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School me on BCD differences
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I am looking to get into power and can potentially get a Quarq S-works power meter for a good deal, but it is a 130BCD. I know this power meter requires me to upgrade to the Specialized carbon cranks, which I am ok with. My question is to confirm all of the above mentioned will work, but will require a new chain ring that matches this new BCD?

Any suggestions for a 52/36 chainring in 130BCD?

Current set up is as follows:

Shiv Elite 11 speed
Crankset TURN Zayante by Praxis Works, BB30, 52/36, 170mm crank arms
110BCD

Other option would be a Powertap chainring if Quarq does not work out.

Thanks.
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Re: School me on BCD differences [rbrous9] [ In reply to ]
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36t rings are too small for 130bcd. Smallest commonly available size is 39

That means to get the same low gear you'll need a rear cog that's 2 teeth bigger, eg a 11-28 instead of 11-26

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Re: School me on BCD differences [JasoninHalifax] [ In reply to ]
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I am already running an 11/28 cog, so that will work with a 53/39 chain ring?
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Re: School me on BCD differences [rbrous9] [ In reply to ]
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If you don't use your lowest gear now it will work
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Re: School me on BCD differences [rbrous9] [ In reply to ]
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Find a gear chart online. Try Sheldon Brown's site.

Don't get the 130bcd if you like your current 36x28. Keep searching for a 110 BCD power meter. Sure, you could get an 11x32 cassette to go with the 39x53, but now you've got more gaps in your cassette and you're going to have to either replace your rear derailleur or at least money with it to run a gear combo that is out of spec.

Kevin

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Re: School me on BCD differences [rbrous9] [ In reply to ]
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rbrous9 wrote:
I am already running an 11/28 cog, so that will work with a 53/39 chain ring?

It could be fine. The limiting factor will be chain length, but you're only going from a max of 52/28 to now 53/28. If the chain was cut a little long, it will likely work.

You'll know pretty quickly once you put the crank on. Go slowly down the gears and make sure the rear derailleur pulley isn't stretched to its limits as you shift to the 53/28t combination
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Re: School me on BCD differences [rbrous9] [ In reply to ]
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rbrous9 wrote:
I am already running an 11/28 cog, so that will work with a 53/39 chain ring?

following on what nslckevin wrote, the cassette sizes are independent of the chainring sizes. Any cassette will "work" with any chainring combo, as what really matters is the ratios. So you can go to a 11-32 cassette as well, but then you are adding more costs, plus possibly a new chain depending on how short the old one is, plus possibly a medium or long cage rear derailleur to take up the additional range of the 11-32, depending on what you have now. I'd guess that the derailleur would probably me OK, since there is a smaller gap between the 53-39 than a 52-36.

You may or may not care about the gaps between cogs. If I was running 11 speed, I probably wouldn't care. I'm still on 9 speed, and I'm borderline whether I care or not. I'm actually (hopefully) going to be putting an 11-34 9 speed on my tri-bike to see how I like it, since I've switched to a 1x setup with just a 48T front ring. My existing 12-23 just won't get me up the hills around here without some serious strain. All depends on whether my derailleur will accommodate the 34t cog.

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