Results 1 to 25 of 25
  1. #1
    RoadBikeReview Member
    Reputation:
    Join Date
    Apr 2004
    Posts
    312

    Which Power Meter: Power Tap, SRM, or Ergomo?

    I'm toying with the idea of getting a power meter, and I've narrowed it down to these three. Pros and cons of each as I see it:

    Power Tap

    Pros: Wireless available, easy to install (once the wheel is built), cheapest of the three (I think).

    Cons: Power functions work if you use multiple wheelsets (this is actually a pro if I want to strip down weight for race day). Does the wireless transmission make this unit any heavier than the other two?

    SRM

    Pros: Everything I've heard is that this is the best and most accurate of the three. Rechargable head unit so batteries shouldn't be an issue. Can use with any wheelset.

    Cons: Cost. Must use their (heavier) crankset or pay a premium for the SRM compatible carbon FSA. Wired.

    Ergomo

    Pros: About half the price of an SRM. Rechargable(?). Use with any wheelset. Will work with my carbon Chorus cranks. Works with all wheels.

    Cons: Wired unit. Relatively new product - is it durable and reliable? Any quaility control issues?

    Did I miss anything? Anyone know how weight compares amoung the three? Any other insight?

    If I take the plunge, I'm probably leaning towards the Ergomo. I don't think the SRM is really a realistic option given the cost, but I think I should keep it on the table for now just so I know what (if anything) I would be giving up in not going that way.

    Thanks for the input!!

  2. #2
    DraftMaster
    Reputation:
    Join Date
    Jul 2006
    Posts
    213

    You're missing one

    The Polar CS600. It's a beautifully designed unit. It's lighter and cheaper than any of the others. It's wireless to the head unit which is smaller and more aero than any of the others.

    Before you buy the Ergomo, read some of the user feedback (nightmares) here:

    http://www.excelsports.com/new.asp?p...ajor=3&minor=2

  3. #3
    What? Me worry?
    Reputation: StillRiding's Avatar
    Join Date
    Sep 2006
    Posts
    817
    There are four reasonable choices for power meters, shown below with street price:

    Polar CS600 - $550
    Ergomo Pro - $1450 plus crankset if required
    PT in many configurations - $1000 to $2000 depending on hub and wheel choice
    SRM in many versions - $2200 to $3500

    All of these devices will give workable power information. Your choice should come down to your budget, the features you want and the constraints you are willing to accept.

    The CS600 is an ugly installation and power info may need to be edited to smooth out spikes. The power unit battery is a disposable with short life. Memory capacity is short compared to other meters. It's the best bang for the buck and does have altitude and temperature information and comes with good software. Swapping bike to bike is relatively easy.

    The Ergomo Pro requires careful installation and frequent checking of offset. It has altitude and temperature info, customizable user screens and an excellent interval mode. It can't be used with an external bearing BB and swapping bike to bike is very difficult. Software is excellent.

    The PT units are by far the most popular, but you'll need to buy a hub for each wheel you want to use, and you won't be using it with your Ksyriums. Swapping bike to bike is as easy as changing wheels. Wireless versions have been reported as prone to dropouts and some hubs have had problems in the rain. No altitude or temp info, software is second rate, but customer support is excellent.

    SRM (Pro) is touted as the most accurate and reliable, and for the price it should be. Swapping bike to bike is not too difficult. As nice as SRM might be, the price of this unit puts it out of the range of most people except for coaches and serious amateurs or pros...or people who just have more money than brains.

  4. #4
    Impulse Athletic Coaching
    Reputation: iliveonnitro's Avatar
    Join Date
    Feb 2006
    Posts
    5,878
    Buy the best one you can afford. The SRM is probably the best bet.

    Ergomo only measures power on the left crank, and doubles it to get your power number. Some say it is extremely accurate, while i've heard others having a problem due to muscle imbalances, etc.

    PT is a great choice, although most people will have to send it in for repairs (at least the 06 and previous models). Saris has excellent customer support, though. Its probably the best cost to performance model.

    Polar is, more often than not, inaccurate. I wouldn't recommend it if you are serious about training with power. It might be OK for a fun toy at most.

  5. #5
    DraftMaster
    Reputation:
    Join Date
    Jul 2006
    Posts
    213
    Quote Originally Posted by iliveonnitro
    Polar is, more often than not, inaccurate. I wouldn't recommend it if you are serious about training with power. It might be OK for a fun toy at most.
    Whoa, that's harsh!

    Polar recieved some bad reviews based on earlier models such as the 725x.

    This new model stacks up well against the others. I'll admit, as an earlier poster said, the install is a little clunky. But it works. I've had zero problems with this unit for several thousand miles. The batteries have not needed replacement. The software reveals battery charge remaining in the head unit, the speed sensor, and the head unit. It's much more than than a "fun toy." This unit was used successfully by several Tour riders this year.

    Here's a review of Polar vs other systems:

    http://www.biketechreview.com/archive/pm_review.htm

    The author shows that Polar compares very favorably with the other units at near half the price (and he's using the older 725-series.)

    Don't be that quick to judge. Do your homework.

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Aug 2006
    Posts
    124
    polar doesn't work on a trainer(725) estimates power, doesn't count zeros(725). Can be difficult to set up. Do you really need temp?
    Iv'e been using a PT for a few years now and yes there have been some issues.
    But for the most part it's been very reliable. Customer service is GREAT.
    SRM great unit expensive does have it's own drawbacks. Ergomo also very good but expensive to repair/replace bearings.

  7. #7
    RoadBikeReview Member
    Reputation:
    Join Date
    Dec 2004
    Posts
    525
    ive heard bad things about the ergomo, and the polar, and ibike.

    Go with either the powertap or srm.

    the srm is a much better set up. with powertap you have to have a sensor on the seatstay or chainstay.

    SRM wired is a plus, not a con. There are lots of problems with wireless computers. they are just not as reliable. (you can argue with me, but you cant beat personal experience).

    If you can save up or get the SRM. they are great, reliable, and the most acurate. if you have a problem you can get it fixed. they are like king headsets, you would bring it along with you when you change bikes. get the srm

  8. #8
    DraftMaster
    Reputation:
    Join Date
    Jul 2006
    Posts
    213

    Defending Polar

    Quote Originally Posted by mytorelli
    ive heard bad things about the ..., and the polar, and ....
    Okay, once again I will take up the cause of defending the Polar CS600.

    It is true that the previous iteration of Polar products with Power Meters, notably the 725 series, had serious reliability and installation issues and basically were POS products.

    This new version has addressed those issues and it actually WORKS, I tell you!

    Here are reviews from RBR:
    http://www.roadbikereview.com/cat/tr...4_6207crx.aspx

    Please note that the negative reviews ALL refer to the 725 series.

    Here are reviews on Amazon:
    http://www.amazon.com/Polar-CS600-Cy.../dp/B000QDYB92

    And from Pez:
    http://www.pezcyclingnews.com/?pg=fullstory&id=4884

    Try to keep an open mind here, folks. Polar has listened to consumer complaints and vastly improved their product. And, I'm not sponsored by them... yet.

  9. #9
    RoadBikeReview Member
    Reputation:
    Join Date
    Dec 2005
    Posts
    273
    Anyone have a chance to play with the iBike?

  10. #10
    Not Banned
    Reputation: atpjunkie's Avatar
    Join Date
    Mar 2002
    Posts
    42,273

    not an endorsement

    but I saw the ergomo and it had 2 sensors on the BB spidle fairly centrally located so that 'measures left crank arm' methinks is urban legend
    one nation, under surveillance with liberty and justice for few

    still not figgering on biggering

  11. #11
    All I wanted was a Pepsi!
    Reputation: lemonlime's Avatar
    Join Date
    Sep 2003
    Posts
    5,337
    I bought the powertap wireless model and so far it has been awesome. Initially I had some problems with the heartrate or cadence sensor measuring waaaayyyy high, but it seems to have worked itself out (or the crossed chicken bones I waved over it had some affect).

    I've heard bad stuff about it's weatherproofing, however, so I don't take that bike if it looks like rain coming but that's about all I can think of for cons at this point. Of course, I've only had it since late April...
    "If you have the guts to be yourself, other people'll pay your price." - Rabbit Angstrom

  12. #12
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    Quote Originally Posted by atpjunkie
    but I saw the ergomo and it had 2 sensors on the BB spidle fairly centrally located so that 'measures left crank arm' methinks is urban legend
    Me thinks you thinks wrong. The BB never sees the torque from the right arm - straight to the chain rings. - TF
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  13. #13
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    First get the book, read everything you can and figure out what you are going to do with it. Once you know that, you can get the cheapest one that does what you want. If you just like toys, then get the most expensive one you can afford. - TF
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  14. #14
    Not Banned
    Reputation: atpjunkie's Avatar
    Join Date
    Mar 2002
    Posts
    42,273

    so you are saying a BB

    doesn't register crank force on one arm?
    one nation, under surveillance with liberty and justice for few

    still not figgering on biggering

  15. #15
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    Quote Originally Posted by atpjunkie
    doesn't register crank force on one arm?
    Correct. The BB transfers the torque from the left crankarm. The right one is connected directly to the spider/chainrings. The Ergomo measures the left side and multiplies by two. - TF
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  16. #16
    Not Banned
    Reputation: atpjunkie's Avatar
    Join Date
    Mar 2002
    Posts
    42,273

    thx

    Quote Originally Posted by TurboTurtle
    Correct. The BB transfers the torque from the left crankarm. The right one is connected directly to the spider/chainrings. The Ergomo measures the left side and multiplies by two. - TF
    but I'm thinking that force exerted by the right leg still has to register no? it all goes to the chain?

    does the SRM work better because it is attached to the crank? I'm seeing your point and appreciate the help
    one nation, under surveillance with liberty and justice for few

    still not figgering on biggering

  17. #17
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    Quote Originally Posted by atpjunkie
    but I'm thinking that force exerted by the right leg still has to register no? it all goes to the chain?

    does the SRM work better because it is attached to the crank? I'm seeing your point and appreciate the help
    The right side force goes directly from the foot>pedal>crankarm>spider>chainring>chain. Only the left side tries to 'twist' the BB which is what the Ergomo measures.

    The SRM configuration is different, but not necessarily better.

    They all (SRM, Ergomo, PT, Polar, iBike - in $ order), in theory, have enough information to calculate power within the accuracy required. There is nothing magic about the technique any of them use and none measures power directly. They all have strengths and weaknesses. Most of the weaknesses are in implementation, not technique.

    The Ergomo measures the torque or twist in the BB from the left side and doubles this value. Most agree that the right/left difference (unless you have an actual medical problem) is insignificant, but it does exist. Also it seems that the left/right ratio changes with fatigue. Implementation: Some report them to be extremely picky in installation and quite fragile. Others use them in 24hr endurance MTB racing. I have no experience.

    The SRM measures torque or twist of the spider. The technique is sound and most of the problems seem to be in the sensor/electronics. For me, it is a matter of price. My most expensive bike, complete with a Power Tap, costs less than an SRM. It seems that frequent calibration by the user (measuring the torque with weights attached to the pedal) is required to maintain the accuracy stated.

    Someone above asked about the iBike. It measures the forces opposing the bike/rider such as acceleration, air speed, etc. The sum of these forces has to be equal to the force being exerted to overcome them. Force and velocity gives power. Though some call it an 'estimator' rather than a meter, this technique is just as valid as any of the others. IMO, however, the affordable technology just does not exist yet to implement this technique to the accuracy/precision that I require.

    A brief mention of the Polar. It measures the frequency of the chain vibration which is proportional to the force being applied to the chain. Force with the chain velocity (measured at the rear D) gives power. Reports vary widely and I have never even seem one so will not comment. I have not investigated further because the recording time
    (only 4 hours at 1 sec) is a deal-breaker for me.

    My choice is the Power Tap. You can get a new SL with Open Pro for <$900 shipped on eBay or get a used Pro/Open Pro, have Saris rebuild it and have what I need for <$600. At this price I can have multiple wheel sets and switch them between my bikes and my wife's by need. They also seem to be either accurate or broke which matches well with my calibration frequency - I don't (some call this 'head in the sand' calibration). I also have no need for elevation, temperature, phase of moon, etc.

    I gotten a little windy here, but my point is that you need to decide what your requirements are and find the one that matches them the best. Power meters are not yet at the level of HR monitors in that you can just buy any one and it will give you an accurate heart rate (though what is inferred from the HR is often garbage).

    Good luck,
    TF
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  18. #18
    DraftMaster
    Reputation:
    Join Date
    Jul 2006
    Posts
    213
    Excellent analysis TurboTurtle. One of the better posts on this thread. I have to agree about the Polar recoding capacity. My CS600 actually has less capacity than you stated. At 1 sec. intervals it claims only 2:50 in capacity. At 5 sec. it's over 14 hours. They need to increase memory capacity and add a 2 or 3 sec. option. In practice, however the unit does continue to record just fine well beyond it's stated capacity. Not sure what's up with that, but I've had it set on 1 sec. and a two-hour ride which became a five-hour ride recorded just fine. All data continued to record, with no apparent gaps. It beeps once to say you're running out of memory, but like most warnings, I ignore it.

  19. #19
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    Quote Originally Posted by rcordray
    Excellent analysis TurboTurtle. One of the better posts on this thread. I have to agree about the Polar recoding capacity. My CS600 actually has less capacity than you stated. At 1 sec. intervals it claims only 2:50 in capacity. At 5 sec. it's over 14 hours. They need to increase memory capacity and add a 2 or 3 sec. option. In practice, however the unit does continue to record just fine well beyond it's stated capacity. Not sure what's up with that, but I've had it set on 1 sec. and a two-hour ride which became a five-hour ride recorded just fine. All data continued to record, with no apparent gaps. It beeps once to say you're running out of memory, but like most warnings, I ignore it.
    I've read someplace (it may have been speculation???) that it automatically goes to longer recording times. I don't remember if it goes back and chages all the data or just stats recording less as it gets near full. - TF

    EDIT - I believe that it is in this thread someplace. http://www.cyclingforums.com/t391098.html You may have to register to see it???

    EDIT2 - Nope, this one: http://www.cyclingforums.com/t-388692-15-2.html
    From the manual:
    "Recording Rate

    Select Settings > Features > Rec.rate > 1 / 5 / 15 / 60 sec

    The cycling computer can store your heart rate, speed, cadence, power and altitude in 1, 5, 15 or 60 second intervals. A longer interval gives you more recording time, while a shorter interval allows you to record more heart and other data. This enables accurate data analysis using the Polar ProTrainer 5 software.

    A shorter recording rate consumes the memory of the cycling computer more rapidly. The remaining recording time is displayed on the lower row when setting the rate. Default recording rate is 5 seconds.

    When less than 30 minutes of maximum recording time is left, the recording rate changes automatically to longer recording time (1s > 5s > 15s > 60s). This will maximize recoding time to record exercise data. When the session ends, the current recording rate will be used in the next training session.

    The following table shows the maximum recording times for each recording rate. The maximum recording time can be shorter, if you record a large number of short exercises.

    Recording rate will change when less than 30 minutes of recording time is left. Memory low is displayed 60..."

    Note that you have to manually change it back to your original interval.

    TF
    Last edited by TurboTurtle; 08-10-2007 at 08:35 AM.
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  20. #20
    DraftMaster
    Reputation:
    Join Date
    Jul 2006
    Posts
    213

    Polar CS600 Meory Capacity

    Thank you, TurboTurtle! I did not know how the Polar continued to record after the allotted time. Actually, that's a remarkably clever feature written into the software. I had orinally assumed that I would just lose the ensuing data after memory ran out.

  21. #21
    NeoRetroGrouch
    Reputation: TurboTurtle's Avatar
    Join Date
    Feb 2004
    Posts
    6,496
    Quote Originally Posted by rcordray
    Thank you, TurboTurtle! I did not know how the Polar continued to record after the allotted time. Actually, that's a remarkably clever feature written into the software. I had orinally assumed that I would just lose the ensuing data after memory ran out.
    Actually for many of us it is just a waste of the remaining time since a 5 sec rate (especially since it is not an average of the 5 seconds) has little value. - TF
    "Don't those guys know they're old?!!"
    Me, off the back, at my first 50+ road race.

  22. #22
    RoadBikeReview Member
    Reputation: slowdave's Avatar
    Join Date
    Nov 2005
    Posts
    647
    Ride (aussie bike mag) has done a review in the past three issues maybe four, it rates software, accuracy etc. Ride has a box on the side of the cycling news have a look, for me i think the power tap is the best value for money very accurate relative price, good features

  23. #23
    What? Me worry?
    Reputation: StillRiding's Avatar
    Join Date
    Sep 2006
    Posts
    817
    Quote Originally Posted by TurboTurtle
    Actually for many of us it is just a waste of the remaining time since a 5 sec rate (especially since it is not an average of the 5 seconds) has little value. - TF
    How is data handled by the Polar CS600 when recording at 5 second intervals? Could you provide a reference that describes the process?

    In my observation, after actually using a Polar CS600, for any ride longer than the approximate 2:20 that I can record at 1 second intervals, there's not much going on that I really need to record more frequently than once every 5 seconds. After 2+ hrs, I'm not typically working on speed or doing any short duration, high intensity intervals.

    I would also like to stress that the altitude function is VERY helpful when reconstructing a ride.

    On the other hand, again based on real experience, the power battery holder and connections on the Polar CS600 are really second rate. The life of the disposable power battery is poor, the whole setup is prone to loose connections, it's ugly, and it's ugly. I meant to say ugly twice.

    Finally, the CS600 does provide accurate and consistent power information when it is properly installed, the only exception being power spikes when shifting is less than smooth. If you can deal with the quirks, the CS600 is by far the best buy in power meters.

    P.S. It is not necessary to manually change back to the pre-selected recording rate if the unit goes to the next higher rate. Once data is downloaded and the memory cleared, the unit will automatically go back to the pre-selected recording rate.
    Last edited by StillRiding; 08-13-2007 at 04:55 AM.

  24. #24
    RoadBikeReview Member
    Reputation:
    Join Date
    Feb 2008
    Posts
    42

    Any Up Date Using The Cs600x?

    Doe anybody has a experience using the cs600x (wind) with the polar power sensor?

  25. #25
    RoadBikeReview Member
    Reputation:
    Join Date
    Nov 2008
    Posts
    1,058
    Are any of these compatible with the Garmin 705?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

EUROBIKE

Hot Deals

Latest RoadBike Articles


Latest Videos

RoadbikeReview on Facebook