The Shimano Deore XT BB-MT800-PA bottom bracket is a Press-Fit HOLLOWTECH II bottom bracket designed for MTB drivetrains fitted with Shimano cranksets with a 24 mm axle. Part number IBBMT800PA, it is intended for frames with an 89.5/92 mm compatible Press-Fit bottom bracket shell.

Part of the Deore XT ‘Shimano ’ range, this bottom bracket features high-quality sealed bearings and an optimised design to ensure smooth crankset rotation and efficient power transfer.

The BB-MT800-PA is therefore an excellent solution for replacing a worn bottom bracket on a mountain bike fitted with a compatible Shimano HOLLOWTECH II crankset.

HOLLOWTECH II technology for efficient power transfer

The Shimano BB-MT800-PA utilises HOLLOWTECH II technology, developed to ensure a good balance between stiffness, efficiency, weight and smooth rotation.

The system’s design features bearings positioned outside the central area of the bottom bracket to provide effective support for the bottom bracket axle. Shimano states that its Press-Fit technology uses widely spaced bearings to help ensure efficient transmission of pedalling power.

For the cyclist, this results in a smooth pedalling action and a good sense of efficiency, which is particularly appreciated in mountain biking where efforts are repeated and riding conditions are demanding.

Press-Fit bottom bracket 89.5/92 mm

The BB-MT800-PA is designed for frames fitted with a Press-Fit standard , with a bottom bracket width of 89.5 or 92 mm and a 41 mm bore diameter.

It is therefore essential to check the frame standard before purchase. A Press-Fit bottom bracket cannot be fitted to a frame designed for a traditional threaded bottom bracket.

The part number BB-MT800-PA should also be distinguished from the BB-MT800-PC, which is intended for a different Press-Fit bottom bracket width. Shimano lists the BB-MT800-PA for widths of 89.5/92 mm.

Compatible with Shimano cranksets with a 24 mm axle

The BB-MT800-PA is designed for Shimano MTB cranksets with a 24 mm axle. Shimano recommends it in particular for use with various cranksets from its HOLLOWTECH II-compatible MTB ranges.

In particular, it can be used with Shimano cranksets such as the Deore XT FC-M8000, as well as with several compatible Shimano models fitted with a 24 mm axle. Compatibility must always be checked based on the crankset and the frame standard.

Sealed bearings for long-lasting performance

The Shimano Deore XT BB-MT800-PA features sealed bearings, designed to minimise the bearings’ exposure to external contaminants.

In mountain biking, this feature is particularly beneficial: mud, dust, water and spray can quickly affect the components around the bottom bracket. Good sealing therefore helps to maintain smooth rotation and extend the bottom bracket’s lifespan.

As with any Press-Fit bottom bracket, however, its lifespan depends heavily on the condition of the frame, the quality of the installation and the conditions of use.

Expert tip: on a Press-Fit bottom bracket, the quality of the installation is just as important as the bottom bracket itself. The cups must be fitted perfectly in line with the axis, using the correct tools, without striking the bearings or cups directly.

When replacing the bottom bracket, take the opportunity to check the condition of the frame housing, clean the contact surfaces thoroughly and check the condition of the seals. If the old bottom bracket has play or is creaking, it is also worth checking for any wear or deformation of the Press-Fit housing.

Technical specifications

• Brand: Shimano
• Range: Deore XT
• Model: BB-MT800-PA
• Part number Shimano: IBBMT800PA
• Type: Press-Fit bottom bracket
• Technology: HOLLOWTECH II
• Use: Mountain biking
• Axle type: 24 mm
• Frame bottom bracket width: 89.5 / 92 mm
• Bottle cage diameter: 41 mm
• Bearings: sealed bearings
• Mounting: Press-Fit
• Standard: PF41 – 89.5/92 mm
• Manufacturer’s weight: approx. 69 g
• Colour: black
• Product code: IBBMT800PA

Shimano states an average weight of 69 g for the BB-MT800-PA in its technical documentation.

Key features

• Shimano Deore XT range, renowned for its reliability.
• Compatible with Shimano MTB cranksets with a 24 mm axle.
• HOLLOWTECH II technology.
• Sealed bearings.
• Press-Fit 89.5/92 mm standard.
• 41 mm bearing housing diameter.
• Designed for mountain bike use.
• Ideal solution for replacing a worn or loose bottom bracket.

In summary

The Deore XT BB-MT800-PA – IBBMT800Shimano is a HOLLOWTECH II Press-Fit MTB bottom bracket designed for Shimano cranksets with a 24 mm axle.

With its sealed bearings, 89.5/92 mm size, 41 mm housing diameter and Deore XT design, it is a reliable solution for replacing a worn bottom bracket on a compatible mountain bike.