Main Brakes

Solar cars must have a dual, balanced braking system so that if one system should fail, the solar car can still

be stopped. The two systems must be operationally independent and must operate from a single pedal.

The braking system can be front/rear or redundant front. Left/right redundancy is not permitted.

Hydraulic systems must have separate master cylinders. Regenerative brakes may not be considered as

one of the braking systems.

7.5.A Brake Pads:

Each brake pad used in the braking systems must have a contact area

with the brake disk that is greater than 600mm^2, and the pad must have full contact with the brake

rotor. Pads must initially be at least 6mm thick including the backing plate when installed on the car.

7.5.B Braking Performance:

Solar cars must be able to repeatedly stop from speeds of 50km/h or greater, with an average deceleration, on level wetted pavement, exceeding 4.72 m/s^2. Performance shall be demonstrated with mechanical braking only.

7.5.C Brake Lines/Cables:

The brake lines (hydraulic or cable) shall be appropriately sized and constructed such that they have significant capacity beyond the pressure and/or loads that will occur under the worst-case driving conditions.

7.5.D Placement of Brake Pedal:

The brake pedal for the dual braking system shall be placed under the driver's right foot.

7.5.E Clearance between Pedals:

If the team elects to have foot operated brake and accelerator pedals the team must demonstrate adequate clearance and arrangement that will allow for quick and easy transition of the foot from one pedal to the other. Refer to Reg. 5.9.A for placement of the accelerator pedal if equipped.

7.5.F Hand Activated Brakes:

Hand activated brakes are permissible if the driver can turn the steering wheel lock-to-lock without removing or repositioning either hand from the steering wheel.

7.5.G Cars with Mechanical Rear Brake

7.5.G.1 Performance:

Cars with mechanical rear brakes as one of their primary brake systems shall be able to demonstrate that the rear brake can hold the car in place (front wheels elevated off the ground) on dry pavement under a forward pull equal to 15% of the cars weight in driving configuration with properly ballasted driver in place.

7.5.G.2 Volume Limiting Valve-System:

Cars with mechanical rear brakes with proportioning values will require a means to lock-out the proportioning value setting. The proportioning value shall be positioned away from the drivers reach.

***Braking systems for solar cars should be designed in accordance with standard automotive engineering practice. In general, bicycle type brakes are deemed to be too fragile for this kind of application and will not pass scrutineering. This includes mountain bike type disc brakes. While such brakes may have enough stopping power to slow down a solar car, over long periods of application descending hills common in the ASC competition, they do not have appropriate levels of brake energy dissipation. Larger pads with more contact area can help ensure that vehicle braking systems are designed to dissipate heat to prevent failures involving boiling brake fluid, disc warpping, and loss of braking force. Vehicles that do not heed these recommendations may not pass scrutineering or be allowed to compete.