I'm trying to save costs so I want to upgrade to 7 speed 11-28 Cassette to keep the same shifters, dealer says I need a new Freehub, new 7 Speed Cassette, new chain AND NEW DISC BRAKES, why do I need new Disc Brakes? I already have them.

UPDATE: researching I've found it is a 6 Bolt Disc Brake (I added a new photo) so I think seller was trying to sell me what he had (Centerlock hub I think), not what I need (36H 6-Bolt rear hub).

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    Did you ask them why the disk brake replacement was required when you were given the quote? You appear to have an ISO hub, so I doubt it's a fitment issue. Maybe there is additional damage to the brake? Either way, asking them to explain the quote seems like a logical first step.
    – zenbike
    May 12, 2016 at 22:52
  • So to clarify, you're changing the cassette from a MZ-TZ21 14-28T 7speed to a new 11-28 cassette? You only need a new chain. Consider a second opinion from a trustable LBS.
    – Criggie
    May 12, 2016 at 23:39
  • MF-TZ21 is a Freewheel, I would like to upgrade to 7 Speed Cassette so I will need a new Freehub, new 7 speed 11-28 Cassette, new chain, what makes me feel confused is why do I need a new Disc Brake?
    – user20351
    May 13, 2016 at 3:38

1 Answer 1


Pretty sure that the MF series has the freewheel integrated with the cassette, so if you are going to a "pure" cassette, you will need to replace the freewheel and possibly the hub. You would need to replace the hub if you can't find a conversion to a non-integrated freewheel for your current hub. If the hub gets replaced, that could affect the disk as well. Does your current disk have an ISO 6 bolt pattern, or something else like Shimano's centerlock? If it's an ISO 6 bolt, you should not need a new disk with a new hub, assuming you get a hub with an ISO 6 bolt pattern.

  • Excellent point. If its some integrated nightmare, a whole new wheel might work out cheaper, and transfer the rotor/tyre/tube over.
    – Criggie
    May 12, 2016 at 23:44
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    It's hard to tell from your pictures, but you might not need one. As said above, if you have an ISO 6 bolt pattern on your current disk brake rotor, it should bolt right up to a new hub. May 13, 2016 at 3:41
  • Looking at the first picture I think I can see a bolt head at the back of the dropout, suggesting 6 bolt ISO. But you never know, with bike bits, it might be a new, cheaper 5 bolt one :)
    – Móż
    May 13, 2016 at 4:07

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