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Replacing compact double 50 tooth cog

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Old 09-28-18 | 04:36 AM
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Replacing compact double 50 tooth cog

I have a Shimano compact double crankset with 50/34 cogs. Running brifters. I want to replace my 50 tooth cog on the crank. The original cog has the little chain ramp buttons on the inside. I have a new 50 tooth cog but it doesn't have the little buttons. Do you think it will shift ok or should I get one like the original with the little buttons ?
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Old 09-28-18 | 05:28 AM
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I've done it and it worked fine for me.
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Old 09-28-18 | 07:04 AM
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Using rings without the shift aids usually results in shifts that are both better and worse. Better in that no longer will the chain only climb up onto the larger ring at these shift points. Worse in that the rider often needs to learn how to help the shift with "soft pedaling" during the shift.

BTW one can file down the tops of pairs of teeth at a few locations along the ring to create a home made "W Cut" shift gate. I have done this many times on both self used bikes and for customers. Andy
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Old 09-28-18 | 10:31 AM
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A 50t ring designed to "mate" with 34t small ring will shift better than a ring without ramps and pins. This matters more since you are using brifters, whereas friction front shifting (with bar-ends or downtube) you'll always be able to shift fine. You live in Napa and have some nice bikes, and I'd recommend getting a chainring with ramps and pins. When you do, it's important that the orientation matches the smaller chainring correctly. With another brand, you may have to rotate the chainring to match the orientation of the Shimano.

A side note on terminology: the gears on the crankset are typically called "chainring" while "cog"or "sprocket" usually refers to gears on the rear wheel.
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Old 09-28-18 | 01:45 PM
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I will try the 50 tooth "chainring" (thanks TallRider, I call them all cogs ) without the ramp pins and see how it goes. I usually soft pedal when shifting so it sounds like I should be OK. If it doesn't work they way it should I will get the Shimano chainring. I had this brand new chainring without the pins one so thought I would use it if possible. Beautiful riding weather here in Napa Valley. Doing a ride by some of the vineyards tomorrow.
Thanks guys for the info !
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Old 09-28-18 | 07:01 PM
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Follow up on my chainring.
I put the new chainring on with no ramp pins today and took it for a test ride. I shifts great. Thanks for the help guys !
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