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I have new Trek Émonda SL 5 Disc 2022 size 58 which comes with Shimano 105 Groupset and CS-R7000 11-30T cassette. https://www.trekbikes.com/us/en_US/bikes/road-bikes/performance-road-bikes/%C3%A9monda/%C3%A9monda-sl/%C3%A9monda-sl-5-disc/p/32560/

I want to get another cassette for my Tacx 2T Neo trainer.

CS-R7000 is not available so I was thinking of buying Ultegra - CS-R8000 11-30T cassette and using it for road while putting the CS-R7000 on the trainer.

Will swapping between CS-R7000 & CS-R8000 be possible? Do I need to change the chain or any other part or I can just swap the cassettes?

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  • Thanks to all the folks who answered! I'm using the CS-R8000 for few months now. The installation went smooth. I'm swapping the bike seamlessly between the Tacx trainer with CS-R7000 and the tire with CS-R8000. Apr 26, 2022 at 7:04

3 Answers 3

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Shimano produce a compatibility chart for its products: https://productinfo.shimano.com/#/com?cid=C-453&acid=C-454

It shows that these cassettes are compatible and you can just swap the cassettes.

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You can swap any road cassette from Shimano and SRAM on your bike, provided they have the same number of sprockets, of course. They are interchangeable.

You might check the chain stretch of your existing combination and also consider replacing the chain.

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  • 1
    Don't forget the different freehub bodies between the two manufacturers.
    – MaplePanda
    Mar 8, 2022 at 18:55
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    @MaplePanda: not a problem with Shimano 105! They have 11 sprockets max. and are perfectly interchangeable SRAM 10 or 11 speed. Different for MTB drives though.
    – Carel
    Mar 9, 2022 at 21:33
  • Ah yes, good point. I was thinking of the new 12 speed Shimano road freehub, but that is not applicable here.
    – MaplePanda
    Mar 10, 2022 at 0:00
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To elaborate on the issue of the chain: 11s and higher chains should be replaced at 0.5% wear. If they are replaced after this, e.g. at the 0.75% wear limit that was common for 10s chains, there is a risk that the cassette is worn enough that a new chain will skip.

A chain checker is a good investment for many cyclists, as it allows us to quickly check if the chain is Ok. I would recommend checking your chain, or asking a shop to do that. If it’s under 0.5% wear, there’s no issue in just substituting the cassette - provided the cassette is the same size.

You currently have an 11-30. If you bought an 11-32, the chain would be a bit too short, but it would probably shift OK if you avoid the big-big combination. The same would be even more true if you bought an 11-34.

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  • 11-34 could cause trouble with a short cage rear derailleur, a B-screw tweak could help but not in all cases.
    – Carel
    Mar 9, 2022 at 21:35
  • @Carel Whoops ... the Emonda is specced with a short cage RD. I have long-cage RDs on all my bikes, so I missed this. It is actually possible the short cage RD would shift fine, but it is definitely 4 teeth beyond the max spec for the big cog.
    – Weiwen Ng
    Mar 10, 2022 at 0:26
  • I tried it and it works fine. However shifting is not as smooth as the 105 cassette so I reverted back to it for outdoor and use the Ultegra for indoor training only. Jan 17, 2023 at 18:33

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