New to power training

Discussion in 'Power Training' started by danbh, Oct 31, 2011.

  1. danbh

    danbh New Member

    Oct 31, 2011
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    Im thinking of incorporating power into my training and have been trying to sum up which path to take. SRM, Powertap or one of the new pedal based systems. I am edging towards the powertap route as I want to use it on multiple bikes with the least amount of fuss, but would like others opinions on which route would be the best to take.

  2. Koolstof

    Koolstof New Member

    Oct 19, 2011
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    I'm sure you've probably seen this already, but the following thread gives something of an overview of whats out there.

    I posted it on that thread too, but we've just taken stock of our 2012 PowerTaps, so I am a little biased in that favour, but all said and done, I think it is an impressive and flexible system.

    I'm hoping the latest Powertap releases will have addressed bearing challenges sometimes associated with PowerTap hubs... certainly the theory sounds good!

    I wrote an (admittedly) salesy article last week on the new PowerTaps which you can read here.

    As for your needs, that depends to a degree on budgets and intended purpose. Do you want to use it racing, or training, or both. Will you want to transmit the system from one bike to another, or will one bike suffice?

    The benefits of PowerTap are that they can be transferred from one bike to another, so you can easily have power on all road based bikes. The negatives are that you are only a puncture away from not having power measurement (annoying in races), and that there have been some challenges around the bearing life, although from what I here from UK distributors, that may have been addressed now.

    SRM are the original system and still a favourite of the pro's. The associated price tag makes them less popular for the privateer.

    The pedal systems from Polar and Garmin are a little new to comment on, but if you like Look pedals and feel that knowing individual legs outputs could be useful, then they could be worth a look.
  3. daveryanwyoming

    daveryanwyoming Well-Known Member

    Oct 3, 2006
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    Nothing wrong with PowerTap systems, but SRM and Quarg crank based systems are also very easy to swap from bike to bike. It takes less than five minutes to swap a set of SRM Dura Ace cranks from one bike to another and you can use it with any set of wheels. Just keep bottom brackets and any necessary wiring harnesses (only for the wired SRM units) mounted on both bikes and the crank swap is trivial.

    I used PT sytems for several years and they're great but I ended up accumulating several different PT wheelsets to cover training, road racing and TT situations and at that point it was simpler and less expensive to sell the set and go with swappable SRM cranks and get a real disc wheel instead of a covered PT wheel or very expensive PT equipped disc for my TT bike.

    The basic questions are whether you race and if so whether you'll run the same wheels on race day, buy a set of dedicated PT race wheels or just ignore power data from races which a lot of folks do, but it's a shame as race data can be very useful for identifying strengths and weaknesses and opportunities to improve. If you care about data accuracy I'd strongly suggest a PT, SRM or Quarg system that allows you to hang known weights off the cranks to measure and validate strain guage accuracy (which translates to torque and hence power accuracy). The pedal based systems may be great but will likely be hard to verify their accuracy in the field (due to their accelerometer based designs instead of more conventional strain gauges) which can be important when the numbers don't seem to add up or you try to do things like aerodynamic testing and want accurate power numbers. I started with an Ergomo system and that lack of field accuracy testing ended up being the deal breaker as the unit would report some really unusual numbers at times and there was no way to know whether I was having an unusually good or bad day or whether the unit was just out to lunch. A couple of years with field verifiable PT and then SRM units made me realize it was the latter.

    A lot of good systems out there, but it really depends on your needs and your budget.

    Good luck,
  4. lanierb

    lanierb New Member

    Aug 12, 2004
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    All of them work well. I can't think of anyone who started with a crank-based PM (SRM/Quarq) and then moved to the PT, but I know lots of people who went the other way (including me). The reason is as Dave says: if you do any racing you will want to be able to use different wheels on your bike, and that gets expensive and difficult with the PT. Also, with the PT every time you think about buying new wheels it becomes an expensive and complicated undertaking (that may or may not involve rebuilding both your old wheel and your new wheel around a different hub, etc).

    Also, if you have two bikes both set up for the same crank then swapping cranks can easily be done in less than a minute. Here's the proof: and this was done in "one take" without rushing, and he even used a torque wrench to finish it off (not always necessary). Now obviously he's done it before and it will take a bit more than one minute your first time, but after you've done it 5 times it's really quick and easy. Is it harder than changing a wheel? Yes, but not as much as you think.

    So bottom line is if this is for training/fun only and you're not the type to lust after fast wheels, then by all means get the PT. If you plan on doing some racing and you like the idea of using fast wheels sometimes, then you're better off with the Quarq/SRM -- and probably the Quarq since it's way cheaper, works just as well, and battery changes are much simpler (Quarq uses a large button battery that can be bought at Walmart and changed in 30 seconds, SRM uses a much more expensive and harder to find battery, and nominally you're supposed to send it back to SRM for a battery change, though many people have figured out how to do it themselves).