Choose an option below to learn how the RTI score is calculated
Explain it like I'm 5
Think of the RTI score like a test to see how well a car can climb over big bumps or hills without lifting its wheels off the ground. It’s like a game where we drive the car up a sloped ramp until one of the wheels just starts to lift off. We then measure how far the car went up the ramp. The RTI score is like a special score that tells us how good the car is at this game. It's calculated by comparing how far the car went up the ramp to how long the car is from front to back (that's the wheelbase), and then we multiply this by a special number (1000) to make the score easy to understand. Cars with a higher score are really good at climbing over bumps without losing touch with the ground, which is super important for off-road driving.
Technical Formula
The RTI (Ramp Travel Index) score is a quantitative assessment of a vehicle's axle articulation. This measure is pivotal in the realm of off-road performance, providing an empirical gauge of a vehicle's ability to maintain contact with the ground on uneven terrain. The calculation commences by driving the vehicle up a ramp at a specified angle until one wheel loses contact with the ground, marking the critical point of articulation. The RTI score is computed using the formula:
(Distance Travelled Up The Ramp/Wheelbase)×1000.
This formula ensures a normalized score that allows for cross-vehicle comparisons, irrespective of variations in wheelbase lengths. The resultant RTI score is inversely proportional to the ramp angle – a lower ramp angle typically yields a higher RTI score, signifying superior suspension flexibility.
Super Nerdy Calculations
The mathematical foundation for converting RTI scores between different ramp angles hinges on principles of trigonometry and the constant nature of the suspension's articulation point. The initial step involves determining the vertical height at which a wheel lifts off the ground when a vehicle ascends a ramp at a known angle. This vertical height remains constant regardless of the ramp angle and is a key to the conversion process.
Given an original RTI score (calculated at a specific ramp angle), we first decode this score to find the vertical height of articulation. The RTI score is defined as (Distance Travelled Up The Ramp/Wheelbase)×1000. By rearranging this formula, we can express the distance travelled up the ramp as (RTI Score×Wheelbase)/1000. Applying trigonometric principles, this distance up the ramp can be related to the vertical height using the sine function: Height=Distance Travelled×sin(Ramp Angle).
To convert this score to a different ramp angle, we maintain the constant vertical height and apply it to the new angle. By rearranging the sine function, we find the new distance travelled up the ramp as New Distance=Height/sin(New Ramp Angle). Subsequently, the new RTI score is recalculated using the original formula with the new distance travelled. This process underscores the fundamental relationship between the ramp angle and the vehicle's articulation, emphasizing the angle's impact on the vehicle's perceived suspension capability.This meticulous calculation allows for an apples-to-apples comparison of vehicle suspension performance across various ramp angles, providing a robust tool for enthusiasts and engineers alike in assessing and benchmarking off-road vehicle capabilities.