Clutch Disk Tech

Marcels - A clutch disk with marcel construction has the friction material of both sides backed by thin metal plates. Between these two plates are thin bowed pieces of steel (marcels), which act as springs when the disk is sandwiched between the flywheel and pressure plate. When the clutch pedal is let out, the marcels are flattened, and gradual engagement of the clutch is achieved. Marcels are more critical than a sprung hub in providing chatter-free clutch operation. Disks without marcels usually have poor drivability, unless the friction material has some compressibility (as sintered iron does). Over time, the marcels in a disk can lose their springiness and flatten out, increasing the likelihood of chatter.

Organic Friction Material - All Mustangs came stock with organic friction material because of its excellent drivability characteristics. McLeod uses a unique friction compound in their organic disks. They have a higher heat capacity than both stock and other aftermarket organic disks. This is a good choice for most Mustangs used on the street, and even for racing. This material should be sufficient for 95% of Mustang owners with typical street-legal bolt on parts. The McLeod organic disks that we offer are all constructed with marcels.

Kevlar Friction Material - While this material typically has a lower coefficient of friction than organic materials at room temperature, it's coefficient of friction increases with elevated temperature. This means that as a Kevlar disk is heated during hard use, its torque capacity will increase, whereas an organic compound disk will lose torque capacity when its temperature is increased. Another advantage of Kevlar is its durability and resistance to wear. It will not burn as easily as organic compounds when slipped excessively. Burning causes permanent damage to the disc and a reduction in the coefficient of friction. The wear characteristics of Kevlar are significantly better than organic materials, making Kevlar a good choice for racing applications. The downside to Kevlar disks is that they have a high propensity to chatter when slipped. This makes them a poor choice for daily driven street cars, and weekend-only cars that are driven in stop-and-go traffic. Even though many other companies try to sell Kevlar clutch systems to street car owners, Maximum Motorsports wants to provide you with as much information as possible, and we do not recommend Kevlar clutches for extensive street driving. The Kevlar/organic McLeod disks that we list are all constructed with marcels, to reduce chatter as much as possible.