Author Topic: Shimano, 8 to 9 speed.  (Read 480 times)

Shimano, 8 to 9 speed.
« on: April 27, 2020, 03:59:56 pm »
On my British Eagle Touristique I fitted a 105 hub, c.2015, but for some reason I only put an 8 speed cassette on.  This gives it 16 gears which is perfectly adequate for me out on the road and in fact give a beautiful, trouble-free shift with nice intervals.

Unfortunately my turbo trainer needs a nine speed cassette.  I'm guessing moving to 9-speed is not worth the hassle just for the turbo.

I can go on using my tourer on the turbo, ok, but I have gone off triples.

Sic transit and all that..

Re: Shimano, 8 to 9 speed.
« Reply #1 on: April 27, 2020, 06:29:50 pm »
surely you can fit an 8s cassette on the turbo? It'll go straight on to the same body as a 9s cassette will?

The other option is to use a 9s chain on the bike when it is on the turbo; probably the 8s indexing will work over two or three sprockets well enough, and this might be enough for turbo use. If you use a quicklink it won't take long to swap chains, and it'll probably run well enough on 8s chainrings for turbo use....?



  • Randonneur and bargain hunter
Re: Shimano, 8 to 9 speed.
« Reply #2 on: April 27, 2020, 08:27:40 pm »
Sounds like it's bad information from the turbo maker to me. Put a freehub spacer on just as you would when putting an 8s cassette onto a regular wheel. If it doesn't work then that is a very odd arrangement.

Perhaps the manufacturer/brand's instructions don't account for using a spacer.
YACF touring/audax bargain basement:

Ban cars.

Re: Shimano, 8 to 9 speed.
« Reply #3 on: April 28, 2020, 09:55:29 pm »
No, no spacer mentioned.  Just said use 9 or 10 speed.

I am sure I only need 8 speed and will try it next time I take the bike off.

Thanks for the replies.
Sic transit and all that..


  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Shimano, 8 to 9 speed.
« Reply #4 on: April 29, 2020, 10:33:29 pm »
If your trainer takes a max 9 or 10 cassette - not 11 speed capable - then no spacer is needed to fit an 8.

8 & 9 cassettes are the same width. 10 is approx 0.5mm narrower and is usually supplied with the correct shim.

If 11 speed capable then a 1.5mm spacer is needed (and usually supplied) to fit 8, 9 or 10 cassette.


Well that's the more blunt way of putting it but as usual he's dead right.

Re: Shimano, 8 to 9 speed.
« Reply #5 on: May 03, 2020, 11:31:47 am »
Thanks, that's proved to be the case!  Shame the instructions aren't as helpful ::-)
Sic transit and all that..