Just discovered this very useful site, now for my 1st question.

I have a nice carbon bike with ultegra 6800 11 speed (11-32 cassette) I wish to use this bike on an indoor trainer (on Zwift) but wish to minimise wear. I planned to get a spare rear wheel (Shimano RS010) 11 speed hub and fit a trainer tyre. To save money I would fit a 105 5800 (11 speed) cassette on the RS010.

Obviously then just change rear wheel depending on road or trainer.

Ques: Do I need to stay with a 11-32 cassette or will I degrade gear changes by fitting maybe a 11-28 ?

Will I degrade gear changes by using the 105 cassette in place of the ultegra one ?

There is minimal wear on the existing components so mixing new & used hopefully will be ok ?

Advice and your thoughts appreciated.

  • Any 11-speed Shimano cassette will do. The main differences are weight build quality and material for the cheaper ones, which are irrelevant on a trainer. 11-28 or even 11-25 will give a finer adjustment of the load.
    – Carel
    Mar 2, 2016 at 15:01
  • If you have a very nice carbon bike, you may want to pick up a cheap bike to use in the trainer instead (or use rollers). Trainers are pretty hard on bikes, since bikes aren't designed to be clamped down while riding like a trainer does.
    – Batman
    Mar 2, 2016 at 20:24
  • 1
    Is there any proof that 'trainers are hard on bikes'? I've wondered about this before but can see no reason why it should cause problems. The loads that the bike is subjected to when on the road must be greater than on a trainer, where there are not the same impact loads. Mar 3, 2016 at 8:31

2 Answers 2


You should be fine using a 105 cassette on the turbo wheel. There will be wear to the chain, cassette and chain rings, but provided the drive train is clean and lubricated then this should be minimal. Doing what you've suggested is a good solution. Try to make sure if you use the bike on the road then the drive train is reasonably clean before swapping onto the turbo wheel and if one cassette becomes more worn than the other then replace it, or you might then have problems and cause more wear on the chain.

  • 1
    Thanks guys for those reassuring answers. I'm in my 60's and live close to the Yorkshire Dales hence the 11-32 cassette (pretty hilly) I don't race so the different variances between 11-28 and 11-32 is not really a factor. I'm pretty 'ocd' about keeping the bike clean so look go to go with this solution. Mar 2, 2016 at 13:47
  • Should read " so look good to go " Mar 3, 2016 at 7:47

Personally if I was riding an 11-32 on the road, I would want to train with an 11-32 as well, but either way, as long as you don't have any non-standard cage length, you will be perfectly alright to use the 105 5800 on the turbo wheel.

Gear changes should be fine and mixing components would be fine in this case, Wear to the components will be pretty much the same as riding on the road.


Since someone asked, the reason why I would personally prefer to keep my training cassette and my riding cassette the same, is because:

  1. 11-32 has different variances between gear changes as what 11-28 has
  2. You should usually train with what your ride (from a functional perspective)

If you train and do workouts on an 11-28 all the time, and then go on the road with the 11-32, you will soon find that you no longer have the often used 15, 17 mid-block gears. Instead, you'll jump from the 14 direct to a 16 and then to an 18 and that will affect your expected cadence.

For reference (showing Shimano CS6800):

11-28 (11-12-13-14   -15_\_-17_\_-19_\_-21_\_-23   -25-28)
11-32 (11-12-13-14   _\_-16_\_-18_\_-20_\_-22_\_   -25-28-32)
  • what difference would the 11-32 range make on the turbo trainer w/r to training?
    – OraNob
    Mar 2, 2016 at 11:45
  • @OraNob It will change the variances between gear changes.
    – RoKa
    Mar 2, 2016 at 12:03
  • @OraNob Updated the answer above for your perusal, in case someone finds it relevant to their question
    – RoKa
    Mar 2, 2016 at 12:23
  • 3
    But the trainer is not the same load as road ride with hills so it is not the same from a functional perspective.
    – paparazzo
    Mar 2, 2016 at 12:56
  • @Frisbee Sorry if it wasn't clear, but that's not what I meant with functional (bad choice of words). What I was referring to is if you do very focussed power zone training, it would be better to train on a rig where a button click would introduce an EXPECTED variance change (and therefore and EXPECTED cadence change), for e.g. from 110 to 102, instead of 110 to 95. Either way, I was only stating my preference.
    – RoKa
    Mar 2, 2016 at 17:46

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