Shimano XT M8100 RT-MT800 Disc Brake Rotor

The Shimano XT RT-MT800 brake disc is a low weight disc with optimal heat dissipation and is designed to maximize your braking performance!

Hard material, optimally milled
The components of this disc are milled out of hard materials. This allows you to ride with harder brake pads than just the traditional Shimano Resin brake pads. Harder pads do not heat up as fast in long descents and have a higher durability.

Low weight
Shimano has done its best to keep this brake disc's weight as low as possible, without compromising its functionality. With this disc, you won't have to waste power lugging extra grams up hill while experiencing enough braking power going downhill.

Lockring variants
This brake disc is available in all sizes with a lockring that has internal teeth. This lockring is tightened with a cassette tool and is compatible with quick-release axles, as well as with 10 mm and 12 mm spindles.
This brake disc is also offered with a lockring with external teeth. This lockring is tightened with a bottom bracket tool and is used in particular with 15 mm axles, which are used mainly on mountain bikes. The lockring with external gearing usually fits bikes with 12 mm thru-axles as well. However, in a rare case on a road bike, it can rub against the front fork. Make sure to check if this space is very tight (1 mm - 2 mm space) or not. If it is, then we advise the lockring with internal teeth.

Weight of brake discs
• 203 mm: 164 grams
• 180 mm: 132 grams
• 160 mm: 109 grams
• 140 mm: 88 grams

Type of bike
These XT RT-MT800 discs are designed for the XT MTB series. They also work well on touring bikes, road bikes, and city and e-bikes.

Heat dissipation through Ice-Tech Freeza technology
These rotors feature Shimano's Ice-Tech Freeza heat management technology. The brake surface consists of 3 layers: 2 of stainless steel and 1 of aluminium. As a result the heat dissipation is very good, so you'll still have good braking power on long descents which require being on the brakes for a while. Brake fade as well as brake oil overheating is also less likely, so you can have more confidence in your braking power.

- Shimano RT-MT800 brake disc (including lock ring)

How do I mount a disc brake rotor?
For disc brake rotors, you have 2 different ways of mounting depending on the lock ring. One has an internal fit that you can tighten with a Cassette Removal Tool without a pin. If the inside of the key is open, it can reach far enough over the axle of the wheel. The other version is an external fit that you can tighten with a bottom bracket tool.