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Power meter

StillGoingStillGoing Posts: 5,207
edited March 2015 in Road general
I was torn between two types of power meter, ultimately opting for the Rotor Power Lt R. The other I considered was the Power2Max. As I understood it, both are right leg measurements that use a calculation to measure the left leg power based on overall power. Is this not the case? The Rotor Power Lt-R was a lot cheaper than the P2M but if the P2M does actually measure both legs, I can understand why.
I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.

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  • rozzer32rozzer32 Posts: 3,413
    Yes P2M does measure both legs power as it measures power at the spider. However it only estimates L-R balance.

    DC Rainmaker explains all in his review.

    http://www.dcrainmaker.com/2013/01/power2max-power-meter-in-depth-review.html
    ***** Pro Tour Pundit Champion 2020, 2018, 2017 & 2011 *****
  • StillGoingStillGoing Posts: 5,207
    As much as I thought. The Rotor Power Lt R does the same thing as all do all the other single crank arm based power meters. They're all just estimates of the opposing leg power then and only things like Garmin Vector and Rotor Power (not the Lt or Lt-R versions) can give accurate readings for both legs.

    Thanks anyway. If nothing else, you helped confirm for me personally I made the right purchasing decision. P2M with Rotor 3D+ cranks is a hell of a lot more expensive.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Rotor Lt R measures power in the right crank arm, then doubles it to give an estimate of total power. (brought out to better protect the battery compartment) and gives no information on left right balance.

    Rotor Lt measure power in the left crank arm, then doubles it to give an estimate of total power and gives no information on left right balance

    Rotor Power cranks measure power in each crank arm (ie. the LT & Lt R models put together) to give true total power and true left/ right balance.

    Power2Max measure power in the spider to give true total power but an estimate of left / right balance.

    Power2Max with rotor cranks may be more expensive than Rotor Lt R, but it is giving you a true measurement of total power... Rotor Lt R is giving you an estimate of total power based upon your right leg. The new Power2max with rotor cranks is only £830 on their website... I thought the rotor lt-r was around £800... for me £30 isn't a massive difference, and if spending £800 you might of well spend the extra £30 measure true total power...
  • StillGoingStillGoing Posts: 5,207
    I got the Rotor Power Lt.-R for £700 so a big difference.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • GrillGrill Posts: 5,610
    L-R balance is one of the more useless metrics. P2M classic w/Praxis rings is an absolute steal at the moment due to the Euro being worth censored all.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • jgsijgsi Posts: 5,027
    Grill wrote:
    L-R balance is one of the more useless metrics. P2M classic w/Praxis rings is an absolute steal at the moment due to the Euro being worth censored all.

    Wait until the flatearthers read thaT!
  • GrillGrill Posts: 5,610
    jgsi wrote:
    Grill wrote:
    L-R balance is one of the more useless metrics. P2M classic w/Praxis rings is an absolute steal at the moment due to the Euro being worth censored all.

    Wait until the flatearthers read thaT!

    :mrgreen:

    Seriously though, trying to change individual morphology to meet an unproven and unnecessary exception is a fantastic way to avoid measurable gains. If ya'll's want to waste time concentrating on that magical 50:50 be my guest, I'll just be over here getting faster instead. :P
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • rozzer32rozzer32 Posts: 3,413
    philthy3 wrote:
    I got the Rotor Power Lt.-R for £700 so a big difference.

    I got a Sram rival P2M classic for £570. Thanks Greece :lol:

    Classic is a little heavier and also different battery location so makes changing rings a bit more painful. But still has the same functionality as the new type s.
    ***** Pro Tour Pundit Champion 2020, 2018, 2017 & 2011 *****
  • StillGoingStillGoing Posts: 5,207
    I'd have been restricted to the type S as I run Q rings. The bike is also a BB386 EVO so without resorting to adapters it would be FSA Gossamer as the cheapest option. I don't use the power meter for any idealogical training needs, but for health reasons, so a left or right reading with an overall balance is fine for my needs. The P2M does seem the better option though if it were for training needs.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • GrillGrill Posts: 5,610
    I run Q-Rings on the classic as do many others...

    Power meter for health reasons? Do tell...
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • StillGoingStillGoing Posts: 5,207
    Suffered a stroke late last year and with the medical treatment that followed they've discovered a hole in the heart which may explain why I never get a second breath.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • GrillGrill Posts: 5,610
    And how is a power meter going to help? In order to discover your zones you'll need to do a MAP test and it sounds like that might kill you. You'd be better off setting an alert for HR on your Garmin.

    Can't imagine a single medical professional actually advised you get a PM for such an issue...
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • StillGoingStillGoing Posts: 5,207
    I already have FTP from before the stroke. Test had been done several times. Stroke was caused by a torn artery in the neck and not as a consequence of the heart condition. The hole in the heart prevents me getting a second breath so my HR goes up rapidly and stays there. As it can be effected by external and internal factors, going by HR could mean I'm over exerting or under. Power remains constant so should be a better option and a better base to go by.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • GrillGrill Posts: 5,610
    Errr... no. I guarantee that you power is nowhere near what it was before the stroke. There's a reason FTP is constantly tested and adjusted.

    I can put out 200w at 140bpm or 170bpm. You're better off going by RPE and just keeping an eye out on your hr.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • StillGoingStillGoing Posts: 5,207
    edited February 2015
    The intention is to work with both. I've no problem with red lining as the Consultant calls it, I'm just not to do it most of the time as was the case beforehand. So periodic tests to reassess FTP aren't a problem. Yes it would be easy and cheaper to just back off and tootle around, but there is no fun in that. I at least get to try and improve my performance and at the same time ensure I'm not over exerting by relying on a HRM alone.

    Edited to add:
    I guess that means my use of a PM is not solely for health reasons as there will be some fitness goals in using it, but it is another indicator for me of the stresses being exerted and in the long term whether improvements are being made.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • stueysstueys Posts: 1,332
    Grill wrote:
    jgsi wrote:
    Grill wrote:
    L-R balance is one of the more useless metrics. P2M classic w/Praxis rings is an absolute steal at the moment due to the Euro being worth censored all.

    Wait until the flatearthers read thaT!

    :mrgreen:

    Seriously though, trying to change individual morphology to meet an unproven and unnecessary exception is a fantastic way to avoid measurable gains. If ya'll's want to waste time concentrating on that magical 50:50 be my guest, I'll just be over here getting faster instead. :P

    Absolutely spot on, I've got vector which gives me a load of interesting stats. None of which you can actually do much with. My power split is normally 49:51, but can vary very slightly on long rides as I start to tire. But so what, I've not really got any idea what I can do with that information so I've really just stopped looking. Maybe if I did a lot of one leg drills on the turbo I could add the 0.5% power gain by being perfectly balanced :D

    I do think the premium on having total measured power as opposed to one of the one side only options is worth it though, purely as it gives you a more accurate assessment of your power output and removes one potential variable from the equation. But depends how tight you are on budget, one thing that my vector has shown me is that my power balance is very consistent so Iogic suggests my power reading on a one side only meter would be very consistent. And consistency is the main thing as opposed to accuracy.
  • Brian1Brian1 Posts: 595
    Sorry to hijack this thread but I heard at one time about a 4i powermeter. Does anyone have one and it compatible with campag. I would go for a stages meter but for some reason it doesn't do a campag compatible version.
  • GrillGrill Posts: 5,610
    Brian1 wrote:
    Sorry to hijack this thread but I heard at one time about a 4i powermeter. Does anyone have one and it compatible with campag. I would go for a stages meter but for some reason it doesn't do a campag compatible version.

    1. It's not yet gone to market
    2. History dictates that first gen PM's are far more trouble than they're worth.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • StillGoingStillGoing Posts: 5,207
    Go on the 4iiii web site where there is a list of compatible crank arms for the Precision power meter. It isn't compatible with carbon cranks yet and has gone through several missed release dates. At the moment, buyers with compatible cranksets have the choice of sending their crank arm to them to have the device fitted and calibrated, or buying a crank arm with it already fitted.

    Grill,

    Tried to pm you but doesn't appear to have worked. I see you're using the Classic P2M and assume you're using a 130BCD? I ask as I understand the Classic in 110BCD isn't compatible with Q rings?
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • GrillGrill Posts: 5,610
    I have both. AFAIK you can fit Q-Rings on the compact, it's just the aero ones that need to be cut in order to fit. I'll take a look to confirm...
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • StillGoingStillGoing Posts: 5,207
    It looks as if you have to cut a section of the chain ring out with aero Q rings and a P2M Classic in 110 BCD, but the P2M Type S in 110BCD is fine.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • cswitchcswitch Posts: 261
    I'd go Power2max and thats coming from Rotor Power (the full double sided version) I had 2 of the rotor PM's. Very very accurate however the ant+ signal was so weak. Regularly they would drop out (both cadence and power) and some places round town it would always drop signal in exactly the same place for the same amount of time. They seemed very prone to interference. Also, with an Ant+ dongle on my laptop they would struggle to maintain connection unless the laptop was immediately next to the cranks which isn't much help when you want to see the screen! They're also fugly looking with the plastic bit that sticks out from the back of the crank arms, though thats not a deal breaker for me, or I wouldn't have bought them in the first place.

    Power2max on the other hand, seems to have a very strong ant+ signal. Never drops. The only negative is it seemed a little prone to drift when I was on the rollers and the room I am in changes temperature. Though having said that it seems to have levelled off in this respect (only 3 weeks use).

    I would go power2max over the double sided rotor pm, and even more so if you already have a 3D or 3D+ as you can just buy the spider - about £715 with the current euro.

    I agree 4iiii is definitely one to watch but as one other mentioned first gen PMs can be an expensive gamble so I would wait at least 6 months before considering.
  • StillGoingStillGoing Posts: 5,207
    Well after reading it all and because of issues with the Rotor Lt-R, the frame they were intended for and they don't do a similar thing to the P2M, I've took the plunge on the P2M Type S to go on my existing Rotor 3D cranks.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
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