Suicide clutch

A chopper with a hand shifter

A Harley motorcycle with an aftermarket "jockey shifter".

The terms "suicide clutch" and "suicide shifter" (or "jockey shifter") refer to a motorcycle foot-operated clutch and hand-shifter to change gears,^{[1][2][3][4][5]} found on early designs from around the turn of the 20th Century to the 1940s or 50s, and reappearing on modern retro styled custom motorcycles and choppers. Modern motorcycles do not require removing a hand from the handlebars to operate the clutch or to shift gears, using only the fingers for the clutch and the toes of one foot to select gears.^[6] In contrast, the fanciful slang "suicide" was applied to designs where the rider removes one hand to change gears, or cannot put both feet on the ground while using a foot clutch to disengage the transmission. Sometimes the shifter is referred to as a "jockey shifter" while the foot clutch is called a "suicide clutch".

More technically, "suicide clutch" can refer to clutch controls lacking a detent on the foot clutch, which would otherwise allow the rider to lock the clutch in the disengaged position. Early foot-clutch motorcycles, such as those from Harley-Davidson and Indian, allowed the rider to lock the clutch foot pedal, so they could place both feet on the ground when stopped. If this device was disabled, or a custom foot clutch was installed that had no detent, it was referred to as a "suicide clutch" because stopping the motorcycle in-gear required the rider to keep his foot on the pedal. Should he lose his balance and put the left foot down, the motorcycle could lurch forward into cross traffic.^{[citation needed]}

The suicide clutch is sometimes called a suicide shifter. The suicide clutch is a foot-operated clutch that is mounted on the left side of the motorcycle's forward foot controls.^[7] The suicide-clutch moniker has derived from difficulties in operating this form of clutch and shifter. On a motorcycle equipped with a conventional hand clutch and foot shifter, the rider places the left foot on the ground when stopped and holds the motorcycle in place with pressure on the rear brake pedal with the right foot, while engaging the clutch with the left hand. On a motorcycle equipped with a suicide clutch, the clutch is held in with the left foot, requiring the right foot to hold the bike in place, with the right hand applying pressure to the front brake. Early Harley Davidson foot clutches used a spring to return the clutch pedal to the disengaged position and used a friction disc to allow the rider to adjust the sensitivity of the return. Often riders removed the spring to keep the clutch pedal from returning to the disengaged position while riding. While this spring removal allowed for the clutch to stay engaged better, it also removed the safety feature of the clutch pedal holding itself in the disengaged position. With the pedal not returning to its natural disengaged position, the rider must either shift into neutral or hold the clutch pedal with the left foot when coming to a stop. Early Harley Davidson racers removed the clutch return spring to ensure the clutch stayed in the engaged position throughout the race. This practice soon caught on with other riders. The term "suicide clutch" was coined by those who could not operate the foot clutch proficiently enough to ride a tank shift (or hand shift) motorcycle in normal traffic.

Types of shifters

Old-style tank shift.

Regular clutch hand Shifter - This is where the shifter is a regular knob and involves the semi-complex task of two-handed shifting. One hand is used to press the clutch lever on the handlebars and the second hand is used to shift gears.

Clutched Shifter - This shifter has a clutch lever on it allowing one-handed shifting. This design allows the left foot to be free.

Usage

Suicide clutches were common on mid-20th century Harley-Davidson motorcycles and many custom bikes today still employ this system. Harley-Davidson introduced the hand clutch, with uncharacteristically little fanfare, on the 1952 Panhead.^[8]

Trikes based on cars such as the Volkswagen Type 1 usually keep the original shifter.^{[citation needed]}

ABC motorcycle with hand shifter at the Cité de l'Automobile museum.

1919 Harley-Davidson Model W Sport Twin with hand shifter at The Art of the Motorcycle, Memphis.

The jockey shifter is a gear shifting device used on motorcycles before the use of a foot-operated shift lever. A jockey shifter, also known as a slap shifter, gets its name from the location of the motorcycle rider's hand when shifting gears. It is under his seat like the position of a jockey's hand while using his riding crop on his horse. This hand shifter lever is directly mounted to the transmission and is just long enough to clear the primary drive cover or belt drive. A motorcycle equipped with this type of shifter requires the use of a foot clutch. The foot clutch comes in one of two configurations; either a rocker foot clutch, which was stock on many early motorcycles, or a suicide foot clutch, which was never available on production motorcycles but was manufactured by daring motorcycle enthusiasts. The rocker foot clutch is easier to use than the suicide foot clutch because it can be rocked into a position where the clutch is either engaged or disengaged - leaving the rider's foot free to be put down, at a stop, to steady the motorcycle. Sometimes a tank shifter is referred to as a jockey shifter, but this is incorrect due to the rider's hand position being in front of him, not behind him like for a horse jockey. A tank shifter is also connected to the transmission with linkage, which jockey shifters do not use. The earliest known use of a foot clutch and hand shifter, on motorcycles, was with the first multi-geared transmission on the 1915 Harley Davidson.^[9] It is a mechanical linkage that is typically mounted to the left side of the motorbike's fuel tank and is held in place by a slotted piece of metal welded to the frame or the tank.^[7] Through a series of linkages, it is connected to the transmission shift selection lever. In terms comparable to a motorcycle of current construction, it is simply a way to relocate the shift lever from the front foot controls to the side of the gas tank. Early motorcycle customizers who were trying to reduce their motorcycle's weight so as to increase its power-to-weight ratio would sometimes replace their stock rocker foot clutch with a hand fabricated suicide foot clutch, and remove the tank shifter's linkage and instead attach a shifter arm directly to the transmission. This reduced weight not only made the bike accelerate better, but also gave the rider bragging rights of riding a motorcycle which required more skill to operate.

Notes

References