RTI (Ramp Travel Index) Calculator

Introduction

The RTI (Ramp Travel Index) Calculator is a measure of a vehicle's suspension flexibility and articulation, a benchmark for off-road performance. The RTI score represents the ability to keep all wheels on the ground for maximum traction while one wheel climbs a ramp. A higher score means the vehicle can better navigate irregular terrain without wheels lifting off, which is directly linked to off-road traversal capability.

How It Works

The formula for RTI is '(Distance Traveled Along Ramp / Wheelbase) x 1000.' It's typically measured on a 20-degree ramp, tracking the distance until one of the rear wheels loses contact with the ground. The calculator contrasts the traveled distance with the wheelbase to derive the score and assigns professional ratings like 'Standard SUV' (600), 'Excellent Modified' (800), or 'Extreme Off-Road Machine' (1000+).

Usage Scenarios

• After completing suspension tuning (lift kits, long-arm systems, etc.), record the improvement in flexibility with an objective figure to verify the quality of the modification.
• Compare RTI scores with and without sway bar disconnects to see the data-backed impact on traction during actual off-road use.
• Before entering an off-road event or competition, pre-calculate your official RTI score to determine your vehicle's class and find the optimal suspension settings.

In-Depth Guide

RTI = (distance the vehicle travels up the ramp / wheelbase) × 1000, measured until any tire lifts off. Worked example: a vehicle with a 2,500 mm wheelbase that drives 1,500 mm up the ramp scores (1500 / 2500) × 1000 = 600. To compare scores fairly, the ramp angle must match — the common standards are 20° and the stricter 23° ramp, and a score quoted on a 23° ramp is not comparable to one from a 20° ramp.

Because wheelbase is in the denominator, a longer-wheelbase truck is penalized for the same physical articulation; this is why short-wheelbase rigs post higher RTI numbers even with equal suspension travel. A common mistake is treating RTI as a pure flexibility metric — it actually measures articulation relative to vehicle length, so two vehicles with identical droop can score very differently.

Scores above 500 indicate good articulation, with modified trail rigs reaching 800+ and extreme builds exceeding 1000 (the vehicle travels farther than its own wheelbase up the ramp). Disconnecting sway bars, fitting longer shocks, and softer springs all raise the score, but excessive articulation can reduce on-road stability, so builders balance RTI against handling rather than chasing the highest possible number.