FAQ’s PLUS TECHNICAL GLOSSARY
Clutch FAQ
Q 1 Why choose a “Super Clutch” Motor Sport clutch ?
A. Because of our Racing Specialisation ! This means everything from top quality product range and availability to the best supporting technical advice and service.
Q 2 What performance advantage can a Super Clutch Racing clutch give ?
A. Super Clutch Motor Sport clutches are intended for all forms of Racing & Rallying. They are optimised for compact dimensions with associated low weight/inertia to enable improved engine response and quicker acceleration due to reduced flywheel effect. Generally, a more effective improvement than searching for the ultimate in engine power.
Q 3 I understand the benefits of reducing the clutch size, but what is the down-side?
A. Greater clutch control skill is required with smaller clutches due to reduced flywheel effect. Thermal capacity reduces in proportion to the size/volume and number of clutch plates leaving less reserve. These compromises are worth it for the associated improved engine response and consequent improvements in lap/stage times.
Q 4 How about an up-rated standard clutch instead of a purpose made Motor Sport clutch?
A Motor Sport clutches take over at the point where an up-rated original equipment type clutch can no longer do the job, and can be tailored to match power/torque and duty level. An up-rated original equipment type clutch is only appropriate for limited engine output or duty level increases for applications not requiring weight saving or improved capacity.
Q 5 What is a “Paddle” type clutch disc?
A. Simple system superseded by modern high thermal capacity fully bonded 3600 contact systems. Originally to upgrade standard clutches for higher temperatures. Can create rapid wear and give rough clutch engagement. Usually resembling a flattened three blade propeller with small pucks of metal friction material riveted to a clutch disc centre.
Q 6 Why all this talk about heat and thermal performance?
A It is the critical but often forgotten part of the clutch selection equation! Clutches are like brakes ….. the cooler they run, the longer they last and the nicer they are to drive.
Q 7 When is a Carbon clutch appropriate?
A Not often. Usually organic or metallic is best. Carbon may survive higher operating temperatures and offers the ultimate weight/inertia reduction. Rapid and expensive wear may occur unless used in its optimum load/temperature zone.
Q 8 How long will a Motor Sport clutch last?
A. Life-span is just one attribute of any clutch and is influenced by many factors including thermal input and driver style. A balance point must be chosen between durability, performance characteristics, cost etc to meet individual requirements.
Q 9 What are the basic requirements for installing a Motor Sport clutch?
A. A specific flywheel mounting pattern & clutch release bearing is required. Conversion assistance, and parts are available, but most Race/Rally cars will already be configured to suit.
Q 10 What is the best Motor Sport clutch for my application?
A. Only the customer can select the most appropriate match with their requirements. We offer comprehensive choice, plus supporting information, data and motor sport experience
Clutch Release Bearing FAQ
The clutch release bearing is the part at the end of the system under your left foot that releases the clutch …… it has a particularly hard life in motor sport applications.
It makes sense to replace bearings as a routine service item.
We have searched to bring you the best quality release bearings and manufactured a special bearing to our requirements. We stock many different bearings in metric and imperial sizes, including hard-to-get types such as Saab and inner rotating versions.
Improvements in pedal feel and control, plus reductions in load can be obtained by using the smallest possible release bearing size.
The best clutch release systems have a direct acting “hydraulic release bearing” – essentially a hydraulic cylinder that fits around the gearbox input shaft. They improve efficiency, save weight, and simplify the system, often being easier to fit particularly on full race vehicles.
We have two distinct types of hydraulic clutch release system:-
1. Fixed – mounts rigidly to the bellhousing or via an adapter to the front of the gearbox.
2. Floating – slides over the guide tube on the front of the gearbox where the original standard mechanical bearing used to go.
There’s nothing wrong with mechanical systems – sometimes they are easier to adapt onto a vehicle that already has a cable – if you chose this option we have a range of bearings and carriers.
Alternatively you may purchase just the bearing by itself – we have many types and sizes.
Most motor sport clutches require relatively short release bearing travel to release, and so increasing the hydraulic ratio or the pedal ratio often improves clutch control and reduces pedal effort.
Remember that clutch release bearing travel must be controlled by a stop under the clutch pedal.
FAQ’s
Q. Does the clutch release bearing run at the same speed as the clutch?
A. No. They are intended for intermittent use during clutch changes, and can burn out if the driver rides the clutch pedal. This means that the clutch actuation system must be set so there is a clearance between the bearing and the clutch during normal running.
Q. What is special about motor sport clutch release bearings?
A. Motor sport release bearings are usually all steel construction to withstand high rotational speeds and heavy loads. Road car clutches usually have plastic and rubber parts for cost reasons, and because they are not so highly loaded.
Q. What type of clutch release bearing is required?
A. Most motor sport clutches have a flat spring, and therefore require a release bearing with a radius contact face to roll against the spring as the clutch is operated.
Technical Glossary
Clutch – a device to connect/disconnect the engine from the transmission. Required to match road speed to engine speed, and facilitate gear-changes. Especially hard worked in motor sport cars which for performance reasons, have lightweight low inertia clutches and flywheels, high first gears, and generally arduous thermal operating conditions.
Clutch Diaphragm Spring – the component that provides the clamping load to the clutch internal parts so that the clutch does not slip when torque is applied. A diaphragm spring is essentially a flat and therefore compact version of a conventional coil spring. It can exert tremendous power over a short distance. Some motor-cycle clutches have coil springs, but generally coil springs have been superseded by diaphragm springs.
Clutch Disc – or clutch plate. The component with the friction material on it. Mounted to the transmission input shaft via a spline system.
Clutch Intermediate plate – the component separating the clutch discs on multi-disc clutches. Provides additional friction surfaces to multiply the torque capacity of the clutch.
Clutch Pressure plate – the component underneath the clutch cover that applies the clamping load generated by the clutch diaphragm spring to the clutch discs and floater plates.
Clutch Release Bearing -- operates against the clutch spring in order to connect/disconnect the engine from the transmission. Controlled by the driver operating the clutch pedal.
Hydraulic Release Bearing – concentric or co-axial hydraulic slave cylinder. A very efficient method of actuating the clutch. Reduces driver pedal effort, increases fine control and consistency. Convenient, space effective and generally considered the most reliable and system for motor sport.
Inertia – the tendency of a rotating object, such as a clutch and flywheel assembly, to resist changes in speed. Power is required to overcome this resistance to change speed. Low inertia components accelerate/decelerate more quickly than high inertia components resulting in quicker engine response and improved performance.
Pilot bearing – or bush. Locates in the end of the crank to support and centralise the transmission input shaft.
Torque – the amount of twisting power provided by the engine. The clutch must be able to transmit the torque generated by the engine, plus an amount of inertia torque, without slipping.
We are continually adding to our motor sport product range. If the product or information is not shown, please contact –
Super Clutch
Telephone +44 (0)1926 812 136
Fax +44 (0)1926 815 410
eMail sales@superclutch.com