• This topic has 1,316 replies, 5 voices, and was last updated 4 years ago by DanW.
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  • Which power meter – Stages or Power2Max?
  • bob_summers
    Full Member

    Those are the two on the shortlist, as I can’t spend SRM money, and don’t think a powertap would work for me (switching wheels too often). On top of that, I’ve broken my crank so was thinking of killing two birds with one (expensive) stone.

    Has to work with Campagnolo 11spd, BSA BB, Garmin Edge 500. I was leaning towards a P2M in Rotor 3d flavour, but I know a few here rate the Stages (would mean buying a FSA Energy or SLK crank). I’ve read the in depth reviews on DCRainmaker but none the wiser really.

    njee20
    Free Member

    The Stages is lighter and cheaper, but that’s it. If you’re not too worried by either of those then I’d get the P2M all day long, much more accurate, none of the reliability problems, more data – left:right splits and such.

    The-Swedish-Chef
    Free Member

    Stages doesn’t work with carbon cranks, so that only leaves Campy Athena as an option for 11sp.

    Stages would be my choice though, especially as Sky are now them and this will hopefully lead to better development etc

    mrblobby
    Free Member

    Been thinking about this a while too and I’m tending towards a P2M with the Rotor crankset. Accuracy and reliability being the main points.

    bob_summers
    Full Member

    Doing the maths, I don’t think there’s a lot in the price, being as I need a crank anyway. FSA Energy + Stages + BB is about 850EUR, same as a P2M Gossamer (which is a boat anchor) – another 100€ gets the Rotor version. Could be worth the extra money?

    SwedishChef, no Campag options at all for Stages, but the FSA cranks would work fine.

    barrykellett
    Free Member

    Power2max without a doubt.
    Why measure power on only one side make assumptions when you can have the real McCoy for almost the same money.

    Speaking as a stages owner

    LS
    Free Member

    P2M every day of the week! I’ve got the Rotor 3Ds and it all works perfectly (long-time but now hacked off Powertap user here), every time.
    Stages is far too much like guesswork for me.

    reggiegasket
    Free Member

    If I had the money to drop it would be a P2M for sure.

    bob_summers
    Full Member

    Are you using the older version P2M LS? If I understand correctly, the old version (ie the triangular pod) now has the new firmware, so paying extra for the Type S only really saves weight, you don’t gain any functionality aside from being able to fit oval rings.

    njee20
    Free Member

    Just went and looked at the UK RRPs for Stages, OOF! Definitely P2M!

    mtbmatt
    Free Member

    Why measure power on only one side make assumptions when you can have the real McCoy for almost the same money.

    P2M is only one sided… as is SRM and Quarq.
    I know the measure things differently, but one sided none the less.

    njee20
    Free Member

    P2M is only one sided… as is SRM and Quarq.

    Not really – the strain gauges know how hard you’re pushing with the left leg because of the deflection at the spider. You can ride a P2M/SRM/Quarq one legged (with the left leg) and still get a reading. A Stages has absolutely no idea what your right leg is doing, just assumes it’s the same.

    mtbmatt
    Free Member

    Yes, but it sits on one side – not both, like Garmin Vector for example.
    I am just being a pedant, obviously 😉

    DT78
    Free Member

    Friend has stages, had to go with a rival crank for his red chainset. He has had it a couple of months now and rates it.

    DanW
    Free Member

    Possible weaknesses of P2M are that left/ right balance is still an estimate and based upon a series of assumptions (although less than that of the Stages assumptions). Also, possible servicing and warranty help- not sure how that looks in the UK at the moment.

    Stages seems nice, light and convenient if you already have cranks but much less of a bargain if you need to buy the cranks too. The main selling point of Stages is price IMO and when it starts to get up to P2M/ Rotor money (and you have to add a heavier alu crank than you’d probably rather run then the weight advantage disappears too) then it looks a whole lot less attractive.

    Have you considered the Rotor Power Crank? It is the only set up to actually measure left/ right independently which gives you metrics like Torque Efficiency and Pedal Smoothness. Probably doesn’t mean much in the real world and for day to day use but perhaps a nice addition to have “just because” considering the unit is the same price as a P2M set up.

    EDIT: Beaten to it on the left/ right assumptions of spider based power measurement like P2M/ SRM 😀

    mrblobby
    Free Member

    Rotor Power Crank

    Quite a bit more expensive than a P2M though.

    bob_summers
    Full Member

    As above – Stages is one sided and simply doubles the numbers, whereas P2M is both-sided (it makes a guess at L/R balance). Both are compromises, but the P2M seems less of one.

    In my case, I don’t envisage needing to know my pedaling dynamics or smoothness. I was happy just having overall power last winter on the turbo (albeit virtual) and would like similar on the road too.

    The Sky tie-in surprises me – with their marginal gains etc, it’s strange that Froome would be training with a compromised design. Either his L/R balance is exactly 50/50 😉 or Stages have got something interesting in development.

    DanW
    Free Member

    Quite a bit more expensive than a P2M though.

    Rotor can be had for ~£1200… how much are the cheapest P2M? ~£1000? It isn’t a SRM-type jump in price but true it looks to be a few hundred more

    carbonfiend
    Free Member

    I dare anybody to tell me the power output difference between left & right leg and if it actually makes any difference. Also fluctuations in power are so random as the terrain you ride changes so often that’s why Coggan & Allen came up with normalized power. It’s being consistent that’s important and I have used stages & SRM with no difference in data.

    bob_summers
    Full Member

    Rotor’s too much for me, looking to spend less than a grand (eur) inc rings and bb.

    njee20
    Free Member

    Either his L/R balance is exactly 50/50 or Stages have got something interesting in development Sky are running power meters on both cranks.

    Maybe? Anyone checked?

    The main selling point of Stages is price IMO and when it starts to get up to P2M/ Rotor money (and you have to add a heavier alu crank than you’d probably rather run then the weight advantage disappears too) then it looks a whole lot less attractive.

    I was shocked to see that a Dura Ace 7900 or 9000 Stages is £800, considering you can’t get a chainset with a LH crank so you then have a spare that strikes me as excessive. A Rotor 3D P2M is only £750 for both cranks and the spider.

    bob_summers
    Full Member

    Sounds like you needed a spare LH crank arm with the teething problems they had!

    I’m starting to think the Stages would be perfect for me but is about 200€ overpriced.

    LS
    Free Member

    Are you using the older version P2M LS?

    Type S – it looks nicer 😀
    Toying with the idea of putting the original type on the winter bike to replace my last working PT before it dies.

    mrblobby
    Free Member

    The Sky tie-in surprises me – with their marginal gains etc, it’s strange that Froome would be training with a compromised design. Either his L/R balance is exactly 50/50 or Stages have got something interesting in development.

    Is a little surprising, I’m guessing they are getting paid to use/market them. Though don’t BC use wattbikes, so maybe they do most of their testing and analysis on those.

    Must admit I’m tempted by a Stages as a cheapish option. I have the powertap on the turbo for power based intervals where I’d want something as accurate as possible. The Stages for training rides and club runs would be handy for some analysis, working out TSS etc. Or I may move the power tap onto the training bike and get a Kickr for indoors. Argh too many (expensive) options!

    bob_summers
    Full Member

    No Drive side Stages on Froome’s bike at the Dauphine 😀

    DanW
    Free Member

    The Sky tie-in surprises me – with their marginal gains etc, it’s strange that Froome would be training with a compromised design. Either his L/R balance is exactly 50/50 or Stages have got something interesting in development.

    It was costing Sky a fortune to buy the required number of SRM’s and not all team members were able to be supplied with their own units plus it is difficult to swap between the number of bikes the pros use. I guess Stages makes the mechanics life easier and remember too that Stages are reported to have paid Sky a 6 or 7 figure sum of money for the privilege of appearing on the “marginal gains” team. No-one really knows if L/R balance is important and I know from my own riding on an Ergo that my L/R balance was only 49/ 51 when recovering from knee surgery. I would have thought the pros are far smoother and balanced than that! On top of aaaaallll of that some SKY guys have been pictured with blacked out SRM spiders, just as some of the Garmin guys run dummy Vector pods and blacked out SRM’s…. nothing is clear cut 😀

    mrblobby
    Free Member

    No Drive side Stages on Froome’s bike at the Dauphine

    Can you tell from that photo? Can’t really see the inside of the NDS crank.

    thisisnotaspoon
    Free Member

    I was shocked to see that a Dura Ace 7900 or 9000 Stages is £800, considering you can’t get a chainset with a LH crank so you then have a spare that strikes me as excessive. A Rotor 3D P2M is only £750 for both cranks and the spider.

    What bugs me is there’s (AFAIK) not much difference between any of the shimano LH crank arms, all the tech seems to go into the right and the rings, yet the price difference between the 105 crank and a DA crank is almost as much (£200 Vs £270) as a DA chainset!

    Do stages have to pay full RRP for chainsets then bin the right hand arm? The price wouldn’t be hard to swallow if it included the RH crank too! Or they had a UK distributor you could send LH cranks off a new bike to and have them added.

    njee20
    Free Member

    I’m starting to think the Stages would be perfect for me but is about 200€ overpriced.

    I’m sure the initial pricing was about $700 for a Dura Ace one, which seems about right. Seems now it’s decidedly mid-ranged, more expensive than Powertap, P2M, pushing Quarq too by the time you factor in the chainset.

    Toying with the idea of putting the original type on the winter bike to replace my last working PT before it dies.

    How do they die out of interest? Mine is about 5 years old now, eats bearings, but other than that and batteries it’s never missed a beat, gets completely neglected too!

    What bugs me is there’s (AFAIK) not much difference between any of the shimano LH crank arms, all the tech seems to go into the right and the rings, yet the price difference between the 105 crank and a DA crank is almost as much (£200 Vs £270) as a DA chainset!

    Do stages have to pay full RRP for chainsets then bin the right hand arm? The price wouldn’t be hard to swallow if it included the RH crank too! Or they had a UK distributor you could send LH cranks off a new bike to and have them added.

    Agreed, in the US you could buy a whole chainset, which lessens the blow a little if you’re building a bike or sommat.

    barrykellett
    Free Member

    mtbmatt – Member
    P2M is only one sided… as is SRM and Quarq.
    I know the measure things differently, but one sided none the less.

    it might be on one side – but it is not measuring one side.

    I’m sure you can grasp the difference in measuring torque on a crank arm as opposed to the crank spider and are just trying to stir the pot with word play

    mrblobby
    Free Member

    How do they die out of interest? Mine is about 5 years old now, eats bearings, but other than that and batteries it’s never missed a beat, gets completely neglected too!

    Was going to ask the same thing. Mine gets neglected and has been faultless. Though it does pretty much only get used indoors!

    Do stages have to pay full RRP for chainsets then bin the right hand arm?

    Haha, I did wonder exactly this a few weeks ago!

    BIGMAN
    Free Member

    I am selling an as new Quarq in classifieds!

    njee20
    Free Member

    Though it does pretty much only get used indoors!

    Whilst mine got ridden through at least 5 hub-deep floods over winter with nary a sniff of trouble!

    carbonfiend
    Free Member

    Sky don’t use Watt bike they do their testing on the bikes in the lab on a giant treadmill with rider strapped into a hoist. As I mentioned left or right isn’t relevant it’s consistency in readings from Normalized/AVG power avg 20 min etc & % of FTP and Sky will also be using quadrant analysis.

    The-Swedish-Chef
    Free Member

    My PT died this year, directly after the winter indoor season.

    Still gives out readings that are correct, but will suddenly spike or drop off completely. Needs to be looked at by a PT specialist as the LBS can’t do anything.

    Contacts anyone?

    DanW
    Free Member

    A Rotor 3D P2M is only £750 for both cranks and the spider.

    Wow! That really is fantastic value (comparatively). P2M all the way then 😀

    Do any of the P2M MTB versions sell for that sort of money too?

    I was shocked to see that a Dura Ace 7900 or 9000 Stages is £800

    Completely agree. Selling them for £5-600 would be far more attractive. I think it is partially due to the distributor in the UK (a bit like the US and UK price for Santa Cruz stuff) where the Stages crank I was looking to buy is $700 in the US but Saddleback quoted me £850! Also, potentially high costs to Stages to acquire individual crank arms from manufacturers who may have existing agreements in places with other power meter manufacturers. Some companies also seem to penalize the UK compared to Europe for some reason- the LBS was complaining that SRAM in particular set the price to the distributor much higher in the UK than the EU which means LBS’s and even online shops that can only source stuff from the UK distributor can’t get anywhere near competing with the EU, let alone the US.

    it might be on one side – but it is not measuring one side.

    I’m sure you can grasp the difference in measuring torque on a crank arm as opposed to the crank spider and are just trying to stir the pot with word play

    No, spider based measurements measure net torque produced. You can’t measure if the left and right legs are working against each other at any stage for example. A true left and right measuring system like Rotor or Garmin measure the actual power produced at either side to be able to then display net power produced as well as what they call “torque effectiveness”. It isn’t just word play but whether it matters in the real world is another thing

    DC probably explains better than we can 😀

    Estimated Left/Right Power: This became all the rage over the last 18 months or so, starting with the SRAM/Quarq RED unit offering left/right power. That platform works by essentially splitting your crank in half and assuming that any power recorded while pulling up is actually coming from the left side, whereas pushing down is from the right side. Thus, an estimation. It’s good, but not perfect. Note that even with true left/right power (below), there’s actually very little in the scientific community around what to do with the data. While you may think that perfect balance would be ideal – that hasn’t been established. And some that have looked into it have found that trying to achieve balance actually lowers your overall output. The only thing folks agree on is that measuring left/right power can be useful for those recovering from single-leg injury.

    Actual or True Left/Right Power: This is limited to units that can measure your power in more than one location. Thus why we see it on pedals, as well as the more expensive crank-arm based power meters. You can’t measure it directly at the spider, instead you have to measure it upstream of that.

    Pedal Smoothness & Torque Efficiency: These two metrics are just making it into the high-end power meters which contain true left/right power measurement. Today that’s only the Rotor and Pioneer units, but Garmin has stated they’ll be adding it down the line via firmware update.

    njee20
    Free Member

    Do any of the P2M MTB versions sell for that sort of money too?

    Sadly not €1230 for a Rotor 3D, presumably as they don’t do the volume.

    A bit of Googling yielded a Dura Ace Stages for £528, plus shipping, or £792 including the chainset. Bit more like it! On closer inspection they (along with several others) won’t ship, which is a pain. Stages trying to close that door I wonder?

    carbonfiend
    Free Member

    This is a long read but if you stick with it is really helpful http://www.dcrainmaker.com/2013/06/stages-review-update.html

    bob_summers
    Full Member

    The Sky Stages have blue covers so you can just about make it out on his NDS crank, but nothing on the DS (referring to the pic on p1)

    The Rotor thing is odd too. They seem to be selling OE cranks without spiders or rings to P2M, yet are also trying to flog their own PM system for a few hundred more.

    mrblobby
    Free Member

    680 quid here which is a bit better than 800 quid. TBH I’d probably just get the 105 version, I think they fit fine on Ultegra and DA chain sets, it’s only 530 quid, and I’d probably do a TiRed and wrap it in an inner tube anyway.

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