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riding at high speeds is the goal of the rider, like in racing competition, and especially in downhill races. For

the average biker the suspension system won’t become useful until the system has been improved to : 1.

Minimize geometrical changes; 2. Design the suspension in such a way that it can be turned on or off as

circumstances require; 3. Reduce weight.

Rear-Wheel Suspension

After the front-wheel suspension systems gained acceptance, it was only a matter of time before

engineers designed a suspension system for the rear-wheel. This was considered to be an ambitious

undertaking, because it meant jeopardizing the stability of the rear frame, a vital part of the frame structure.

At the end of 1990, Cannondale, Offroad, and Gary Fisher introduced the first rear-wheel suspension.

Cannondale and Offroad used similar systems. They both have elevated chain stays providing lateral sway,

with the pivot point located in the front of the seat tube. Cannondale uses an oil-pressure suspension, the

Offroad rear frame is protected against shocks by plastic devices. These suspension systems are well made

and designed, but they also contribute to some problems: Stiff wishbone construction at the rear frame

lessens lateral stability; interference with the important geometry of the rear frame by adding shock

absorbers will also cause considerable loss to the bike’s lateral stability, changing the ride of the bike. Gary

Fisher installed plastic devices to absorb shocks. They’re located behind the bottom bracket. Chain tension,

however, makes the rear frame more rigid (due to the lowered seat-stay position); traction is not affected.

Rear-wheel suspension is great for riding downhill, because potholes are smoothed out, and tires

are protected from severe punishment. However, uphill riding can be an ordeal when the rear of the frame

bounces with every pedal stroke. This can drain the energy from the rider quite rapidly. A bike equipped

with rear-suspension is also heavier. At this time no satisfactory solution has been found; the many

different versions are all still in the experimental stages. This technology is still recent and still has room for

improvement. A rear-wheel suspension that is standard to most bikes has not yet been found.

Gears

Shifting and drivetrain have undergone enormous evolutions. Today four different methods of

shifting gears are available: single shift, double shift, rotation-grip, and grip shift. All four of the systems are

different. The one thing that they all have in common is that they are all indexed. The functions of the front

and rear derailleurs have reached high standards, technologically and functionally. In combination with

numerous gear positions this is (at this time ) the most perfect gear shifting system. The only disadvantage

is that it needs frequent attention and adjustment.

To shift gears smoothly and silently before the invention of the indexed system was truly difficult.

It was a process of slow learning, and only professionals knew how to do it properly. The indexed system,

however, made it possible for even a novice rider to master the art of shifting gears properly and with ease.

The indexed system has a built-in mechanism that enables the derailleur to move in such a way that the

chain rests securely on the chain ring as well as on the sprockets.

Single Shifter

Today, as in the past, the single shifter is the one that most bikers prefer. It is close to the

handgrip, and top mounted, this one is the lightest (51/4 oz or 150 g) and reaches every sprocket within a turn

of 90.. This system also makes it possible to disengage the indexed system, so that in case of difficulties,

the gears and derailleur can be used manually, using the friction system. The only disadvantage is that the

position of the lever isn’t ergonomically perfect. The thumb has to move up above the handlebars each time

the gears have to be shifted. However, the single shifter system is preferred for all racing bikes.

Double Shifter

For ergonomic reasons, a few of the professional mountain bike racers, moved the shifter below

the handlebars. The lever worked well of the biker pushed the lever away from himself. It was pulling it

back that was the problem. To solve this problem the double shifter was introduced in 1989. The shifter

was split into two separate levers. The lower lever moved the chain to a larger sprocket and the upper lever

moved the chain to a smaller sprocket. The whole procedure became more complicated; instead of one

movement in two directions, using one lever; now two movements, using two levers in two directions,, was

necessary. To shift gears it was necessary, even for trained bikers, to learn the whole new procedure.

despite the improved position of the shifter the double shifter system has a disadvantage; although by using

the lower lever the largest sprocket or chain ring can be reached, to shift to a smaller sprocket (to the right),

it’s necessary to push the lever six or seven times, causing a slight slowdown. Although it is a minor

inconvenience for the recreational biker, it is a concern for mountain bike racers.

Rotation-Grip Shifter

Handle bars with a diameter of 7/8″ (22.2 and 22.7 mm) are equipped with a 61/4″ (16 cm) long

rotation grip with two or three mechanisms inside. The springs, activated by pressure, cause a mechanism

either to tighten or to loosen the gear cable.

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