Get the most from your BMW
Vehicles with a manual transmission use a clutch and flywheel to change gear. The clutch and flywheel have a central hole so they are able to slide onto the input shaft and sit against the bell housing.
What's all the 'Clutch' fuss?
The clutch sits between the flywheel and the gearbox. It allows gears to be changed within the gearbox by separating it from the rest of the transmission when the clutch pedal is pressed.
It is made up of a pressure plate, clutch disc and a release bearing.
There are different choices for your BMW clutch and flywheel setup depending on what your vehicle is used for.
Discussed below are SAC, performance clutches and the types of materials available for clutch discs.
CLUTCH / FLYWHEEL BOOKING
Different types of Clutches
These are commonly the choice for BMW owners who have modified their vehicles performance from factory specification such as with remapping or turbo upgrades.
Performance clutches are normally described as stage 1-4 clutches which relates roughly to the level of tuning the vehicle has undergone.
Paddle clutches, otherwise known as cerametallic clutches, allow the transmission of more torque before slip occurs.
They are made up of a metal and ceramic mix of components. The pressure plate has “paddles” and different amounts depending on the torque specifications.
Generally, the more paddles on the clutch the more smooth the clutch will feel, although these clutches were designed with performance in mind and they are hard to get used to for many drivers.
Self Adjusting Clutch
Most BMWs from around 2000 use a self-adjusting clutch.
They are designed to compensate for wear to the clutch disc by adjusting and increasing the life of the clutch as a result.
Special tools known as clutch-alignment tools are required for fitting this type of clutch and if this procedure is not followed correctly the clutch will be useless and not function correctly, if at all.
Clutch Disc Materials
Most BMWs will leave the factory with an organic clutch.
They are designed for ease of use and even uprated versions of the organic clutch allows for some slip.
Some clutches are also made from ceramic materials although these are heavier and increase wear on other components as a result.
Different types of Flywheels
There are several different types of flywheels to choose from. Your choice is partly dictated by the type of clutch you choose for your BMW alongside what your car is mainly used for.
If you need help deciding which flywheel is right for your vehicle, our trained technician will be happy to advise you.
This flywheel is made up of two metal plates, the primary and secondary mass, connected by dampening components between. The design aimed to reduce vibration and protect from torque reaction through the drivetrain.
These flywheels were commonly found in pre 1991 BMWs. By design, they aimed to last a vehicles lifetime, and they were resurfaced when replacement of the clutch was needed.
The E30 M20B25 engine commonly used a factory fitted single-mass flywheel.
These should be fine to use daily on the road although drivers should expect slightly more vibration than with a dual-mass flywheel. There will also be less stress on other engine components as it doesn’t weigh as much and requires less force to rotate.
These are only really considered for highly-tuned performance vehicles. They are not normally recommended for road use or daily driving.
They are very lightweight by design and improve the performance of the vehicle through greater torque delivery.
Signs of Clutch wear or fatigue
The most common sign of clutch wear is normally a high “biting point” where the driver needs to bring the pedal up further than usual to meet with the accelerator. Other common signs include unpleasant noises such as rattling, the clutch not engaging or not disengaging, clutch slip or trouble changing gear. If you have any of these issues it is time to have your BMW inspected as soon as possible to avoid repair costs rising.
Wear to other components
There are other components which make up the drivetrain of your BMW and of course these wear and require replacement over time. The clutch release bearing is normally replaced with the clutch assembly and you will more than likely receive a new one as part of a clutch kit. Failure can also occur to the master cylinder and slave cylinder. Hydraulic fluid also plays an important role in the functioning of the clutch. If the fluid is low this can cause difficulty operating the clutch pedal