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  1. #1
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    Power2Max MTB Power Meter

    As my Powertap hub has died I've been trying to consider what may be a good replacement. The Power2Max MTB power meter looks like a possibility. One nice thing about it is that it uses an accelerometer for cadence so you don't need a cadence magnet attached to the frame for it to work.



    http://www.power2max.de/europe/en/Pr.../rotor-3d-mtb/

    DCRainmaker review of road version:

    http://www.dcrainmaker.com/2013/01/p...th-review.html

    Has anyone tried one and how does it hold up in bad weather? Riding in the UK getting soaked is unavoidable.

    For my bike I'd probably go for a Rotor 3D crank (alloy rather than carbon crank arms so can be welded and modified) in a triple chainset version with a 169mm q factor, allowing me to keep my current setup of 44/33/23 front chainrings.

    I have to use a modified left hand crank as I'm unable to use a normal length crank due to my knee not bending. I also use Rotor Q ring oval chainrings. Would a modified crank and oval rings result in inaccurate power readings?

    This picture shows my current modified crank, which is used with a Shimano Deore XT chainset. I'd have to get a new one made to match the Rotor cranks. It has a 75mm crank length and a 50mm swing crank. The right hand crank is a standard 175mm crank with no alterations.

    Swing crank explanation:
    http://www.highpath.net/highpath/cycles/swingcrank.html

    The swing crank allows you to pedal without bending your knee as much as normal.







    .

  2. #2
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    Wow, first time I see a swing crank. Very ingenious, I must add.
    My rides:
    Lynskey Ti Pro29 SL singlespeed
    GF Superfly 29er HT
    S-Works Roubaix SL3 Dura Ace
    Pake French 75 track

  3. #3
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    Paula Newby Fraser use to ride a set of funky cranks like does on her Triathlon bike..

  4. #4
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    Power2Max MTB Power Meter

    I've been doing a bit of reading up on Power2Max power meters. For the road versions you can buy just a seperate power meter spider and fit your own cranks and chainrings. The MTB versions appear to come fully assembled however.

    I found this quote:

    "I have a P2M on my road bike with Rotor 3D+ crank and O’Symetric chain rings. Works quite well although front shifting is a bit finicky. I’m contemplating getting a P2M for my MTB, but I want assymetric chain rings on that one as well. P2M told me all their MTB products only came with “pre-installed” chainrings as the power meter device (battery compartment?) was blocking access to (at least one of) the chainring bolts." Erik Wolla

    http://www.dcrainmaker.com/2013/08/p...atibility.html

    Ideally I want to use my own combination of chainrings (Rotor QRing 23T and 33T oval rings with a 44T round outer chainring.) I've emailed Power2Max to see if they can clarify this as it could be a lot of hassle if it's not possible to change chainrings without sending it back to the company.

    The other thing about Power2Max is that in order to buy direct from the European site they don't currently accept credit cards or Paypal. It seems that you have to pay by direct Bank Transfer instead.

    There are various German web shops, such as this one, where you can buy Power2Max with different payment methods but it does add a bit more complication.

    http://www.powermeter24.com/en/products/power2max

    This thread is a a bit long and rambling but has some relevant links and discussion about Power2Max:

    http://www.lfgss.com/thread98428.html

    Also:

    http://wellmt.wordpress.com/2013/05/...x-power-meter/

    .

  5. #5
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    Have you contacted Stages to explain the situation and see if they can do a custom powermeter for you? It seems like they should be able to put the powermeter on the DS instead of NDS, that way you could keep your existing NDS crankarm

  6. #6
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    Probably not much help but I've used the early road model for a few rides and found while yes it was good, it did what it was meant to it did have issues with tempreture change and recording a lower figure then the effort(s) would suggest. From what I understand this has been fixed by way of a firmware update and the later models are no longer suseptable to issues with tempreture change.


    Now the bit I might be able to help with, there is an NZ online shop that sells Power2max power meters, spiders, parts etc... I think they are the distributer in NZ but their pricing is quite competative and offer free shipping on orders over a set price (atleast to Aus), and you don't pay GST so it brings the price down (as does the US exchange rate).

    Power2max » Bikecycle
    Cul is a regretted trademark of the CulBaire Co'op Pty Ltd, as are his random ramblings and associated ********.

  7. #7
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    Power2Max MTB Power Meter

    The problem with the Stages power meter is that it measures torque applied to just one crank arm. It then doubles that torque figure to estimate overall power output, using the assumption that power output is equal between both of your legs. Because my power output is so uneven and imbalanced between legs Stages would display either an extremely low power figure (measuring left leg) or an extremely high power figure (if it were measuring the right leg). In order for a power meter to work for me it has to record power somewhere in the drivetrain. Crank spider, which records power produced from both legs (eg: Power2Max, SRM, Quarq) or at the hub (Powertap). The pedal based power meters (eg: Polar, Garmin Vector) require equal length cranks on either side, ruling them out too.

    This diagram is from the DCRainmaker Stages review:



    "As you can see, the normal pedaling is pretty similar to each other. As I shift into Right-leg heavy (well beyond normal right-leg heavy), you see the Stages power meter (which is left-leg measured), drop significantly. Again, this is an exaggeration of an imbalance for the point of this graph, but it shows the impact. Then, as I shift to left-leg heavy, you see that it substantially increases the measured total power well above what was actually being put out (which was hard-set at 150w).

    Next, as I unclip the left leg entirely the power drops to zero. In fact, the cadence also dropped out (which surprised me). The cadence was normal for all other minutes of this test except the left-leg unclipped. As I went into left-leg only with right unclipped, you see the same near perfect doubling of actual power. And finally, as I return to normal power, you see the two stabilize on top of each other.

    Again, the point here is to simply illustrate the relationship between left/right, and the fact that the unit is measuring torque (bending) in the left-crank arm, and thus any power exerted from the right crank arm simply isn’t captured.

    Lastly, one item of note – when the unit measures power, it takes into account data from the accelerometer. Meaning that if I just stand (without pedaling) on the left crank-arm, it won’t produce a power value, as no angular velocity was occurring. This is expected and logical."
    DCRainmaker

    http://www.dcrainmaker.com/2013/01/s...th-review.html

    http://www.dcrainmaker.com/2013/06/s...ew-update.html

    I live in the UK. Ordering from within the EU is ok but from outside the EU you start getting hit with import duty and fees, especially on high value items.

    The Power2Max power meters built after around September 2012 are all supposed to have temperature correction built in. The older ones can be sent back to Power2Max and upgraded with temperature correction for increased accuracy also.

    http://www.power2max.de/europe/en/pr...ie/service-en/

    On that NZ shopping site they have a picture of the Power2Max triple chainset.



    When compared to a normal Shimano chainset I think I can see what the problem is. Although the Power2Max MTB triple chainset uses standard 104/64 BCD chainrings the mounting holes are rotated, so that the sensor unit can fit in place. The Power2Max MTB double chainset uses 120/80 BCD chainrings but is also rotated in the same way. By rotating the mounting holes it changes the alignment of the chainrings relative to the crankarm and puts one of the chainring bolts directly behind the crankarm. This isn't a big deal with round rings, the shift ramps might not line up as intended and the pin that stops the chain jamming behind the crankarm is removed but that's all.

    Actually changing the chainrings at home still looks possible. It might require removing the Rotor crankarm from the power meter spider to get enough space though.

    If you wanted to use oval chainrings however they can be physically fittted to the chainset but the ovalisation is going to be in the wrong place relative to the crankarm, so that they don't function as intended. That's a tricky one as it probably rules out using Rotor oval Q Rings with the Power2Max.

  8. #8
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    DC Rainmaker has since gone against his initial findings on the stages & has recommended it. I've seen the stages lined up agains quarq/srm/power tap. The most inconsistent of them all was the quarq's, due to temp fluctuations & also big/little ring changes. Plus quarqs just always seem to **** the bed

    The stages data I've seen since they have updated for the power spikes & lower cadence has been really great. ProTour guys have been backdooring their sponsors to get hands on them & word on the street is they are gonna go in a big way with a team next year.

    I don't think they are perfect by any means, but for the price & accuracy they are the best choice out there. If you have a significant leg issue, can certainly understand why they wouldn't fit. But for 99% of people...
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  9. #9
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    Power2Max MTB Power Meter

    I have some mild leg problems. The left leg does a little but I'd estimate it's something like a 95% right leg / 5% left leg power split. It makes finding a suitable power meter harder than it would be normally. The pedalling graph above from DCRainmaker shows what my power output would look like with a Stages power meter. It's a shame as otherwise I probably would get one.

    I had a reply from Power2Max regarding Rotor Q rings and whether my modified left hand crank with a Power2Max power meter would affect the accuracy. It largely confirms what I suspected:

    "thanks for your interest in power2max.

    No, sorry, this is not possible. Currently the MTB version uses the electronics and plastic cover from the road versions. If we rotate the pitch circle, one of the chainrings bolts is covered from the battery compartment. So you cannot mount the chainring. We can´t say at what point it will be possible.

    Regarding your special left crank arm,
    ...
    Regarding the accuracy of the power2max it works perfectly.

    Best regards
    Your power2max Team"
    Power2Max Support

    Another possibility that I've been considering is an SRM power meter. They actually make a Shimano Deore XT SRM now, although they're twice the price of a Power2Max. That has the advantage of working straight away with my current modified Shimano left hand crank. The only issue being that it's a double chainset with 120/ 80 BCD rings so I'd be limited to a 26T inner chainring.

    http://www.srm.de/products/srm-power...himano-xt-mtb/

    .

  10. #10
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    Power2Max MTB Power Meter

    I emailed SRM and the Shimano Deore XT SRM chainset is available to buy in the EU. The SRM has a 3 year warranty, compared to 2 years for a Power2Max. According to the product page the SRM looks like it would be around 100g lighter than the Power2Max triple chainset (I don't think the SRM claimed weight includes chainrings so it may not be a full 200g lighter).

    That's great but the Shimano Deore XT SRM only comes in a 120mm/80mm BCD double chainset version. With mountain bike chainrings that means either 38/26T chainrings with an 11-36 10 speed cassette or 39/26T chainrings with an 11-36 10 speed cassette. The 80mm BCD restricts the inner chainring to a minimum of a 26 tooth chainring. Rotor make 38/26T size q rings in 120/80mm BCD so I could run oval chainrings on the SRM.

    My current setup is 44/33/23T triple chainrings with a 10 speed 12-32 cassette. The bottom gear actually works out about the same but I'd lose some top end speed and there are much bigger gaps in the gearing range using a double chainset. On the road I spend most of my time between 15 and 20mph so it's nice to have some options there with relatively close spacing jumps.

    I can't decide if it would work or not. This chart shows the gearing jumps if I switched to a double chainset.



    Extra weight and the hassle of needing to have a new crank made (Power2Max), but with the right gearing, or a lighter option that does everything I want apart from having my preferred gear ratios (SRM) ?

  11. #11
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    IMO, a double looks like it would be fine, you'll lose a couple of mph on the very low end and the top end. I'm really picky about gearing on my road bike, but I don't mind my 11-36 on the MTB for trails.

    For mountain biking on the road or dirt roads, I usually end up in a 38/13 or 38/15 for cruising, it is kind of an annoying jump, but usually the terrain is variable enough that I can make it work.

    I've had great luck with my road SRM, I change out the batteries myself, so it only costs about $20 to change. I had a reed switch go out this summer, the unit is at least 4 years old and they replaced the part under warranty at no charge.

  12. #12
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    Quote Originally Posted by sprocketjockey9 View Post
    DC Rainmaker has since gone against his initial findings on the stages & has recommended it. I've seen the stages lined up agains quarq/srm/power tap. The most inconsistent of them all was the quarq's, due to temp fluctuations & also big/little ring changes. Plus quarqs just always seem to **** the bed

    The stages data I've seen since they have updated for the power spikes & lower cadence has been really great. ProTour guys have been backdooring their sponsors to get hands on them & word on the street is they are gonna go in a big way with a team next year.

    I don't think they are perfect by any means, but for the price & accuracy they are the best choice out there..
    ^^This!

  13. #13
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    Power2Max MTB Power Meter

    I was thinking a bit more about the gearing on my ride today. I probably could get away with an MTB double chainset at a push.

    The main thing would be losing the 44x12 top gear. I don't really use top gear that much - winding it up down the hills on tarmac occasionally but that's about it, hardly ever offroad. When I do use it it comes in handy though.

    A few weeks ago I was out for a ride and caught somebody on a road bike up a climb. Over the top of the climb the road goes downhill at a gentle slope, too gentle to tuck in and freewheel but downhill enough that pedalling you can easily reach 30mph+. He came back past, dropped me and rode away down this slope, simply because I ran out of gears and couldn't pedal any faster. With a lower top gear this would be an even more frequent occurrence, especially on road club runs where everyone else has higher gearing available and a tendency to wind up the pace before the coffee stop.

    I like the close range on the middle ring too. Being able to upshift one sprocket at a time 15-14-13-12 gives a decent kick when I'm trying to accelerate whilst holding a particular cadence. It also gives a choice of gears for riding tempo on the flat.

    So long as I can keep rebuilding the fitness I'm not too worried about the bottom gear though. With my current setup I have the option of fitting a 36T rear sprocket for a 23x36T bottom gear if needed for major climbing. I use 12-32T sprockets normally for the closer range as I can get up most Cotswold climbs on 23x32T ok. I went up the 10% gradient climb out of town today without too much effort so a 26x36 bottom gear should be fine, although there isn't much of a safety margin if I'm tired or find myself on an unplanned route with monster climbs.

  14. #14
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    Power2Max MTB Power Meter

    There's a bit here about Power2Max zero offset numbers using a Garmin Edge and also the temperature compensation with Power2Max:


    "FROM POWER2MAX:

    Hi Fuji Racer,
    Thanks for your message. The "calibration" function of the Garmin is a bit of a misnomer. It establishes a manual zero by asking the power meter to zero. The result is the same as when you let the power2max do an auto-zero. The calibration of the power meter (also sometimes called the "slope") does not get affected by this.

    There is no harm in doing the Garmin calibration when it starts up, but there is also little benefit, since your power2max rezeros every time you stop pedaling for at least 2 seconds.

    I hope this helps!

    Best
    Nicolas"

    -----------------

    "FROM POWER2MAX:

    Hi,

    The absolute offset value is meaningless. It can vary depending on exactly how strongly you torqued different screws, etc. A 4 point change in the zero offset number would, if you didn't coast and there wasn't any temperature compensation, mean about a 6 watt difference. The 4 points are independent of the starting value, so it doesn't matter if someone has a value of -1000,- 800 or -400 or 0. Please also don't compare them across technologies to SRM or powertap, because each company has a different measurement approach, different units, etc, rendering zero offset comparisons meaningless.

    Our units generally have a very good temperature profile before any temperature compensation. In addition to that we have implemented the temperature compensation mechanism. Your power2max runs through a temperature chamber for several days where we repeatedly cycle it from -20C to +70C. The temperature compensation curve gets recorded like this and programmed into your unit. Each unit gets its own temperature curve. This eliminates the last possibilities of drift.

    It is very dangerous to compare the power2max to other units and take them as given. For example, on my home trainer my power at a given gear and cadence will increase by about 30 watts during a session due to increases in the temperature of the fluid and resulting increases in resistance. If I were to take the home trainer as "constant" I would think my power meter drifted.

    I hope this helps, please don't hesitate to ask any further questions you may have.

    Best
    Nicolas


    https://forums.garmin.com/showthread...e-2-8-Firmware

  15. #15
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    Power2Max MTB Power Meter

    I'm still battling with this gearing issue.

    Another option that I'm looking into is having some custom chainrings made for the Power2Max chainset. If I had some custom oval chainrings made, with the same ovalisation as the Rotor rings but rotated to match up with the Power 2Max crank spider, that would give me the gearing I want.

    This company in Australia makes custom chainrings. They look nicely done from the website and include machined shifting ramps too.

    I've sent them an email to see how much it would cost.

    http://www.fetha.com.au/index.html

    .

  16. #16
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    Power2Max MTB Power Meter

    I bought a set of donor Rotor 3D cranks with the 24mm axle. The idea being that the left hand crank from it can be modified to go with the Power2Max right hand crank. What I hadn't realised is that the Rotor 3D crank is essentially a low q factor road crank that they've then put a longer axle on.

    In order for the crank to work on a mountain bike they have the longer axle and then the gap is filled with plastic spacers either side.



    My bike uses a PF30 bottom bracket so already has plastic reducers and spacers. With all those existing plastic spacers plus the Rotor plastic spacers the whole bottom bracket is going to be "unapologetically plastic" at this rate.

    There is the Rotor 3D+ 30mm axle version but this has the problem of the axle being integrated into the left hand crank arm (the Rotor 3D 24mm axle version has the axle integrated into the right hand crank arm). It's less hassle if there's just the crank arm and no preload lock ring threads etc to deal with for modifying the left hand crank arm to fit.

    I'm remembering why I went with a Powertap for my power meter previously now. Trying to sort out a suitable chainset with modifications is never straightforward.

  17. #17
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    Power2Max MTB Power Meter

    I've made a little progress.

    Fetha have confirmed that they can make the two custom oval chainrings to fit the Power2Max crank spider, allowing me to keep my current triple chainset gearing (44T round ring and then 33 and 23T oval rings) with the powermeter. I've ordered them but due to the Christmas holiday period the rings won't be ready until mid to late January 2014. First impressions from the email correspondence that I've had are good and that the end product will be decent.

    This picture shows a custom CNC Fetha XX1 chainring with narrow wide teeth that they made to use with a 110mm BCD Quarq spider. I think I'm probably going to go for this anodising finish on my chainrings too.

    http://weightweenies.starbike.com/fo...art=45#p999411



    My donor left hand Rotor 3D crank has gone off to be welded and modified into a swing crank also. I can't quite conceptualise how the swing crank is going to work with the correct q factor as yet (due to the narrow width of the Rotor crank compared to the Shimano MTB ones that are easy to modify) but it will hopefully come together sometime before Christmas.

  18. #18
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    I'd always read that ovalized chainrings mess with the accuracy of crank spider based powermeters - thinking back to when SRM was really the only game in town. Granted it's not a huge variation (off memory something like 2-3%) but its certainly not helping anything.

    anyhow, has that changed?

  19. #19
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    Power2Max MTB Power Meter

    I've read a few things about oval chainrings and crank based power meters. O.symmetric chainrings and SRM power meters were the ones discussed most as Bradley Wiggins was using them. Apparently the more oval the chainring the more of an effect it can have on power readings, causing the crank based power meter to read high:

    Note on non-round chainrings
    ”I’ve had a handful of people ask about how any sort of oval or non-round chainring affects power measurement. Put simply, it does affect crank-based power measurement. The reason has nothing to do with any of these power meters’ quality or design, but rather a simply physical reality: Our power equation that we keep referring to assumes a constant velocity. For a crank-based system, it assumes that your pedals are turning at a perfectly steady speed throughout each complete revolution. For a wheel-based system, it assumes that your wheel is turning at a constant speed. We know that neither of these situations are very likely.

    With oval chainrings, their #1 goal is to mess with this velocity. They cause your crank velocity to change during each pedal stroke, so you spend more or less time in certain parts of that pedal stroke. For example, they may want you to spend more time – slow the crank down – during the main ‘power phase’.

    While we don’t want to dive too deep into this topic, the net effect is that you’ll get slightly inflated power numbers using an oval ring on a crank-based power meter. How much this gets inflated depends on how odd-shaped your ring is (the ‘less-round’ it is, the more your power will read high). How high are we talking? Through the course of my research, I heard anywhere from 0.5% to 4%. I did not have any non-round rings during my testing, so I can’t make a claim based on personal experience.

    Just for fun, let’s say your power meter quotes +/- 1.5% accuracy. At 200 actual watts, that means your displayed power output could be 197 to 203. If your oval chainrings adds another 1.5% on top of that, we have a net of +/- 3%. On the high end, that would tell you that you’re putting out 206 watts, when you’re actually putting out 200. If you haven’t set your zero offset in three weeks, it could drift much farther than that. Did you PR on your Strava segment, or just get bad data?"
    Greg Kopecky - Slowtwitch Power Meter 301 article

    http://www.slowtwitch.com/Tech/Power..._301_3696.html

    Rotor Q rings are a 10% oval so nowhere near as extreme a shape as the O.symmetric rings.

    Power2Max use an accelerometer to measure crank rotation and position, rather than a reed switch and cadence magnet (SRM and Quarq power meters). Power2Max claim that as a result their power meter accuracy is unaffected by using oval chainrings. They also claim that their power meter accuracy is unaffected by uneven chainring bolt torque tightness too, so that you can swap chainrings whenever you like without needing to recalibrate the power meter.

    "Hi,

    Nicolas here from power2max. First of all thanks a lot to Ray for this detailed test. We appreciate very much the time and effort you put into this.

    I would like to offer some information on a few of the key questions asked here, I hope they are helpful:

    Why you can change chain rings without recalibrating: power meters are affected by chain ring changes if what they measure is affected by “where”, i.e. at which chain ring bolt, the force is applied. We call this “rotational variance”. If you manage to eliminate rotational variance then you eliminate the influence of differently flexing chain rings or uneven chain bolt torques. We have managed to eliminate rotational variance in our power meters. How we did it is our secret sauce.

    How often we sample: We use a very high sampling rate of 50Hz, i.e. 50 measurements per second. This gives us very precise measurements and allows you to use oval chain rings without problems".
    Power2Max (Post #33 in comments)

    Post #33 in the comments to this review:
    http://www.dcrainmaker.com/2013/01/p...th-review.html

    I've used Rotor oval Q Rings for several years now. I like them because the pedalling action feels nicer to me when climbing and they appear to give better traction to the rear tyre when pedalling on loose or slippery surfaces (such as loose gravel or mud). I'll often find the rear tyre spinning up trying to ride on the round outer ring through loose gravel for example. At the same speed and conditions on the oval middle ring it's straight through with no drama or wheelspin.

    There's no speed or power improvement with the oval rings that I've experienced however. It's purely because of the feel and traction benefits that I've stuck with them.

    Spinning a big gear on the road I prefer a round ring to an oval, which is why I have a 44T round outer ring. The round outer ring also avoids the front derailleur shifting issues and placement issues that you can run into with oval chainrings.

  20. #20
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    Damn. Hopefully you had all those links handy (thanks for making me feel real lazy )!!

    agree why to use the rings, I used them on my cx bikes prior to this year - new drivetrain and they weren't in the budget.

  21. #21
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    Power2Max MTB Power Meter

    Some other links about oval rings and accuracy (see the comments in the first article. This is one of the ones about Bradley Wiggins and O.symmetric rings that I can remember reading: )

    http://cyclingtips.com.au/2012/09/os...ck-or-miracle/

    http://forum.slowtwitch.com/gforum.c...;post=4251821;

    You can't get O.symmetric MTB oval rings, only road versions, but I did see mentioned on Bikeradar today that you can actually get Ogival MTB oval chainrings, including in a narrow wide XX1 single ring version.

    http://www.ogivalring.com/epages/fe4...ateaux_VTT_XX1

    I've no idea what they're like to ride with. That much ovalisation is probably going to feel rather strange and I have visions of the chain coming off if you didn't use a chainguide.

  22. #22
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    Power2Max MTB Power Meter

    I've had confirmation that my Power2Max power meter should ship in the week beginning 6 January 2014.

    I bought it direct from Power2Max in Germany in the end, paying by bank transfer. Once you place an online order they send you a confirmation email which contains their bank payment details to send the money to the next day.

    It's actually fairly straightforward to make a direct bank transfer payment overseas via online banking. You enter the euro amount that you want to send and then the online banking displays the current exchange rate and £ GBP amount that will be deducted from your account. My bank charged £4 GBP to make the bank transfer. I copy-pasted the Power2Max bank details from the email into the online payment fields as the IBAN number is quite long. I then spent ages checking it was accurate before pressing submit.

    Here's hoping it was all correct.

  23. #23
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    Power2Max MTB Power Meter

    That's a relief. I just received an email from Power2Max confirming they received the payment.

  24. #24
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    Power2Max MTB Power Meter

    When I ordered the Power2Max power meter on Monday delivery was estimated as the week beginning 6 January 2014.

    I received a courier dispatch email today, with an estimated delivery date for early next week! That's a much faster turn around than I was expecting.

  25. #25
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    Power2Max MTB Power Meter

    The big thread of everything Power2Max on Slowtwitch for reference:

    http://forum.slowtwitch.com/gforum.c...y;so=ASC;mh=25

    My Power2Max powermeter arrived from Germany on Christmas Eve. Based on my one the claimed weights on the website are quite accurate at 918g for my complete Power2Max Rotor 3D triple chainset with 44/32/22 round BOR chainrings. It needs the battery fitting before first use.



    I received in the box - complete assembled Powermeter, manual with the slope printed on the inside cover and the spider removal tool was included. I wasn't sure if the tool would be but it was fortunately.

    What you don't see from the side on pictures is how bulky the powermeter is on the outside of the crank. Compared to a Quarq there's a lot more to it. The coloured ring sticks right out and the battery compartment is chunky too. I think my right foot should still clear it easily though.



    There's no way of removing the outer chainring without removing the crank arm from the spider. The inner rings will come off but the chainring bolt behind the crankarm is too close to remove.



    Because of the chainring orientation there's no chain catcher pin behind the crankarm. If the chain were to come off the outside of the chainring it looks like the chain could potentially jam between the crankarm and spider. I'm probably going to try and do something to prevent that before I ride it. There's only a slim chance of it happening but that's not the same as saying it can't happen.

    I haven't got a modified left hand crank yet so can't use the Powermeter until that's finished sometime in January. The measurements are a lot closer than I'd like so that could still end up as a problem.
    Last edited by WR304; 12-27-2013 at 05:41 AM.

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