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R8000 chainrings on R7000

Old 07-25-21, 07:20 AM
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AMoney
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R8000 chainrings on R7000

I'm looking at getting a bike with a 105 R7000 crankset. I'm thinking about swapping the 50/34 for a 46/36. I know that this combination isn't offered in a 105 groupset but is offered in an Ultegra groupset. Would 46/36 Ultegra R8000 chainrings work on a 105 R7000 crankset? Thanks.
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Old 07-25-21, 08:14 AM
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The only for sure info I could find is all 7000 can be used on 8000 crank so would be safe to assume the reverse is true and the 8000 only comes in one version to use with all chainring combos. From Shimano.EV-FC-R7000-4331A.pdf (shimano.com) You could also just contact Shimano directly to confirm.
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Old 07-25-21, 11:08 AM
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It might work but why not just buy a complete Ultegra chainset? The difference in finish alone would annoy me and I doubt the price differs much.
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Old 07-25-21, 01:31 PM
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I put Ultegra R8000 52/36 rings on my 105 5800 crank that originally was 50/34. The profile of the spokes does not match up, but I doubt any can tell while I'm pedaling.

The only thing I would double check is that the bolt circle diameter BCD or pitch circle diameter PCD isn't different on that crank that has the 46/36 rings. I think on their product page, Shimano gives you that info.

But if finish color or the profiling discrepancy is going to bug you, then don't do it.
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Old 07-25-21, 01:31 PM
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It works. I've done it.
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Old 07-25-21, 02:16 PM
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Originally Posted by hounslow View Post
It might work but why not just buy a complete Ultegra chainset? The difference in finish alone would annoy me and I doubt the price differs much.
That's a good idea. I looked at the price of a 46 tooth Ultegra chainring. I was somewhat surprised that it is almost as expensive as an Ultegra crankset. If I decide to swap out components, I would very likely get a new crankset instead of just getting chainrings.
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Old 07-25-21, 04:08 PM
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Originally Posted by AMoney View Post
That's a good idea. I looked at the price of a 46 tooth Ultegra chainring. I was somewhat surprised that it is almost as expensive as an Ultegra crankset. If I decide to swap out components, I would very likely get a new crankset instead of just getting chainrings.
If you don't want the other crankset you can probably sell it on eBay for the retail price of the new crank. People were paying MSRP for used bike stuff on eBay long before COVID.
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Old 07-25-21, 05:30 PM
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Originally Posted by Iride01 View Post
If you don't want the other crankset you can probably sell it on eBay for the retail price of the new crank. People were paying MSRP for used bike stuff on eBay long before COVID.
I was thinking the same thing. Great minds think alike. :-)
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