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I need to replace my outer chain ring.

I am currently running a 50t, I'm pretty sure it's a 130 BCD.

I am considering a SRAM Outer chain ring as a replacement. I assume as long as measurements are the same I Should be OK. The description says (not for 2012+ 'New-Red' cranks with hidden-bolt spider) so that's positive I think for my purpose. Here's the info on the SRAM ring I'm looking at: http://prntscr.com/8fwk1u

  • actually i'd like to even have confirmation that that chain ring actually comes in 130 BCD with 50t... not sure it even do! – topwik Sep 13 '15 at 19:13
  • Have a look at Specialites TA. They have odd sizes and have compatible models for most of cranks. – ojs Sep 13 '15 at 20:31
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You can use the chainring, but each brand (Shimano, SRAM, etc...) aligns the shifting ramps and pins to work best with their own brands inner rings. So the indexed shifting will not be as fast/smooth as when you would use the same brand of rings together.

Inner rings frequently have individual teeth shaped so that the chain will lift off and drop down faster in certain positions. These teeth are lined up with the ramps and pins on the outer ring, to facilitate faster/smoother shifting. If you pair a SRAM outer with your Shimano inner, these teeth will not line up correctly. It won't make the shifting not work, but it will just not work as well. The X-Glide road rings are also designed for 11-speed, Yaw front shifting; your're paying for tech/features that your bike can't fully utilize.

Also, you are right, X-glide rings do not come in 50T, 130BCD combinations. You'd have to go with a 53 or larger size.

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  • cool, thanks for the info, I am also considering a 50t 130 bcd shimano 105 outer ring as a replace. The stock on my bike is Tiagra. That would probably work better. Also the stock on my bike is 9speed and the 105 ring replace is for a 10sp. Can't find much for 9speed anymore, – topwik Sep 14 '15 at 2:57
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    The "speeds" of the chainring will not make any real difference between 9 and 10 speed. I frequently run 10-speed chains on my 9-speed city bike. It may be purely imaginary, but the shifting feels smoother, and runs a little quieter. – JonR Sep 15 '15 at 0:21

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