I have bought a Wahoo Kickr Core; I am seeking to get a cassette for my bike trainer.

I have a Felt F95 Bike Pic road bike with the following part details:

  • Rear Cassette - 8 cogs (The biggest cog has 23 teeth, smallest I think it was 11 teeth)
  • Front Cassette - 3 cogs
  • Gear Changers: Shimano Sora Flightdeck

Which cassette range is possible on a particular bike? and when would I need to buy a new chain?

  • 2
    Aside - consider getting a new one for your bike and put the old one on the trainer.
    – Criggie
    Dec 10, 2023 at 17:56

1 Answer 1


The easiest is to find the same cassette and to install it on the trainer (that you need to install with a 1.85mm spacer, normally in the box of the kickr): your derailleur is already tuned for this kind of cassette.

If you want to extend the range, then you indeed need a longer chain (so a new one), but most importantly, you need to make sure that the rear derailleur has enough capacity. If a short cage derailleur is fitted on the bike, it's possible that it won't handle larger cassettes (but to be more sure about that, it's necessary to have the exact reference of the derailleur).

  • I have the following Shimano Sora derailleur. I am not sure if this would support a 10 gear cassette ibb.co/0VfgHkw
    – ebe
    Dec 10, 2023 at 18:56
  • With a long cage, the number of gears will remain the same, what would change is the size of the cogs.
    – Renaud
    Dec 11, 2023 at 6:38
  • Staying with the original Sora derailleur probably means end of story at 27T, only the total capacity changes between SS and GS versions - see link to Shimano docs.
    – DoNuT
    Dec 11, 2023 at 7:29
  • Thanks for the addition, not knowledgeable on road groupsets. Note that increase range would be beneficial if you want to take full advantage of the trainer, as the kickr core can "simulate" up to 15% slopes, which would be very hard with the stock cassette (but you can also limit the max slope percentage).
    – Renaud
    Dec 11, 2023 at 7:57
  • hello @Renaud, DoNuT thank you for information. If I stay with the current Shimano Sora RD-3300 3x8 speed what cassette with how many cogs and number of teeth would you suggest? I am looking for a new cassette and chain. I would want to get the best of the 15% slope capability of the trainer
    – ebe
    Dec 11, 2023 at 19:39

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