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I bought and installed Shimano MT200 brakes to my bike and now I'm wondering are they installed correctly. Seems like only small area of pad is touching the rotor. 160 mm rotor in the front. I had some bad Tektro mechanical brakes but replaced them with these Shimano MT200 hydraulic ones.

Pictures of different angles: https://imgur.com/gallery/WAiZkjc

front brake

side view

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    Is that a post mount brake on an IS frame? – gschenk Oct 3 '20 at 14:09
  • Yeah I had tektro mechanical and replaced them with Shimano mt 200. – MT247 Oct 3 '20 at 14:20
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    I wonder how it worked before with previous brakes. Has the adapter also been repositioned? Apparently, more than one part has been moved or replaced, not just the caliper. – Grigory Rechistov Oct 3 '20 at 16:20
  • That adapter came with shimano. Previous tektro adapter looked similar though. Maybe I should try tektro one if flipping this shimano does not work. – MT247 Oct 3 '20 at 17:06
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    I think I fixed it now. I just had the adapter wrong way. imgur.com/gallery/AXwGxUr – MT247 Oct 3 '20 at 20:29
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[This answer is based on OP's pictures and comments about what worked in the end]

The fork has IS brake mount interface, the brake caliper is for PM (post mount) interface. An adapter to keep them together is required.

IS/PM adapters come in many variants. The main difference between them is the disc diameter difference they dictate. Just a few examples (the image taken from one of discount retailers) of visual differences between such adapters is demonstrated below. Compare No. 1 — No. 3 (No. 4 seems to be a PM/PM adapter):

some of adapters

An adapter marked as "+0 mm" incurs no difference in disc size. That means, if the wheel has 160 mm disc installed, it will work a fork meant to have 160 mm rotors and with +0 mm adapter. An adapter marked as "+20 mm" will require 180 mm disc to match the rest of the same setup.

Now, the trick is that the same IS/PM adapter part is asymmetric and can provide two offsets, depending on the direction it is installed.

Compare two pictures from the @MT247 question and comments.

  1. Adapter installed in the supposedly +20 mm position. The caliper sits too high relative the the disc, resulting in very little overlap between surfaces of brake pads and the 160 mm disc.

Wrong!

  1. The same adapter reversed and installed in the +0 mm position. The caliper allows the whole surface of brake pads to touch the 160 mm disc when braking.

Correct

Another, very confusing, culprit is that a different adapter should be installed in the back of a bike compared to what is installed in the front! That is, to work with a 160 mm rear disc and an identical caliper, a different IS/PM adapter may be required.

The key here is to carefully read the manufacturer's installation instructions and use common sense when inspecting the brake setup: brake pads and the disc must overlap over the whole area.

  • Thank you for this, the problem was that there were no instruction with these and that adapter was just plain black and there were no arrows or anything about which side should be up. – MT247 Oct 4 '20 at 11:26
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Your brake is certainly not properly set up. Do not ride the bike in this state!

The rotor's brake track must run fully between the brake pads. The radial dimension of both match.

You rotor may be too small for the brake it its present set up, your wheel not properly inserted, or the brake caliper not mounted correctly.

Check your brake's manual for adjusting it to different rotor sizes with adapter plates. Often an adapter can be flipped to accommodate 140 mm and 160 mm rotors.

As general advise: do not fix it yourself.

Ask someone who knows what they are doing, for example, a certified mechanic. That you have to ask this question indicates you are not ready to tinker with brakes that are relevant to rider's safety.

  • Yep it's 160mm rotor in the front. Should I buy bigger one? – MT247 Oct 3 '20 at 14:18
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    @MT247 If unsure while working on brakes, ask a qualified cycle mechanic. It can become a matter of life and death, not trying to sound dramatic here. It is. – Carel Oct 3 '20 at 15:15
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    @MT247 There is no need to buy a new rotor to compensate for improper installation of the existing one. Fixing the existing setup is more beneficial in any regard. – Grigory Rechistov Oct 3 '20 at 16:22
  • I think I fixed it now. I just had the adapter wrong way. imgur.com/gallery/AXwGxUr – MT247 Oct 3 '20 at 20:29
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    @MT247 you should add that as an answer - it will help any new searchers in the future. – Criggie Oct 4 '20 at 0:16
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There are too many spacers, and/or too small of a rotor.

Don't ride it this way, get it fixed first.

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