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Changing from 160mm to 140mm rotors

tyw214tyw214 Posts: 52
edited March 2017 in Road beginners
What do I need to watch out for in terms of compatibility if I want to change from a 160mm to 140mm rotors? or is that not possible because the 140mm won't be wide enough to reach the brake calipers? specifically on the CAAD12 Disc 105. It comes with 160mm, but I am thinking of changing them to the icetech 140mm rotors


  • compuwiz_ukcompuwiz_uk Posts: 139
    not up on the bike, but if its anything like the bikes i have then to drop to 140 rotor would need the caliper spacer removing from between the caliper & the frame. ( or an alternative spacer fitting if the spacer is also a converter to postmount etc )

    hopefully more knowledgable folks will be along soon to confirm or correct me if i am wrong :)
  • compuwiz_ukcompuwiz_uk Posts: 139
    OK, just had a gander at my bikes & they are a mixed bag of fittings.

    fronts all seem to have spacers to get to the desired sizes, BUT the problem is the rears, on one there is a spacer so down a size is possible but on the other there is no spacer & its the frame fittings that decide minimum disk size, on a couple others ( mountain bikes ) i would need a new fitting bracket if its possible as its a combined spacer/fitting bracket type to hold the caliper inplace

    so defo have a good look/post some pics of your current calipers ( front & back ) so the folks on here can better advise before you splash any cash :)
  • cougiecougie Posts: 22,512
    Why change?
  • timothywtimothyw Posts: 2,482
    From the pictures I've found it looks like there is an adapter on the front fork that could be removed to allow you to use a 140mm rotor (but you'd probably need shorter bolts for the brake caliper).

    It appears the rear caliper is attached directly to the frame, so you will not be able to make a change there (not without replacing the caliper anyway, and possibly using some kind of flat mount to post mount adapter).

    This is just based on eyeballing the stock photos though, so you'll need to do your own research.

    I have to ask though, why you want to do it? Brake performance will be worse, not better.
  • ugo.santaluciaugo.santalucia Posts: 28,031
    As above... why change to a less functional rotor? Don't tell me it's to save 10 grams
    left the forum March 2023
  • Man Of LardMan Of Lard Posts: 903
    Perhaps he wants to change, so it heats up more under braking and he can use it as a hotknife against anyone who gets too close :lol:
  • ryan_w-2ryan_w-2 Posts: 1,162
    I wonder why the 105 bikes come with 160mm and the Ultegra / DA bikes with 140mm?... Lower spec calipers perhaps?
    Specialized Allez Sprint Disc --- Specialized S-Works SL7

    IG: RhinosWorkshop
  • tyw214tyw214 Posts: 52
    Ryan_W wrote:
    I wonder why the 105 bikes come with 160mm and the Ultegra / DA bikes with 140mm?... Lower spec calipers perhaps?

    actually the caliper on the CAAD12 105 is weird. the front uses the Ultegra caliper, and the rear uses the 105 caliper...

    From the CAAD12 Disc 105 spec:

    Shimano BR785/505 Hydraulic Disc, 160/160mm

    Also, I changed because I don't feel like I ever need the 160mm on a roadbike.. ;x
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