Jamis Bicycle Owner's Manual - page 16
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C. Brakes
There are three general types of bicycle brakes: rim brakes, which operate by squeezing the wheel rim between two brake pads; disc brakes,
which operate by squeezing a hub-mounted disc between two brake pads; and internal hub brakes. All three can be operated by way of a
handlebar mounted lever. On some models of bicycle, the internal hub brake is operated by pedaling backwards. This is called a Coaster Brake
and is described in Appendix C.
WARNING:
1. Riding with improperly adjusted brakes, worn brake pads, or wheels on which the rim wear mark is visible is dangerous and
can result in serious injury or death.
2. Applying brakes too hard or too suddenly can lock up a wheel, which could cause you to lose control and fall. Sudden or excessive
application of the front brake may pitch the rider over the handlebars, which may result in serious injury or death.
3. Some bicycle brakes, such as disc brakes (fig. 11) and linear-pull brakes (fig. 12), are extremely powerful. Take extra care in
becoming familiar with these brakes and exercise particular care when using them.
4. Some bicycle brakes are equipped with a brake force modulator, a small, cylindrical device through which the brake control cable
runs and which is designed to provide a more progressive application of braking force. A modulator makes the initial brake lever force
more gentle, progressively increasing force until full force is achieved. If your bike is equipped with a brake force modulator, take extra
care in becoming familiar with its performance characteristics.
5. Disc brakes can get extremely hot with extended use. Be careful not to touch a disc brake until it has had plenty of time to cool.
6. See the brake manufacturer’s instructions for operation and care of your brakes, and for when brake pads must be replaced. If you
do not have the manufacturer’s instructions, see your dealer or contact the brake manufacturer.
7. If replacing worn or damaged parts, use only manufacturer-approved genuine replacement parts.
B. Seat post cam action clamp
Some bikes are equipped with a cam action seat post binder. The seat post cam action binder works exactly like the traditional wheel cam
action fastener (Section 4.A.2) While a cam action binder looks like a long bolt with a lever on one end and a nut on the other, the binder uses
an over-center cam action to firmly clamp the seat post (see fig. 8a).
WARNING: Riding with an improperly tightened seat post can allow the saddle to turn or move and cause you to lose control
and fall. Therefore:
1. Ask your dealer to help you make sure you know how to correctly clamp your seat post.
2. Understand and apply the correct technique for clamping your seat post.
3. Before you ride the bike, first check that the seat post is securely clamped.
Adjusting the seat post cam action mechanism
The action of the cam squeezes the seat collar around the seat post to hold the seat post securely in place. The amount of clamping force
is controlled by the tension adjusting nut. Turning the tension adjusting nut clockwise while keeping the cam lever from rotating increases
clamping force; turning it counterclockwise while keeping the cam lever from rotating reduces clamping force. Less than half a turn of the
tension adjusting nut can make the difference between safe and unsafe clamping force.
WARNING: The full force of the cam action is needed to clamp the seat post securely. Holding the nut with one hand and turning
the lever like a wing nut with the other hand until everything is as tight as you can get it will not clamp the seat post safely.
WARNING: If you can fully close the cam lever without wrapping your fingers around the seat post or a frame tube for leverage,
and the lever does not leave a clear imprint in the palm of your hand, the tension is insufficient. Open the lever; turn the tension
adjusting nut clockwise a quarter turn; then try again.