powerbox

But an upgrade to double sided reading costs more - around 50 quid if I remember correctly.

North of 32

I can also recommend Favero. I have the Assioma Uno. I got it new for 395€. I find the readings consistent, very easy to set up (particularly if you rent bikes while on holiday) and has great battery life.

G1032

Any recommendations for a power meter for a CAAD12?

Looking for budget option more than expensive one!!

Cleat system is Shimano

Chain set: Cannondale Si, BB30a, FSA rings, 52/36

Also don't think I'll be converting the BB to GXP.

JimmiesRustled

G1032 wrote: »

Any recommendations for a power meter for a CAAD12?

Looking for budget option more than expensive one!!

Cleat system is Shimano

Chain set: Cannondale Si, BB30a, FSA rings, 52/36

Also don't think I'll be converting the BB to GXP.

FSA powerbox is a BB30 spindle so it'll fit within the BB30A frame of the CAAD 12. You'll need a few shims but that's it. It's easy enough once you've it setup. Have it on mine.

Macy0161

TGD wrote: »

But an upgrade to double sided reading costs more - around 50 quid if I remember correctly.

Think it's only really an estimate though, as it records total power, if I remember correctly?

I've 2 4iii's that I got on Probikekit - one 105 and one ultegra (I did used to swap the ultegra one, but saw a great deal on the 105!). Total or dual sided power is obviously better, but I've found them to be consistent against my Hammer and RPE/ Heart Rate.

I'm hoping for a raft of spd pedals now it's apparently out of patent, and the Assiomas hack seems to work for GP Lama (so I'd expect Favero to be quick out the blocks!).

Daroxtar

TGD wrote: »

But an upgrade to double sided reading costs more - around 50 quid if I remember correctly.

I don't know if dual sided is really that necessary. A fair few of the pro teams still use single sided. I'm a slightly overweight, bald, middle aged asthmatic. It's enough to know I'm weak without my bike telling me I'm lop sided as well

Statler

Big reductions on Stages units recently, third generation units apparently solve all issues with previous ones... https://www.stagescycling.eu/

Edit: apologies half asleep didn't notice dahat's post above...

barleyman

These are excellent (p2m type S), have two of them and never had a problem. Have series 2 vector pedals and nothing but problems. Think series 3 has a problem with battery discharge.

Seem very good value in the sale if you can pickup a rotor 3d+ crank handy (think will work with 3d30 also but would need to confirm)

powermeter + praxis rings + rotor bolts €390

https://www.power2max.com/en/product/type-s-road-rotor-3d-power-meter/

Crocked

Daroxtar wrote: »

I don't know if dual sided is really that necessary. A fair few of the pro teams still use single sided. I'm a slightly overweight, bald, middle aged asthmatic. It's enough to know I'm weak without my bike telling me I'm lop sided as well

The Powerbox is total power as it's reading from the spider.

The "dual sided" bit is just them estimating the split between left and right, no-one really needs that anyway so no point on spending the extra money for that "service"

Pedals and crank based need to be dual sided to get total power. Dual sided crank based options which use Shimano cranks don't work anyway so avoid them.

Quigs Snr

Crocked wrote: »

The Powerbox is total power as it's reading from the spider.

The "dual sided" bit is just them estimating the split between left and right, no-one really needs that anyway so no point on spending the extra money for that "service"

Pedals and crank based need to be dual sided to get total power. Dual sided crank based options which use Shimano cranks don't work anyway so avoid them.

Its also just a power2max ng eco in disguise isnt it ? In which case they really are very good.

Crocked

Quigs Snr wrote: »

Its also just a power2max ng eco in disguise isnt it ? In which case they really are very good.

Thats my understanding too. I thought some were mixing up reporting left/right balance and measuring total power.

harringtonp

I've had a P2M for over 6 years which was switched regularly between bikes and still going strong. Last year invested in a 4iii which I keep on the race bike (no extra weight) and now keep the P2M on the winter/training bike.

IMO your best options are Powerbox, P2M for reliable dual sided or 4iii/later stages for something lightweight and budget friendly.

Decided to keep clear of pedals myself, just heard too many stories and like flexibility in choosing cleats/pedals

tuxy

4iiii single side give very accurate readings on the left side for a reasonable price.
Of course if you have a bad imbalance this may be no good but if not it's a cheap way to get into training with power.
Mine has worked flawlessly despite being used in many torrential downpours.

CramCycle

I think I am going to go with the 4iiii single side. any negative reports from them or is everyone happy?

RobFowl

I have Stages single sided and they seem fine, that said I just look at the numbers in the same way I do the sky. Look nice at times, frightening at other times......

harringtonp

CramCycle wrote: »

I think I am going to go with the 4iiii single side. any negative reports from them or is everyone happy?

I'm generally happy though compared to p2m I've had to take about 10 watts of interval sessions. It could be a left leg thing but using it on the turbo recently I noticed cadence dropouts. It's not really a problem for power as whatever behaviour it exhibits seems to be at least consistent

I haven't heard complaints from anyone else about them and they do just work.

P2C

Have had a few PM. A couple of cyclops hubs and caused nothing but hassle. Bought a basic sram in 2013 and have used it since with no problems. I know five of us in the club got them around the same time and there still all going strong. A few have p2max and no problems with the either.

Gallant_JJ

I had the vector pedals for over 3 years with nothing but problems. Had 2 warranty replacements, each set was worse than previous. When they were reading I never had a l/r discrepancy beyond 49/51, so recently purchased the 4iiii. Have it about 4 weeks and very impressed. Simple and functional.

Macy0161

CramCycle wrote: »

I think I am going to go with the 4iiii single side. any negative reports from them or is everyone happy?

No issues with mine. Tested them initially against my hammer, and they measured the same.

Like I said earlier in the thread, I was happy enough with the ultegra one I got first off, that I ended up buying a second 105 one for another bike to save swapping!

Chips Lovell

CramCycle wrote: »

I think I am going to go with the 4iiii single side. any negative reports from them or is everyone happy?

This is a post I wrote about single sided power meters a few years ago. Wasn't really convinced they're worthwhile.

Chips Lovell wrote: »

The issue with single-sided power meters is that there's two many unknown variables for them to be useful.

Here's a file from a race I did last year.



As you can see, the L/R shifts around a fair bit, moving between 50/50 and 60/40, with a few spikes even larger than that. If I'd been using a single sided power meter it would have largely moved between accuracy and lowballing my numbers, with odd overstatement.

Now, here's a better illustration, a file where I did three 5 minute hill intervals.



What does it tell you (aside from the fact that I did the first one harder than the other two)? That for sustained Z5 type efforts my left leg was dominant, but for anything below that I seemed to favour my right.

What does this mean then for using a single-sided power meter? Well take a hypothetical rider who, like DC Rainmaker, has a largely 50/50 balance up to and including FTP. So they get a single sided power meter, do a proper test and find out they've an FTP of 350w. They then go set their zones based on this number.

The problem then is if their balance varies based on intensity or fatigue. Say our rider decides to do 4x 5 minute Z5 intervals. According to the zones he's worked out, that's something like 370w to 420w.

Our rider decides to attempt to average 400w for each interval. But, what he doesn't know is that above FTP, his L/R balance is more like 55:45. Because the left side power meter just doubles left sided power, he's doing 200w with his left leg to display an average of 400w. But he's doing 245w his right leg, meaning is real power output is more like 445w, which is well into Z6. What happens? He goes too hard and can't complete the set.

Or it could be the case that his L/R balance is 50/50 when he's fresh, but as he fatigues it drifts in one direction, meaning he starts actually doing 400w but then has to up his effort beyond 400w as he tires in order to keep the display reading 400w. After a few failed attempts at a set, he's going to start lowballing the initial intervals in order to sustain (what he thinks) is the same level of effort at the finish.

€400 is serious cash and I don't think you'd be getting much in return. With that amount of uncertainty, i can't see it providing any advantage over perceived effort or HR based training.

Macy0161

I don't think anyone would argue that total power is better, but personally I came to the conclusion that having a consistent (if not necessarily accurate) was more important. I took on board the need for total power, tried in vain to save enough for a total or dual power source, and probably wasted the guts of a year when I could've had a consistent source.

It's not just the power meter, once you start getting into bottom brackets, chain rings etc., especially across multiple bikes.

Chips Lovell

To be clear, the conclusion I came to is that with a single-sided power meter, you risk having something that is both inaccurate and inconsistent.

harringtonp

You're analysis above is good and gives great insight. I agree with it in the sense that I prefer my P2M for training but when I do use the 4iii for intervals I find it way better than judging based on feel or HR. And at the end of a session with it I do feel the goals were accomplished, i.e steady state during and across the intervals and if VO2 failure or near failure at the end of the set

nilhg

Chips Lovell wrote: »

This is a post I wrote about single sided power meters a few years ago. Wasn't really convinced they're worthwhile.

While I don't really disagree with anything you said in the quoted post I think the weakness in your argument is that you're doing 5 minute intervals based on the result of a 20 minute FTP test. From what I'm seeing and reading many companies and experts are moving away from one straight 20 minute test to multiple shorter tests, Sufferfest 4dp for example. Those would surely pick up better that natural variability in a riders output at differing levels of effort.

Personally I moved from a singlesided meter for 3 reasons, the one I had, Avio Powersense has issues with battery life in the cold, it wouldn't fit my TT bike and I'm using oval rings and the only meter I could find that ticked all the boxes for me was the Assiomas, I bit the bullet and went Duo, they haven't missed a beat since I got them.

JimmiesRustled

nilhg wrote: »

While I don't really disagree with anything you said in the quoted post I think the weakness in your argument is that you're doing 5 minute intervals based on the result of a 20 minute FTP test. From what I'm seeing and reading many companies and experts are moving away from one straight 20 minute test to multiple shorter tests, Sufferfest 4dp for example. Those would surely pick up better that natural variability in a riders output at differing levels of effort.

That sufferfest 4DP thing isn't really all that new. Pretty sure Coggan brought it up before and training peaks (Wko) has, as far as I can remember, a power profile. As does golden cheetah as far as I'm aware

The problem with a lot of riders that I see, and I'm by no means an expert, is that they go out and test a 20 minute effort without any sort of clearing effort beforehand. They then get in their own head during a race when they look back and see they couldn't even hold their "threshold".

In any case, single leg power to me personally just wouldn't and doesn't work. I've had a good few leg injuries from other sports and as such my power isn't equal from one leg to another. It's not linear either. At 200w my power might be 52% 48%. At 300w it might be 55% 45%. At 350w it could be as high 60% 40%.


EDIT: Realised I'm pretty much saying the same thing as Chips in relation to R/L leg balance but I'll leave it up as another vote for total power.

Chips Lovell

nilhg wrote: »

While I don't really disagree with anything you said in the quoted post I think the weakness in your argument is that you're doing 5 minute intervals based on the result of a 20 minute FTP test. From what I'm seeing and reading many companies and experts are moving away from one straight 20 minute test to multiple shorter tests, Sufferfest 4dp for example. Those would surely pick up better that natural variability in a riders output at differing levels of effort.

This is an interesting point. It's been a few years since I was training very seriously. Coggan/Allen was my bible. My coach had me to regular 20 minute tests, supplemented by shorter, 6/7 minute tests and he'd get my zones from that. Everything went into Golden Cheetah and to be honest, what I could manage in real life usually closely lined up with the zones I had at the time.

In theory, you mitigate some inconsistency by doing tests across multiple zones, but that doesn't mitigate the issue of balance varying with fatigue levels I highlighted above.

JimmiesRustled wrote: »

The problem with a lot of riders that I see, and I'm by no means an expert, is that they go out and test a 20 minute effort without any sort of clearing effort beforehand. They then get in their own head during a race when they look back and see they couldn't even hold their "threshold".

Anecdotally, this seems to be a mistake a lot of people make. There's a temptation there to have as big a number as possible.

CramCycle

Chips Lovell wrote: »

Anecdotally, this seems to be a mistake a lot of people make. There's a temptation there to have as big a number as possible.

I'd be one, I found the max ramp test far more accurate (or at least it gave a far lower number)
With the 20 minute test I done half way through last year I should have been in A1/2 without much effort. My real world efforts disagreed with that assessment.