Analyzing The Compatibility of Shimano Rotors and Hope Brakes

Hope brakes can be used with Shimano rotors when the diameter and the thickness of the rotor are compatible with the brake caliper in question.

That said, the expected performance of Hope brakes is guaranteed only when the brakes are coupled with the rotors specifically designed for them.

Requirements For Brake Rotor Compatibility

In order for a rotor to be compatible with certain disc brake calipers, it has to meet the following criteria:

The Right Size

If the rotor is too large for the brake, you won’t be able to install the wheel on the bike or there will be severe rubbing.

For that reason, it’s necessary to find the original rotor size that the brakes are built for.

There are three ways to acquire that information:

a. Read the label on the old rotors that you’re replacing.
b. Search the brake model online.
c. Ask a bike shop

It’s possible to upgrade to larger rotors by installing an adapter increasing the distance between the brake calipers’ mounting points and the caliper itself.

The adapter that you need depends on the brake mounts, the default rotor size that the brakes are designed for, and the size of the new rotor.

There are three main disc brake mounts:

  1. International Standard (IS)
  2. Post Mount (PM)
  3. Flat Mount

International Standard is found on older forks and frames. In that case, the disc caliper attaches to the bike via bolts threaded perpendicularly to the mount.

IS mounts

Post Mount is found on modern bikes and operates with bolts going straight into the mounts.

Post Mount

If you have PM mounts designed to run 160mm rotors by default and want to upgrade to 180mm rotors, for example, you will need a 20mm post mount adapter.  

Flat mounts are a new disc brake standard limited to 160mm rotors and normally found on road bikes.

A fork with flat mounts

Rotor Size Comparison

Hope rotors are available in the following sizes – 140, 160, 180, 183, 185, 200, 203, 205, 220 and 225mm.

Meanwhile, the sizes of Shimano rotors are – 140mm, 160mm, 180mm, 200mm, and 220mm.

If the original Hope rotors correspond to one of the Shimano sizes, size compatibility will not be an issue.

Hub Compatibility

The method used to mount the rotor to the wheel’s hub influences compatibility too.

Currently, there are two main options:

  • Bolt-on
  • Center-lock

Bolt-on rotors attach to the hubs via bolts. Centerlock hubs use a Shimano patented technology and are secured to the hub via a lock ring similar to that of a cassette.

If you have bolt-on hubs, you will need a bolt-on rotor.

If you have a center-lock hub, you have two options:

  • Install center-lock rotors
  • Install bolt-on rotors via an adaptor

Rotor Thickness

Another important parameter is the thickness of the rotor. If a rotor is too thick or too thin, the brake modulation of the bike will suffer.

Modulation is a term describing the control over the braking force. For optimal braking, medium modulation is desired.

If the rotor is too thick, the brake pads will grab it faster than necessary, and the brakes will feel as if they’re operating in on/off mode with nothing in-between. This is an example of insufficient modulation.

If the rotor is too thin, the brake pads will have to travel more to grab it. Thus, the user won’t be able to generate maximum braking power on time. (This is an example of too much modulation.)

Luckily, standard Hope and Shimano rotors are of the same thickness – 1.8mm. Thus, from that perspective, most Hope and Shimano rotors are interchangeable.

That said, Hope has some thicker rotors like the V4 models which are close to 3mm thick and compatible only with the original calipers.

Obviously, if the brakes are designed for a rotor of that thickness, the user shouldn’t rely on 1.8mm rotors.

Brake Track Width

Another parameter to look at is the width of the brake track.

The brake track is the part of the rotor that the brake pads squeeze. If the brake track is too narrow, parts of the pads will be left “hanging”.

This phenomenon is known as brake pad overhang and can have a detrimental effect on a brake.

The parts of the pads that aren’t touching the rotor never wear out. Meanwhile, the other sections of the pads get smaller with time due to the friction against the rotor.

Eventually, the sections of the pads that don’t wear down touch. When that happens, the operational segments of the pads will be unable to grab the rotor with enough strength. Thus, the brake will no longer be functioning.

To minimize the possibility of this outcome, it’s advisable to measure the brake track of the current rotors and compare it to that of the new ones.

Note: Sometimes brake pad overhang is the result of inappropriately large brake adapters moving the caliper too far from the rotors and thus leaving the pads “hanging”.

Brake Pad Material

Brake pads are divided into two categories:

  • Organic/Resin
  • Metal/Sintered

Most rotors can operate with both types. One exception would be Shimano’s entry-level rotors which are softer and labeled as “resin only”. Using them with metal pads would cause premature wear.

If you’re going to switch from one type to the other, it’s recommended to softly sand the rotor, thoroughly clean it, and bed the pads.

Summary: What You Need To Know

Shimano rotors will operate properly with Hope brakes when the following criteria are met:

  • The diameter of the rotors should match the one supported by the brakes. If a bigger rotor is needed, the user can install an adapter.
  • The thickness of the rotors should also be compatible with the brakes. Thin rotors result in extra modulation. Thick rotors decrease modulation.
  • The brake tracks of the rotors should be of similar size or else brake pad overhang might take place.
  • The material that the rotors are made of should be compatible with the pads. Lower-end Shimano rotors are designed for resin pads only.

The optimal performance of Hope brakes is guaranteed only when the brakes are used with the original rotors designed for them. That said, people have successfully used rotors from other brands including Shimano.

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