BMW 165mm Dry Clutch Steel Plate Product Introduction

Product Overview

This 165 mm dry single‑plate clutch is specially designed for BMW Boxer‑engine motorcycles, fitted for R850 / R1100 / R1150 / R1200C series. It adopts hydraulically‑actuated dry single‑plate construction; the clutch assembly runs dry without oil immersion. Torque is transmitted via friction between steel plates and friction linings. The original OEM unit is manufactured by ZF‑Sachs. Main OE part numbers in aftermarket: BMW OE 21217670454, Sachs 1864 000 124, TRW‑Lucas MCC608 kit.

Concept distinction:

Driven disc assembly: integrated unit of friction linings, base steel plate and torsional damping springs (21217670454 / 1864 000 124).

Clutch separator steel plates (pressure steel plates): quenched spring‑steel separator plates included in MCC608 kit, stacked and mated with friction plates.

Core Technical Specifications

Item	Specification
Clutch Type	Dry single‑plate clutch, hydraulic actuation
Friction Outer Diameter	165 mm
Spline Specification	17‑tooth
New overall thickness	Approx. 6.4 mm, wear limit 4.8 mm
Standard Operating Clearance	2.6±0.2 mm
Applicable Models	R850GS/R; R1100GS/RS/RT/S; R1150GS‑A/RS/RT/R; Full R1200C range

Substrate Material & Structural Features

Base Material Made of Si‑Mn spring alloy steel. Formed by stamping, stress‑relief annealing followed by plane quenching and tempering, delivering high flatness, elasticity and thermal warping resistance. For dry‑clutch application, flatness is critical. Thermal warping under repeated high‑temperature engagement is the most common failure mode.

Base Steel Plate of Driven Disc (BMW / Sachs Assembly) The base steel plate is riveted integrally with organic friction linings. Circumferential damping springs are embedded to absorb engine torque shocks and reduce gear‑shift judder. The steel plate surface is flat without grooves; torque is transmitted through friction linings on both sides. Oil contamination will cause immediate slipping and total failure.

Steel Separator Plates in TRW‑Lucas MCC608 Kit MCC608 is a complete overhaul kit containing full set of quenched steel separator plates and friction plates. Steel separators are precision surface‑ground to minimize thermal deformation. If original steel plates show warpage, scoring or heat discoloration, replacing friction plates alone cannot eliminate judder or slipping; full steel separator set replacement is mandatory.

Comparison of Three Mainstream Part Numbers

BMW OEM 21217670454 (Original Driven Disc Assembly) Manufactured by Sachs as BMW's OEM supplier. Base steel plate, friction compound and damping springs comply with OE standards. Delivers smooth engagement and excellent judder suppression. Higher cost, for genuine‑spec restoration.

Sachs 1864 000 124 (ZF‑Sachs OE Aftermarket Unit) Fully interchangeable with BMW 21217670454 with identical drawings, material and dimensions from original production line. Good thermal‑warping resistance. Preferred OE‑quality replacement for street and long‑distance riding with cost‑performance advantage.

Note: 21217670454 and 1864 000 124 are driven‑disc‑only assemblies, pressure separator steel plates are NOT included.

TRW / Lucas MCC608 (Complete Clutch Kit) Kit includes full friction plate set + full quenched steel separator set. Improved quenching process enhances anti‑warp performance compared to generic aftermarket parts. Optimized high‑temperature‑resistant friction compound. Ideal for high‑mileage full‑clutch overhaul when original steel plates are already warped and discolored.

Failure Modes & Assembly Instructions

Common Failures

Overload & high temperature → steel plate warpage and flatness distortion, causing clutch judder and uneven engagement.

Friction lining wear down below 4.8 mm thickness limit, insufficient torque transmission and slipping.

Fatigue of damping springs, resulting in take‑up judder.

Oil leakage contaminates steel / friction surfaces → slipping; full set replacement is required.

Assembly Notes

For dry clutch, do not touch friction working surfaces with bare hands; oil contamination must be strictly avoided.

Set operating clearance to 2.6±0.2 mm after installation.

Inspect steel plates for heat discoloration, warpage and scoring. Replace separator plates if deformation occurs; do not merely replace friction plates.

Organic friction material is sufficient for street use. Sintered‑metal friction kit is recommended for high‑power modifications and aggressive riding.