# Fc-9000 50/36?



## stemarcoh (May 1, 2015)

Hi, has anyone tried to combine a 50T with a 36T chainring on an FC-9000 crank? I have a 50-34T currently. I know the Shimano docs warn against their "non-standard combinations but I can't imagine why a 50-36T wouldn't work. Thanks!


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## nhluhr (Sep 9, 2010)

The Dealer Manual warns:

"Be sure to use the specified gear tooth combination. If an unspecified gear is used, the chain may enter between the gears, damaging them."

And I was able to dig around the web to find a couple decent pics of the 52-36 and the 52-38 to see what might make the various rings compatible with each other and I paired them together in this animation:










You can see the black carbon angled 'shelf' or whatever that ramps from the inner ring to the outer ring is matched in diameter to the intended inner ring that it's paired with. That makes sense. You want the chain to ride a smooth path up and down so it's less likely to jump out of control (or, as they mention, gets jammed between them in a too-wide gap).

Now your question about pairing the 50 and the 36? I'm guessing the 36 inner ring will be 'too high' for the ramp/shelf/thing on the 50. It'll probably shift but it won't be as good. Certainly not as smooth and free of chaindrop as you may be used to and it might jam in between the now wider gap above the 36t ring to where it would meet the 50's shelf/ramp.


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## Merc (Oct 9, 2011)

I have a few bikes with the DuraAce 9700 crankset installed and for each one I changed the inner ring from a 39T to a 36T. So I am now running a 53T and 36T and it shifts perfectly.


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