FRONT WHEEL DRAG
When the motorcycle and brake system is cooling, it is often seen on hard brake circuits that the front wheel starts to drag more and more. When completely cooled to ambient temperature it is sometimes seen that the front wheel can be difficult to spin. Before the bike goes out on the track again, it is recom- mended to “zero” the brake system by pressing the brake pads and thus the pistons back, by moving the floating discs and pads in/out – until the wheel is turning completely free. Then pump the brake lever until there is again contact between the brake pads and disc, and the brake lever feels firm/hard.
A known issue with the use of sintered brake pads for racing is that the front wheel/discs drag in the calipers. This problem is generated by the sinter material’s good heat transfer properties, which ensures that the heat generated between the brake disc and the brake pad is transferred directly through the friction material to the steel backing plate, after which the heat is distributed to the caliper pistons, brake fluid and the caliper body. Although brake calipers for race use are one-piece monoblocs the caliper body will expand and flex during use at high temperatures and mechanical load from brake pressure. When the bike is raced on the track and the braking system is hot and constantly exposed to various brake pressures, movement and vibrations from the bike and suspension, there is usually no front wheel/discs drag – this can be inspected quickly when the bike returns to the pit lane by lifting the front wheel of the ground and check that the wheel spins freely.
Always a good procedure to “zero” the brake system before going out on track for a new session.
WARPED BRAKE PADS
On circuits (ie GP circuit RedBull Ring) with many subsequent sectors of long hard braking’s from high speed, seeing high temperature and mechanical load to the brake pads. Mechanical stress and tension can occur between the steel backing plate and the friction material which can cause a deformation of the brake pad. Extensive testing within GP and World Superbike of special samples with thicker backing plates or backing plates with special strength properties, special hardening or annealing of backing plate steel has not improved the properties to obtain the perfect and ideal overall mechanical stability of the brake pad.
Experience from 24-hour World Endurance on hard braking LeMans, has shown that thinner steel backplates with more friction material are more resistant to internal mechanical stress and thus backplate deflection. SBS R&D is working intensively on the ideal solution especially for our DS Dual Sinter brake pads to be used for these extreme hard braking circuits and long-distance races.
19
19
HI-TECH BRAKE SOLUTIONS MADE IN EUROPE
Made with FlippingBook. PDF to flipbook with ease