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  1. #1
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    Power meter dilemma - what would everyone do? (UPDATE)

    Currently riding a 2010 Tarmac with a threaded BB and a SRAM 975 Quarq PM.

    Getting ready to hopefully buy a new Roubaix SL4 with a OSBB BB. I don't know what I should do.

    1. Keep current PM and purchase a Praxis Works conversion kit
    2. Sell current PM, and buy a new OSBB model.
    3. Sell current PM, and buy a PowerTap G3.

    I don't race much anymore, and I'll be getting a set of November Rail 52s carbon clinchers for my everyday wheel. I don't switch wheels, so having the PM dedicated to a rear wheel isn't ( I think ) going to be a problem

    Well, what do you guys suggest?

    UPDATE 8-23

    I've decided to get a second power meter. The new one will go on the new Roubai, and I'll keep the old one on the Tarmac. Mainly because I love training with power, and want to keep the Tarmac as my trainer/bad weather bike and still want to record workouts.

    Now my new situation is what to buy. Here are what I've boiled it down to:

    1. Buy a Quarq Red22 in BB30 - or maybe GXP. I'd like to get the PM in the native BB30 and not have to run adapters. GXP is nice because it'll fit more bikes. For me this wond be a likely issue as I'll ride this frame 2-3 years and by then, tech wil advance and I'll likey Ebay the meter and upgrade.

    2. Buy a Power2Max to mount to the Specialized cranks. I like this option too because I feel like I have more flexability with cranks - change length, switch to S-works.

    I'm assuming the meters will read within say 4-5% of each other, no? I'm just taking the accuracy of each unit and assuming the worst in each direction.

    Well, what would you guys do now? lol

    THanks!
    Last edited by petalpower; 08-23-14 at 07:20 AM. Reason: Updated

  2. #2
    Ninny globecanvas's Avatar
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    BB converter.

  3. #3
    Arrogant Roadie Punk save10's Avatar
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    i have a BB adapter on my clown-car allez for my old first gen quarq. works fine.

  4. #4
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    #1 , BB converter. Keep it simple.
    "...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson

  5. #5
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    Quote Originally Posted by petalpower View Post
    Currently riding a 2010 Tarmac with a threaded BB and a SRAM 975 Quarq PM.

    Getting ready to hopefully buy a new Roubaix SL4 with a OSBB BB. I don't know what I should do.

    1. Keep current PM and purchase a Praxis Works conversion kit
    2. Sell current PM, and buy a new OSBB model.
    3. Sell current PM, and buy a PowerTap G3.

    I don't race much anymore, and I'll be getting a set of November Rail 52s carbon clinchers for my everyday wheel. I don't switch wheels, so having the PM dedicated to a rear wheel isn't ( I think ) going to be a problem

    Well, what do you guys suggest?
    how reliable has the meter been over the last few years? if you have a good quarq unit, then use the included BB converter kit (should be included with the frameset--if not, ask the shop) to use the existing unit.

    also, if you haven't tested it (slope), now would be a good time.

    there's no material performance reason to go from a 24mm to 30mm spindle. there are some nicer cranksets out there (24mm and 30mm), so if you're inclined to spend the money you sure can do a slight upgrade (maybe a little lighter, e.g., to specialized arms), but on the bike you are unlikely to notice any of this.

    IF you open things up to new meters, then you've got options, but in this case i probably wouldn't.

  6. #6
    Senior Member shovelhd's Avatar
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    Get an SRM.

    Somebody had to say it.

  7. #7
    fuggitivo solitario echappist's Avatar
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    and you managed to beat Teton to it!

  8. #8
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    Quote Originally Posted by echappist View Post
    and you managed to beat Teton to it!
    it's not always the right answer!

    for the OP based on what he posted, not spending more money on a PM seems to be appropriate. (unless of course he has money to burn, in which case buy a PM from me. ;-))

  9. #9
    These Guys Eat Oreos Creatre's Avatar
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    I would email Quarq, pay the $400 or whatever to convert it to BB30 and also have them upgrade you to a Riken body. I wouldn't trust the numbers of a S975 personally.
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  10. #10
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    Thanks guys for the advice. it appears that the Praxis Works isn't available yet for PF30 to GXP SRAM. I ended up ordering a Wheels Mfg BB. I should've remembered to ask Quarq , and maybe ill still do that.

    Ive never had any issues with my 975 crank. its been flawless.

  11. #11
    Senior Member shovelhd's Avatar
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    Now you're doomed.

  12. #12
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    Quote Originally Posted by petalpower View Post
    Thanks guys for the advice. it appears that the Praxis Works isn't available yet for PF30 to GXP SRAM.
    See the link below, are you sure about that? I have the Praxis adapter for my Shimano crank and it's been silent for 2k miles (knock on wood.)

    BTW, the non S-Works Roubaix SL4 is OSBB which is identical BB30. The S-Works SL4 is carbon OSBB which is slightly different than PF30. Just make sure you order the right adapter from Praxis if you go that route.

    https://praxiscycles.com/product/con...ramgxp-isis-2/
    Last edited by Dunbar; 08-06-14 at 10:33 PM.

  13. #13
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    Quote Originally Posted by Dunbar View Post
    See the link below, are you sure about that? I have the Praxis adapter for my Shimano crank and it's been silent for 2k miles (knock on wood.)

    BTW, the non S-Works Roubaix SL4 is OSBB which is identical BB30. The S-Works SL4 is carbon OSBB which is slightly different than PF30. Just make sure you order the right adapter from Praxis if you go that route.

    https://praxiscycles.com/product/con...ramgxp-isis-2/
    Thanks for the info. All these BB's are confusing the heck out of me! I actually called Praxis and they said the ones for the GXP are still in development and not available.

  14. #14
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    Quote Originally Posted by petalpower View Post
    I actually called Praxis and they said the ones for the GXP are still in development and not available.
    I'm not familiar with GXP but the linked adapter can be added to your cart so I'm guessing it's in stock. Here's what the description says:


    • For SRAM GXP/ISIS2, and Oval Concepts 400/500/700series GXP cranks.
    • Designed to be a proper BB for installing SRAM GXP/ISIS2 cranks in either BB30, PF30, or Specialized’s OSBB road frames.

  15. #15
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    Quote Originally Posted by Dunbar View Post
    I'm not familiar with GXP but the linked adapter can be added to your cart so I'm guessing it's in stock. Here's what the description says:


    • For SRAM GXP/ISIS2, and Oval Concepts 400/500/700series GXP cranks.
    • Designed to be a proper BB for installing SRAM GXP/ISIS2 cranks in either BB30, PF30, or Specialized’s OSBB road frames.
    It says 73mm/MTB is for a Mountain Bike application. Am I missing something?

  16. #16
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    They make a 68mm one for road bikes.


    • 68mm Road version / 73mm MTB Version

  17. #17
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    Posted this in the OP, and figured I'd bump the thread too:

    I've decided to get a second power meter. The new one will go on the new Roubai, and I'll keep the old one on the Tarmac. Mainly because I love training with power, and want to keep the Tarmac as my trainer/bad weather bike and still want to record workouts.

    Now my new situation is what to buy. Here are what I've boiled it down to:

    1. Buy a Quarq Red22 in BB30 - or maybe GXP. I'd like to get the PM in the native BB30 and not have to run adapters. GXP is nice because it'll fit more bikes. For me this wouldn't be a likely issue as I'll ride this frame 2-3 years and by then, tech wil advance and I'll likely Ebay the meter and upgrade.

    2. Buy a Power2Max to mount to the Specialized cranks. I like this option too because I feel like I have more flexibility with cranks - change length, switch to S-works.

    I'm assuming the meters will read within say 4-5% of each other, no? I'm just taking the accuracy of each unit and assuming the worst in each direction.

    Well, what would you guys do now? lol

    THanks!
    Last edited by petalpower; 08-23-14 at 07:25 AM.

  18. #18
    Senior Member shovelhd's Avatar
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    I'd get an SRM, but of those two choices I would get the Power2Max. The Specialized crank is really sweet.

  19. #19
    fuggitivo solitario echappist's Avatar
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    Quote Originally Posted by petalpower View Post
    Posted this in the OP, and figured I'd bump the thread too:

    I've decided to get a second power meter. The new one will go on the new Roubai, and I'll keep the old one on the Tarmac. Mainly because I love training with power, and want to keep the Tarmac as my trainer/bad weather bike and still want to record workouts.

    Now my new situation is what to buy. Here are what I've boiled it down to:

    1. Buy a Quarq Red22 in BB30 - or maybe GXP. I'd like to get the PM in the native BB30 and not have to run adapters. GXP is nice because it'll fit more bikes. For me this wouldn't be a likely issue as I'll ride this frame 2-3 years and by then, tech wil advance and I'll likely Ebay the meter and upgrade.

    2. Buy a Power2Max to mount to the Specialized cranks. I like this option too because I feel like I have more flexibility with cranks - change length, switch to S-works.

    I'm assuming the meters will read within say 4-5% of each other, no? I'm just taking the accuracy of each unit and assuming the worst in each direction.

    Well, what would you guys do now? lol

    THanks!
    difference of 4-5% is a lot. At 300W, that's 15W, or gains you'd work a season or two to get.

    As such, the meters should be made by the same company, and you should test out the slopes to make sure they are consistent.

    I have 2 SRM, one purchased last November and the other recently serviced in June. I somehow thought the recently serviced unit was reading quite high due to high average power from races, and did a static torque test to make sure things are right. The unit purchased in November had a slope that was spot on, and the recently serviced unit was 2.2% high, but this would not explain the high power expended in races. Nonetheless, i needed to do my workouts with different expectations, knowing that if i were a few watts shy of what i had been doing, it doesn't mean i'm losing power.

  20. #20
    Ninny globecanvas's Avatar
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    Doesn't directly answer your latest question, but just to throw info into the pot, I have been running a GXP crank in a BB30 Crux for a couple years using the $30 Wheels Mfg adapters, with no issues. I did this so I could use a PM I already had.

  21. #21
    Powered by Borscht ovoleg's Avatar
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    Quote Originally Posted by Creatre View Post
    I would email Quarq, pay the $400 or whatever to convert it to BB30 and also have them upgrade you to a Riken body. I wouldn't trust the numbers of a S975 personally.
    this.
    -Cat-3-o-meter: TBD :/

  22. #22
    Powered by Borscht ovoleg's Avatar
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    Quote Originally Posted by globecanvas View Post
    Doesn't directly answer your latest question, but just to throw info into the pot, I have been running a GXP crank in a BB30 Crux for a couple years using the $30 Wheels Mfg adapters, with no issues. I did this so I could use a PM I already had.
    been running GXP with the $30 adapter for about a year now, before that ran the GXP on my other bike without issues.

    +1 for Quarq Riken
    -Cat-3-o-meter: TBD :/

  23. #23
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    Quote Originally Posted by Creatre View Post
    I would email Quarq, pay the $400 or whatever to convert it to BB30 and also have them upgrade you to a Riken body. I wouldn't trust the numbers of a S975 personally.
    Faced with this exact dilemma I did this and bought a Wahoo Kickr for training with power, which works out about the same price as a new power meter.

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