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Power at the crankset? Preferences

ghankinsghankins
in General Training Discussions

So I'm ready to drink the Kool Aid for power meters and have decided to do crank based because I don't want to deal with switching wheels and all the other fun games with power tap, also momma wont let me buy another set of wheels to sit around.  

So I have been looking into SRM wired and wireless and quarq used because of the price points but I'm nervous about biting into one or the other because I don't want to spend a ton of money and then have it not fit.  What I am meaning by this every bike now a days has their own bottom bracket BB30 and so on, there seems to be a million different ways to go.

My bike is a 2012 Felt DA1 which is BB30 but I am using an adapter that reduces to run the 130 BCD size for my Dura Ace 7900 (seems to work great, it pressed in and I haven't had a problem with it yet so I say leave it alone unless I have to jump up to BB30). When looking at a lot of the power meters they say 130 BCD but I have cross referenced a few quarqs and they say they wont work with BB30 and the adapters.  So confused now.  So does any one run Felts BB30 with crank based power on EN, would love to hear their thoughts?

Also can a used power meter be trusted?  I have talked on and off with a few people and  I'm really interested in a SRM FSA K Force Carbon wireless but it was supposedly made in 2008 but not used till 2011 then sent in for calibration in 2012 and hasn't been used since.  Is that a bad buy considering the power meter was made nearly 5 years ago?

The other one I'm considering is also a SRM FSA Gossamer which is the cheaper side of the SRM but doesn't come with a head unit (my garmin can take care of that though) this one is a year old and has all paperwork and SRM recently changed the battery and calibrated it.  

I would also consider Quarqs but haven't really had the chance to research them much and they were the ones with compatibility issues.  For some reason some of them wont fit because they would hit the frame or need to be modified.

Help so confused, thanks in advance for your input.

Thanks Greg

Comments

  • ghankinsghankins
    Also forgot to mention, I run Dura Ace Di2 components with a Dura Ace cassette so does Sram and Dura Ace mix and match if I went with Sram Quarq?
  • John WithrowJohn Withrow

    Hey Greg--   SRAM and Shimano work interchangeably just fine.  I'm currently using a wireless SRAM S950 SRM with a GXP bottom bracket on my P5 (which comes with a BBRight bottom bracket) using 7900 Dura Ace Di2.  It works flawlessly after the adapter.  My Road bike has a BB30 Bottom Bracket and I simply had an adapter installed to convert it to GXP (did the same on my P3) so now I can swap my SRM crankset between bikes in a matter of seconds with no issues whatsoever.  I went with a GXP crankset because there's and adapter for just about any bottom bracket in the world to take GXP crankset, but not the same for BB30.  In other words putting a GXP crank on a BB30 bottom bracket is simple, but putting a BB30 crank onto a GXP bottom bracket is almost impossible.   I'm pretty sure an adapter to take an FSA crank is also pretty simple and straight forward.

    The 130 BCD you mentioned simply means that you are currently using a Standard Crankset (53/39 teeth).  BCD stands for Bolt Center Diameter and simply means that it is made for bigger chainrings.  110 BCD is the standard used for Compact Cranksets (50/34).  Most on EN will push you towards getting a Compact instead of a Standard which you can read about here.

    Regardless of what Bottom Bracket you have or what brand you choose, you will need to decide if you want a Standard or Compact. If you are buying an expensive powermeter crankset, you will also want to get exactly the right crank length.  Many have been going the route of shorter cranks.  I am 6'-1" with a ~32" inseam and I am very happily riding 170mm cranks.  How tall are you?  I can point you toward some resources if you have questions on this.

    I don't know what price range you are looking at, but you should send BicycleDoctor@att.net an email and ask for pricing on the Quarqs. About a month ago, they were offering the RIKEN for $1,299.90 (+$50 for BB30) and the Elsa for $1,599.90 (+$50 for BB30). I just bought an Edge 510 from them and I have 2 friends who recently bought the RIKENs from them (and I think Dawn Cass from EN also just bought one from them). For my money, I'd get the RIKEN and save the $300... $300 seems like a lot for 88 grams and L/R balance... Unless you happen to need a really short crank and then you would need the ELSA since the RIKEN only goes down to 170mm.   

    I have also seen plenty of Quarq's trade on eBay for $950-1,200.  Here's one that ends in 2 hrs that has a 52/36 (which is kind of a nice mix in between a standard and a compact).  I wouldn't be surprised if this trades below $1,000...   http://www.ebay.com/itm/Quarq-Sram-S975-Power-Meter-/181147228730?pt=US_Cranksets&hash=item2a2d375a3a

    As far as a head unit goes, I've only ever used mine with my Garmin...

  • ghankinsghankins

    John, 

    Thanks a ton.  As for crank length I'm 5'-9" to 5'-10" depending on what day of the week it is image. I haven't really thought too much about standard or compact but was starting to lean toward compact because I tend to be large ring rider and I am trying to break myself of that because I know it will take me out in the long race.  I'm pretty strong on hills and tend to push myself in large ring, so losing a percent or two in the gearing of compact won't kill me because I will probably make it up from saving on the fatigue.

    As for adapters my bike currently is running a FSA's ceramic adapter to reduce down to Shimano so I will probably just order the standard crank and will look into quarqs a little more but leaning toward SRM for some odd reason.  There is a few on flea bay that I have been talking to sellers about.  I will also email BicycleDoctor@att.net for pricing on a setup.

     

    Thanks once again.

  • CarlCarl
    John-
    I am also in a dilemma of Quarq vs 808 Firecrest with g3 power meter. Now I know a fair amount about the PM's but honestly really dumb when talking Quarqs or crank based power.

    Im also in need of a new back race wheel and I am not sure the wife would go for a Quarq then new back wheel. I read what you wrote above and opened by eyes to bottom bracket stuff and the 110, etc. I have been training with the 53/39 and raced two of the three IM's last year with it.

    What would you truly recommend????? Thanks
  • John WithrowJohn Withrow
    My personal opinion is that you'll get more bang for your buck out of the Quarq. I've heard of some trading for ~$900 recently. A disc cover on a training wheel is almost exactly the same from an aero perspective as a disc cover on a rear FC808. And with the Quarq, you'll have a ton more flexibility if you want to rent wheels for a different race or you can piece them together over time. I think where you ride it's pretty flat, but you'd still be fine with the compact and an 11-xx cassette. With IMMOO as an A-Race, you'll be happy you have a compact on the hills with an 11-27 or 11-28. I know you're W/Kg is pretty high, but not so high that a compact will be an impediment on the flats for a long time. You can probably almost get a used Quarq AND a front FC808 for about the same price as a rear FC808 with a G3. With the Quarq, you will also be training and racing with the same Powermeter and won't need to retest with your race wheels to make sure they match the calibration.

    Don't get me wrong, a FC808 set with a G3 is an awesome wheel. But I just think that given how much the Quarq's have come down in price over the last 1.5 yrs that the value proposition has changed. It used to be you were talking $1,800 minimum for crank based power and that just simply isn't the case anymore. So for my money I'd go (compact) crank based and front race wheel. Or you can buy the crank and rent a set or race wheels for your A race if you want and still be way ahead on total price. Hell, you could rent a set of 808's for your next 3 yrs worth of Ironmans and still probably be farther ahead. And with this approach, you could rent FC404's instead for Cozumel if you want to minimize the effect of the crosswinds.
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