First the ramp. In most cases the ramp is on a 20 degree angle. Some events measure the extremely flexible vehicles with a ramp of greater angle like the 23 degree ramp. The vehicle attempts to climb the ramp as high as possible without lifting a wheel off the ground. The distance the vehicle can travel up the ramp without losing contact with the ground is measured from the leading edge of the ramp to the center of the hub on the ramp. That number is then divided by the vehicles wheelbase (the distance between the vehicles centerline of the front axle and the centerline of the rear axle) and then multiplied by 1000 to calculate the average.
For instance, if a vehicle with a wheelbase of 94 inches travels 62 inches up the 20 degree ramp then the RTI would be calculated as: 62" divided by 94" x 1000 resulting in a score of 659. This method of multiplying by the vehicles wheelbase allows one vehicle to compete with another vehicle like a CJ-5 to an F-250 Crew Cab on the same ramp test
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