Help I’m being dumb

vrsmatt
vrsmatt Posts: 160
edited April 2020 in Workshop
I have a 2015 Giant Defy Advanced 2 and I have just bought some new wheels and have dropped from 160mm 6 bolt rotors to 140 centrelocks

I totally forgot to consider the Caliper mounts as I wrongly assumed I’d just need to take off the old ones.

A quick browse of wiggle doesn’t yeild an immediate answer can someone post a link to what I need please?

To be clear I’m looking at a mounting solution not bigger discs

Cheers
Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway

Comments

  • vrsmatt
    vrsmatt Posts: 160
    Ps. 2015 means it’s pre flat mount so it’s the post type mounts
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • vrsmatt
    vrsmatt Posts: 160
    I already have the 140s on a set of wheels
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • veronese68
    veronese68 Posts: 27,324
    If it’s post mount it may not be possible to fit smaller rotors. If made for 160mm the calliper would need to move inward, are there adaptors that allow the calliper to sit closer to the frame than originally intended?
  • orraloon
    orraloon Posts: 12,687
    Why do you need to go from 160 to 140? Stay on 160 centrelock? Rotors not that expensive.
  • vrsmatt
    vrsmatt Posts: 160
    If it try to bolt direct to fork/frame it’s obvious it needs a spacer for the 140’s too. Just can’t find anything with a cursory search.

    I’ve messaged my LBS too who sold me the bike so we’ll see
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • whyamihere
    whyamihere Posts: 7,702
    Not all frames can take 140mm rotors. If for the 160s there is an adaptor between the frame/fork and the caliper, you just need to take that off and fit the caliper with shorter screws. If there's no adaptor, then the frame is only designed for 160mm rotors.
  • vrsmatt
    vrsmatt Posts: 160
    Guys I’m not asking if I want to use 160’s thanks 👍🏻 Just if anyone knows the answer

    I can always measure up and get the existing adapters machined if necessary
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • johngti
    johngti Posts: 2,508
    What are you asking then? It seems that the consensus is that as they’re post mount brakes, unless there’s an adaptor already there to allow 160mm discs to be fitted and that could be removed for 140mm then you’re not going to get 140mm discs to fit. The design of the post mount system won’t allow it whatever you get machined.
  • vrsmatt
    vrsmatt Posts: 160
    John, as I’ve said there IS an adapter on there already to fit the 160’s but when I take it off to mount direct there’s not enough room for the disc so it clearly needs a mount of some sort.

    Worst case scenario is to take 20mm off the face of each mount. Not a big problem just a pain in the ass
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • veronese68
    veronese68 Posts: 27,324
    There was no mention of it having adapters already until your 4th post, that's why you got the answers you did. It may be a case of changing the way the adapters are fitted, I vaguely recall some fitting in different dictions for front or rear and size of rotor. Mine is made for 160 and has no spacers so I couldn't tell you I'm afraid.
    If you do decide to machine the adapters just make sure it's done properly as you could have a nightmare lining the calipers up if not done correctly. Hope it's worth the hassle.
  • johngti
    johngti Posts: 2,508
    Apologies I misread. But I suspect that there aren’t any adaptors available - the only useful thing I’ve found is that post mount forks are designed either for 140mm or 160mm discs. You seem to be able to get something to go up a size but not down.
  • vrsmatt
    vrsmatt Posts: 160
    After an evening of internet searching I now know that the top end versions of my bike (with same f&f) came with 140mm Shimano hydraulics whilst mine came with the 160mm Spyres so I either didn’t get it lined up when I tried to bolt directly to the frame/fork or there’s deffo another adapter available somewhere.
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • vrsmatt
    vrsmatt Posts: 160
    Confirmed by LBS I just need the correct length bolts :-)
    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway
  • vrsmatt
    vrsmatt Posts: 160
    Just to follow through on this one



    Giant TCR Composite 1, Giant Defy Advanced 2, Boardman Comp, Santa Cruz Heckler, Raleigh M-Trax Ti, Strida LT, Giant Halfway