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Mixing Cassette Cogs ?

mr_eddymr_eddy Posts: 811
edited August 2016 in Workshop
Hi All

I recently decided to swap out the cassette on my commuter road bike. It originally has a 3 x 8 speed setup using a 12-25 cassette however I was finding that I spent 90% of my time in the middle ring (39t). To that end I thought I could get a wider ratio cassette from my parts bin.

I had a old 8 speed sunrace 12-28 and a also a spare 11-25 SRAM 8 speed cassette. So basically I took the 8 speed Sunrace and took the removable 12t cog and replaced with the 11t cog from the SRAM. I have ended up with a Sunrace 11-28t Shimano compatible cassette albeit with a SRAM 11t cog at the front. My understanding is that the SRAM cassettes are also Shimano compatible in theory.

Only issue is that there seems to be some rubbing on a couple of gears - Before I start messing with the indexing (which I want to avoid if poss) can someone confirm if my mash up cassette should work with Shimano 8 speed shift gear ?



  • dj58dj58 Posts: 2,185
    Are you still predominately using the middle ring? If so what gear combinations does it rub in? Did you remember to adjust the B-tension screw on you rear derailleur to accommodate the larger 28T cog? Does your rear derailleur have the capacity to take an 11T cog?
  • crankycrankcrankycrank Posts: 1,830
    Also, different brands of cassettes can sometimes use different thickness spacers combined with different thickness cogs to achieve the same effective spacing as Shimano so you may have to measure the thickness of each and improvise.
  • mr_eddymr_eddy Posts: 811
    To be honest I have not adjusted b tension nor checked if my Rd will take a 11t will check this out tomoz. Thanks
  • mr_eddymr_eddy Posts: 811
    Ok just checked Rd is 11t and 28t compatible. It is noisy on 11 and 12 the most. I will play around with the b tension and see what happens. Ta
  • MatthewfalleMatthewfalle Posts: 17,380
    May also just need half a turn on limit screw - sort of annoying problem that requires hassle to get right.
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
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