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I have a worn 52-tooth Shimano R7000 (105) chainring and I would like to replace it with a R8000 (Ultegra) 52-tooth ring. I am only looking to change the large chainring. I am in Russia and therefore I can only buy through alexpress.

Are these two chainrings interchangeable?

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    If you're buying an Ultegra chainring because you think it'll be an "upgrade" and somehow be better than a 105 chainring, prepare to be disappointed. The only reason it'll be better than your worn-out 105 chainring is it'll be new.
    – Andrew Henle
    Commented Mar 30, 2023 at 14:02
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    Consider that Aliexpress is not a reputable source, and your parts could range from complete knockoff to rejects, to adequate. Don't expect authenticity, and don't pay retail.
    – Criggie ♦
    Commented Mar 30, 2023 at 18:40

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Yes, the R8000 chainring is a direct and compatible replacement for the R7000 chainring. Shifting challenges could present themselves if the two chainrings are of a different tooth count, but being that they are both 52-tooth rings, your bike will not know the difference.

Shimano's compatibility chart shows the interchangeability of components of different groups, not parts with a single component. However, the R7000 and R8000 are just one level apart, are the same generation, and interchangeability of chainrings is pretty common, as long as the chainring mounting configuration is consistent (110/4 in this situation) and the tooth count is the same/close (for shifting performance and front derailleur compatibility).

Compatibility chart link

From the Shimano compatibility chart:

enter image description here

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    Does the Shimano compatibility chart cover mixing parts between different crankset versions?
    – Andrew Henle
    Commented Mar 30, 2023 at 14:05
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    @AndrewHenle - good question. As for MIXING parts within a component (FC - front crankset in this case), it is not a guarantee. However, the straightforward consistency of attachment of front chainrings brings a high degree of confidence to the recommendation. There are aftermarket chainrings that show the interchangeability of chainrings between these two levels (and a bunch of others as well). I would be more cautious about interchanging individual parts within a brake caliper, but chainrings should not be that critical. Same bolt circle and same generation (7000 and 8000) should be good.
    – Ted Hohl
    Commented Mar 30, 2023 at 14:39
  • @AndrewHenle - updated answer.
    – Ted Hohl
    Commented Mar 30, 2023 at 14:46
  • I'm dubious about the Ultegra chainring fitting properly on the 105 spider. I've had mountain chainrings from two different but closely related models. Both 9 speed and 104 BCD. The FC-M530 (unsure if this is the correct model number in this experience) large chainring would not fit properly on to my FC-M510 cranks (this model # is for sure correct) due to excess metal between the bolt hole and where it was supposed to mesh with the spider. It was only a mm or 2 and could easily be ground to fit (the M530 chainring had identical contours at the chainring - spider interface.
    – Jeff
    Commented Mar 31, 2023 at 1:45
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As a complement to Ted's answer, I would add that to confirm parts interchangeability between components, one can sometimes find the information into the exploded view (EV) document.

If we open the FC-R7000 EV, we can see a list of all the crankset's parts as well as two models of crankset that are officially made of compatible parts, the FC-5800 and FC-R8000.

enter image description here

Looking at the 52T chainring, we see a B in the FC-R8000 column, which means: Parts are usable, but differ in materials, appearance, finish, size, etc.

enter image description here

This confirms that you can use it without problems for your FC-R7000 crankset.

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