Home Forums Bike Forum Power Pedals – £1050 Really????

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  • Power Pedals – £1050 Really????
  • twonks
    Full Member

    Think the basic SPD-R pedal it’s based on is about £850 and they charge a tidy sum for the mtb SPD body.

    That bit is sort of understandable as there will be by far more road based cyclists interested in power meters, hence manufacturing costs for the mtb bodies is disproportionately high.

    Still a huge amount of money for something that can and does get smacked on rocks every few rides.

    I fancy a power meter for my hard tail. Not sure why tbh as I don’t train as such – just another metric to look at and surmise with a post ride tea whilst analysing Strava.

    Not paying anything like that for one though, so at the moment it is definitely a desire rather than must have.

    malv173
    Free Member

    Oof!

    They are meticulously designed and rigorously tested though. That can’t be cheap 😅

    Plus they are compatible with Shimano’s SPD sandals. Can’t put a price on style.

    continuity
    Free Member

    If you buy favero assiomas you can swap the pedal bodies for SPD’s.

    thisisnotaspoon
    Free Member

    Surely the price has to come down at some point?

    Back at university 15 years ago I was building “power meters” to try and integrate them into hockey sticks, it didn’t work, but the actual devices aren’t £1000 of R&D and voodoo. I think our entire budget was about £250 including building the thing from scratch, and we had a working power meter, it just wouldn’t stick to carbon fibre (same reason most brands still won’t sell you a carbon crank based power meter despite some of them promising it).

    <£250 power meter, comes in MTB bolt patterns and there’s even DC Rainmaker mini review somewhere where it works fine baring a few firmware glitches (which apparentlyngot fixed).

    Who’s still paying SRM £1k+ prices?

    teamslug
    Full Member

    I’ve got 2 Sigeyi crank power meters. Look same as XCadey. Both imported via their shop. Worked out at just over £300 each….”what about warranty?”you say. One of mine stopped charging after a year so I reported via sigeyi support page. I was sent another in a week and asked to post broken one back. Better and faster response than a lot of UK based companies. Both are with a few watts of my Elite Direto turbo trainer. I get the idea of pedal PM on a road bike but as pointed out above I ground my pedals pretty regularly too.

    spxxky
    Full Member

    Thanks Mister-P… Now I can get two sets LOL

    petefromearth
    Full Member

    I’m definitely not the target market for this product as I’m not one for gadgets on my bike

    But I can’t see any advantage in measuring torque from pedal force, compared to other methods

    And it surely compromises the pedal in other ways (cost for a start) due to cramming the load cells and other gubbins into such a tiny space

    Maybe it’s a way to get round competitor’s patents? Or to keep Garmin users buying their expensive hardware?

    Just strikes me as a very dumb idea for a product IMO

    DickBarton
    Full Member

    The original link is for the double pedal power meter pedals, so you can find out which leg is stronger, they do a single pedal version…but it isn’t much cheaper!

    molgrips
    Free Member

    I think our entire budget was about £250

    How much did your development and testing team cost? What about customer service, support, marketing, management, building and site costs? How much did your manufacturer what up front for the investment at scale? How much contingency did you need to buffer risk? How much markup from your dealers and distributors?

    Garmin don’t price gouge, I don’t think, because they sell a lot of basic stuff for a good price. As a big company I’m sure they’ve looked at demand and what people will pay. Re pedal meters, I’d use them because they can be easily swapped between bikes, and I could run a choice of cranks. And the sort of rider who really needs a power meter is probably training and they probably won’t be riding the sort of trails where you can’t avoid smacking pedals.

    5lab
    Free Member

    it does seem expensive when the new rival cranks add a power meter for £230 (rrp – I guess that’ll be ~£150 after some discounting). Only single-sided mind

    thisisnotaspoon
    Free Member

    How much did your development and testing team cost? What about customer service, support, marketing, management, building and site costs? How much did your manufacturer what up front for the investment at scale? How much contingency did you need to buffer risk? How much markup from your dealers and distributors?

    You’re trying to tell me that Garmin, manufacturing them in big numbers has a higher cost per unit than building one prototype from scratch?

    wbo
    Free Member

    No, I think he’s pointing out your £250 quid isn’t a real comparisom as you don’t include wages, profit, warranty claims , rent for the building, taxes so and so forth. Garmin aren’t a charity at the end of the day

    Plus you admit yours didn’t work. So how much to make it work? How far from being a power meter stuck on a stick to a marketable item?

    Garry_Lager
    Full Member

    I’m definitely not the target market for this product as I’m not one for gadgets on my bike

    But I can’t see any advantage in measuring torque from pedal force, compared to other methods

    And it surely compromises the pedal in other ways (cost for a start) due to cramming the load cells and other gubbins into such a tiny space

    Maybe it’s a way to get round competitor’s patents? Or to keep Garmin users buying their expensive hardware?

    Just strikes me as a very dumb idea for a product IMO

    It’s the most versatile place for a PM as it is trivial to change pedals between bikes – having a PM on every bike would be very expensive, so pedal PMs are v popular for this reason. There is also the argument that it is the most direct measurement of power, compared to other positions on the bike, but that is minor compared to the versatility angle.

    Time will tell whether it is a dumb idea to have a PM in spds for mountain-biking – I can barely read the model name on my MTB pedals they are all that hammered. Reliability is huge for PMs and has plagued some road units – and that’s without banging them over rocks.

    petefromearth
    Full Member

    Versatility / swappability – good point

    It’s not the best place to measure power though. It’s just a pair of load cells at the end of the day. Measuring force applied through the pedals will also measure rider weight, and any dynamic effects (bumps etc). Those are not useful things to measure if you want the power, and it would then need clever algorithms to remove that noise. I’ll wager that makes it a less accurate measurement of torque too.

    You could say the same about having a strain gauge on the crank arms.

    If you want to actually measure power transmitted through the drivetrain then a strain gauge on the spider will give you the torque without the other loads. I.e. Like the SRM ones or Xcadey above

    molgrips
    Free Member

    Measuring force applied through the pedals will also measure rider weight, and any dynamic effects (bumps etc)

    So would it at the cranks – although not at the spider. But the spider based meter can only be single sided.

    If they can be shown to be accurate, then that’s the bottom line regardless of whatever algorithm they’ve had to create.

    Re cost, it’s well known that most stuff isn’t sold on a cost-plus basis. So the profit margin on high end stuff is bigger because it can fund more competitive pricing on low end stuff which then builds market share.

    Oh and lastly – you could swap the same pedals between road and MTB too, and I think this is the only product I’ve seen that can do this no?

    twonks
    Full Member

    Not seen them before but, have just ordered one of the X-Cadey power meters to go in my Dub crankset.

    For £230 and from Amazon it’s an easy sell. If it doesn’t work sufficiently well it will be easy to send back.

    r8jimbob88
    Free Member

    I sold two random number generators, sorry I mean Stages power meters…. to fund a pair of Assioma Duo’s. Takes 60 seconds to swap between bikes and a further 60 seconds to swap pedal bodies to SPD. Still expensive at £700 but becomes much more attractive when you have multiple bikes.

    swavis
    Full Member

    But the spider based meter can only be single sided.

    Want to think about that a little longer? 😉

    Granted you won’t be able to tell left from right but it will measure from both cranks.

    DickBarton
    Full Member

    Which XCadey spider did you get for the DUB cranks? I’m slightly curious but not sure which size to get for mine (will need to do some more looking to check sizes).

    thisisnotaspoon
    Free Member

    Plus you admit yours didn’t work. So how much to make it work? How far from being a power meter stuck on a stick to a marketable item?

    We were measuring the force in hockey sticks, but basicly came up against the same issue that most of the crank based systems claimed to be able to resolve, then never did. That composites bend in odd ways and go soft/delmainate over time. Which is why they were only available on Shimano, cannondale, and lower tier Sram and FSA cranks for long time. This was 2007 ish, so a few years before Stages developed it. Im curious to know how they did eventually get it to work on carbon.

    The system worked, in the sense it gave you a reading from the strain gauges to a computer. Just not to give useable data in the application intended. The aluminium version was fine, but no one used aluminium sticks anymore.

    If it had been a few years later we could have stuck a render on Kickstarter and probably made some money 🤣

    But the spider based meter can only be single sided.

    I think the missing nuance is a spider measures net torque with one strain guage. A crank or pedal based system needs either two sensors and then take the net of the two to subtract the bumps, pumping etc. Or do what the one sided ones do and deduct the downward force from the upcoming pedal on the side they do measure.

    molgrips
    Free Member

    I hadn’t seen those XCadey ones – they look great and cheap.

    footflaps
    Full Member

    A crank or pedal based system needs either two sensors and then take the net of the two to subtract the bumps, pumping etc.

    It only needs two if they want to measure each leg separately.

    I had the old Polar power meter which worked on chain tension / resonant frequency of the chain via Hall Effect transducers – they could split out L/R leg imbalance from the one sensor (although not sure you knew which was which).

    thisisnotaspoon
    Free Member

    It only needs two if they want to measure each leg separately.

    I had the old Polar power meter which worked on chain tension / resonant frequency of the chain via Hall Effect transducers – they could split out L/R leg imbalance from the one sensor (although not sure you knew which was which).

    Measuring chain tension is just the same as measuring the torque in the spider, just via a different method.

    The L/R measurement though is open to interpretation somewhat.

    The crank (or hub, or chain) based systems are measuring the net torque on that sides power stroke. I.e. torque on the spider = force on pedal A – force on pedal B (multiply by pedal velocity to get power).

    When you have two pedals, or a dual sided crank based system you can then measure the power delivered on the downstroke on pedal A, then subtract the power absorbed by foot A on the upstroke to derive a true figure for the power on that side each revolution. Whereas single sided ones have to assume both are even in both directions (not just the pressing).

    Pedals can then go one step further and measure efficiency as they can see direction the force is applied, whereas cranks can only measure in one axis. Although I don’t think anyone has found a use for that as a metric yet.

    So the L/R balance given by a spider or hub or chain based system is not completely comparable to the L/R balance given by a dual crank based or pedal based system. They’re measuring different things.

    twonks
    Full Member

    @dickbarton Hopefully I am getting this one below. Amazon don’t seem to list boost or non boost options so it is a bit of a gamble. I’ll see what turns up and if I can get it right with a chainring.

    https://xcadey.com/product/xpower-s-sram-3-bolt-104bcd/

    The configurator tool on their web site worked yesterday and doesn’t now. Probably not a good sign 😀

    Crankset is a 12sp Eagle X01 dub.

    Reading a slightly old review by GPLama on youtube suggests the Xcadey is ok but under reads a consistent 5 to 6%. I’m not really that bothered about ultimate power, more the development as I hopefully get fit after 15+ bloody years of not being so !

    EDIT. This is the Amazon link. Sram 3 bolt 104mm
    Edit edit. Stupid Amazon tries to link to Kindle page as above.
    Not sure if it is my browser or their problem, but it comes up in a Google search for £239.

    DickBarton
    Full Member

    Thanks…I’ve a Descendant eagle 7k dub boost, which I think is SRAM, but I need to check BCD size.

    molgrips
    Free Member

    Measuring chain tension is just the same as measuring the torque in the spider, just via a different method.

    They were highly inaccurate though as they also (I think) picked up the lateral tension in the chain caused by the chain line. You could be winching up a climb in the middle ring big sprocket, then change down to little ring and smaller sprocket to keep the same road speed and it would report 30% drop in power.

    You’re right about being able to compare power from each foot throughout the stroke though. This would allow you to measure how much parasitic drag is caused by your trailing leg which could be significant.

    thisisnotaspoon
    Free Member

    They were highly inaccurate though as they also (I think) picked up the lateral tension in the chain caused by the chain line. You could be winching up a climb in the middle ring big sprocket, then change down to little ring and smaller sprocket to keep the same road speed and it would report 30% drop in power.

    Yea, I meant in the general terms of how it deals with the data and L/R balance from the total.

    One cool thing I’d like to see/try is using the strain guage data when not pedaling to measure efficiency on a pump track or over jumps. Niche, but could be interesting for BMX racers.

    teamslug
    Full Member

    https://www.sigeyishop.com/

    If the xcadey is anything like mine from above it will be pretty accurate. I was within 2 or 3 watts with my wheel off turbo on a few different zwift and trainer road workouts. Average power and nominal power were virtually same. I got a sram and raceface cinch versions. Both were boost and easy to fit, calibrate and gps unit picks them up every time.

    twonks
    Full Member

    Bit of a bump and update for those interested.

    My X-Cadey from Amazon turned up early last week.

    Did as most (probably) do and connected it to power and connected it to their Iphone software whilst on my desk. Seemed to be ok but kept dropping out. Thought it might be because we have 2 turbo trainers in the house and a lot of other ANT+/BT devices and the user instructions say to give it a good hard stomp on the pedals before playing, so didn’t think much more.

    Installed it on the bike this morning. Everything fit as expected and the Hope 32T retainer ring went on perfectly.

    Tried to connect it to my Garmin 530. It would see the power meter and also cadence and speed sensors that are apparently in the X-Cadey but picked up as different sensors. However, nothing would actually work. The Garmin could not take control of the power meter to calibrate it.

    The phone software then also did what it did previously and kept dropping out.

    After 30 or 40 minutes messing around I gave up. Put the crank back together with it’s own ring and started the Amazon return process. That in itself looks like it will be a pain!

    What makes this even more frustrating is (because I’m daft) I also bought a Rotor 2INpower crankset last week. Installed that last week on my main bike. All went swimmingly and works 100% as expected. Of course it is considerably more expensive, even at the great price I got it – but it shows that you get what you pay for I suppose.

    sillysilly
    Free Member

    Cheers,

    Just gone for the 4iii. Cheaper than the Xcadey with that coupon and you get a spare crank arm.

    richardk
    Free Member

    Now that Favero supports Shimano (sort of), I’m tempted to order a set of second hand PD-R7000 SPD-SLs and a set of the Shimano spindles from Favero.

    Has anyone ordered from Favero to confirm if there are any customs charges to pay in the UK?

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