SKU: FAP-S040-ATT
MPN: FAP-S040
STM Slipper Clutches for Street Motorcycles / Sport Bikes

STM Slipper Clutches kit assembly uses original Friction Plates, Drive Plates and basket.

The slipper clutch that started it all! STM Slipper Clutches are beautifully fabricated in anodized aluminum alloy and titanium. Selected for use by Ducati's World Superbike team, still the best choice for higher horsepower machines. These are the EXACT Same STM Clutches that are used by Ben Bostrom, Noriuki Haga, Franki Chilli, and Many other Top Road Racers World Wide.

ALL STM Clutch is made IN HOUSE at the Italy Shop, with the highest tollerance and quality control. Each part is stamped with a Part number, and Serial number to keep quality control and records of all part made. This insures what you receive is only the best, everytime. STM Slipper Clutches are Now available for most Modern Sport Bikes.

What Make STM so Good?

How STM Slipper Clutch Work:

Ball & Ramp Actuation: STM was instrumental in developing the Ball & Ramp Actuation technology. In order for a slipper clutch to work, there must be a reduction in friction in the clutch pack. This is typically accomplished by using a drum and hub which are independent of one another. When these two components rub together during slipper clutch operation, friction, heat & wear are greatly increased. STM solves this problem by placing ball bearings between the hub & drum. The result is not only much smoother slipper clutch operation but a significant reduction in friction and heat. This all leads to increased clutch durability and component life.

PEP - Progressive Engagement Plate: The progressive engagement plate is a titanium nitrated plate that allows the clutch pack to float or shift slightly when the clutch closes down after the slipper aspect has been activated. This provides for smoother clutch closure and decreases the abruptness a rider may feel when the clutch begins to lock up again.

Diaphragm Springs: Diaphragm Springs have 3 distinct advantages over the traditional helicoil springs used in clutches. #1. Digressive Lever Engagement helicoil springs are progressive, meaning the more you compress the spring, the more difficult it becomes to compress. With diaphragm springs the opposite is true. A diaphragm spring progressively becomes harder to compress through 3/4 of the travel, however the last 1/4 of travel actually becomes easier. What this means to a rider is that as the clutch lever travels towards the handlebar, the lever pull gets easier for the last 1/4 of travel as the lever approaches the bar. The result is when a bike is on the starting line, you do not have to give as much throttle to effectively launch the bike off the line. #2. Less Drag than Helicoil Springs when helicoil springs are installed in a clutch they are slightly compressed meaning they are dragging. Diaphragm springs are at rest in the STM clutch and therefore have no drag on them. #3. More consistent and even pressure on clutch pack which eliminates "hot spots" in the pack. This leads to better clutch lock-up and increased clutch pack life.

STM Clutches are fully adjustable: An aspect that sets STM slipper clutches apart from all others is their ability to be adjusted & tuned in both the primary & secondary. The primary spring controls the pressure on the clutch pack during lock up. STM diaphragm primary springs are weighted in Kilograms and offered in 10Kg increments. There are several different weights to choose from (sold individually). Through the use of varying weights, the engine builder can adjust the amount of pressure on the clutch pack to compensate for any engine modifications and subsequent increases in horsepower. The secondary spring is what controls the amount of engine brake. The lighter the secondary spring, the less engine brake; the heavier the secondary spring, the more engine brake. The 85mm diaphragm secondary springs are weighted in Kilograms and offered in 10Kg increments. There are 6 different weights to choose from (sold individually). Through the use of varying weights, the rider can adjust the amount of engine brake desired to fit their individual riding style.

FLS - Forced Lubrication System: The 'FLS' Forced Lubrication System is unique to STM clutches. The system is a complex network of oil passages that actually increases the amount of engine oil flowing through the wet clutch. The FLS reduces running temperatures and increases cleaner conditions inside the clutch which increases the performance and longevity of the clutch components and pack.