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Condensed answer:

Shimano rotors can work with TRP brakes only when the following conditions are met:

• The brake models are designed to operate with 1.8mm thick rotors.
• The diameter of the rotor is the correct size for the particular brake setup.
• The hub is compatible with the mounting mechanism of the rotor, usually Centerlock.
• The rotors are compatible with the brake pad material.

In all other cases, Shimano rotors are unsafe or won’t fit.

Rotor Thickness Is Important

Disc brake calipers are designed to operate with rotors of a certain thickness.

If the rotor is too thick, the brake pads may have insufficient clearance and cause persistent rubbing.

If the rotor is too thin, there’s “dead space” between the brake pads and the rotor’s brake track resulting in a slower response rate and braking.

When the rotor wears down and gets even thinner, the braking will become even less efficient.

For that reason, it’s necessary to always use rotors of the correct thickness for your calipers.

Shimano rotors are 1.8mm thick. Consequently, they are only compatible with TRP brakes designed for 1.8mm thick rotors.

Below is a list of TRP brakes that fit that criteria:

• TRP Slate T4
• TRP Spyke
• TRP Hylex RS Black
• TRP Spyre SLC
• TRP HY/RD
• TT Hydro HD-T910

The table below contains the basic characteristics of the brakes in the list:

Rotor Diameter and Caliper Compatibility

If the rotor isn’t the right size for the brake setup, the user will experience difficulties.

Option 1: The Rotor Is Too Small

If the brakes are set to operate with 180mm rotors, and the user tries to use 160mm rotors, the new ones will fit but will cause brake pad overhang.

Brake pad overhand is a phenomenon during which a section of the pads never gets in contact with the rotor. As a result, that section remains the same thickness while the rest of the brake pad gets smaller and smaller with use.

At one point, the unworn sections of the pads will press against each other. Since their thickness will be greater than that of the unworn parts, the brakes will be unable to grab the rotor sufficiently, and the rider will experience a massive loss of braking power.

For that reason, it’s very important to avoid using rotors that are too small for your setup.

Option 2: The Rotor Is Too Big

If the rotor’s diameter is too large, the user will be unable to fit the wheel onto the hub because the rotor will bottom out against the brake caliper.

This issue can be circumvented by using an adapter that increases the distance between the caliper and the rotor.

The adapter that you need has to answer the following criteria:

• It has to be made for the mounts that you have.
• It has to increase the distance between the caliper and the rotor’s periphery by the difference between the old and new rotor’s diameter.

Currently, there are three types of mounts:

International standard. The brake caliper is attached to the frame and fork via bolts screwing perpendicularly to the mount. This is an older standard, and you will not find it on modern suspension forks.

Post Mount (PM). This is the most common disc brake mount. The caliper is mounted via bolts going directly into the mount.

Flat mount (FM). This is a fairly new disc mount common for road bikes. The mounts are very slick and discrete. Flat mounts are limited to 160mm rotors.

Here’s a hypothetical scenario.

You have 160mm rotors and post mounts. Your goal is to upgrade to 180mm rotors. In that case, you will need a +20mm PM (post mount) adapter.

Note that the TRP brakes in the table above are designed either for post or flat mounts.

The Brake Pad Material Matters Too

There are two types of brake pads based on the material that they are made of:

• 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.

The TRP brakes compatible with Shimano rotors use metal or semi-metallic pads.

Since all TRP brakes compatible with Shimano rotors use pads with metal in them, it’s recommended to stay away from the Shimano rotors designed for “resin-only pads”.

Below is a list of those rotors:

• Shimano SM-RT30
• Shimano RT10M 
• Shimano SM-RT70
• Shimano Deore SM-RT54-S 
• Shimano Tourney TX SM-RT10
• Shimano Altus SM-RT10-M

The Hubs and the Rotors Have To Be Made For Each Other

If the attachment mechanism of the rotor and the hub do not match, you will not be able to mount the rotor.

There are two attachment methods:

• Centerlock
• 6 Bolts

Many Shimano rotors use a patented system known as Centerlock. Centerlock hubs have splines on which the rotor slides. Then, a lockring secures the rotor to the hub. The principle is similar to the installation of a cassette.

If the hub isn’t made for Centerlock rotors, then it won’t be possible to install a Centerlock rotor on it.

However, it’s possible to install a bolt-on rotor on a Centerlock hub with the help of an adapter.

Final, non-condensed answer

Shimano’s rotors are 1.8mm thick and are therefore compatible only with TRP brakes designed for 1.8mm rotors.

Those models are:

• Slate 4
• Spyke
• Hylex RS Black
• Spyre SLC
• HY/RD
• Hydro HD-T910

Since all models above are designed for brake pads with metal in them (metal or semi-metallic), it’s NOT recommended to use Shimano’s resin-only rotors (you can find a list of those higher in the post).

The rotors have to answer two more requirements:

• They have to be the correct diameter. (Too small = brake pad overhang; Too large = can’t fit)
• The rotor mounting system has to be compatible with the hubs (Centerlock or 6-bolt).

Frequently Asked Questions

What is the advantage of using Shimano rotors with TRP brakes?

The only advantage is availability. If you can’t find TRP rotors, you will have one more option. If you are touring in the middle of nowhere, for example, it’s nice to have alternatives.

What are the downsides of using Shimano rotors with TRP brakes?

The main issue is that you’re limited only to the TRP brakes listed above. If you want to use a TRP brake that isn’t on the list, you will need to get the recommended rotor for it.

What would happen if I combine 1.8mm rotors with brakes designed for 2.3mm rotors?

If the brake pads can be pushed close enough to the rotors, the combination could work but only for a while.

This practice is not recommended because the rotors will quickly become too thin for the pads to grab them sufficiently. The outcome will be brake pad overheating and loss of braking power.

2.3mm rotors have to be replaced when they reach 1.8mm thickness. Thus, you will be effectively using worn rotors from the get-go.

What does TRP stand for?

TRP stands for Tektro Racing Products and is part of the large Taiwanese company TEKTRO. The TRP line is race-oriented and thus focuses on making light and efficient components.

What is the advantage of switching to a larger rotor?

A larger rotor has a longer radius and thus provides more leverage against the wheel. In other words, a larger rotor offers more braking power.

For example, a 203mm rotor is expected to provide 23% more stopping power than a 160mm unit.