Hill climbing and negotiating rough trails are two of the most exciting things that we all love to do with our off road trucks. We can't wait to sink our money into bigger, knobbier tires; lifted suspensions; aftermarket bumpers; and other important equipment designed to give our trucks more power and ability over difficult terrain.
Despite these different upgrades, off roaders need to understand what RTI - ramp travel index - is and how it relates to what you can actually do with your prized rock climber. Learn to maximize your RTI and you’ll get much better performance over the roughest rocks and trails.
What Is RTI?
Ramp Travel Index is a calculation of vehicle flexibility and expected performance while traveling over obstacles based on the function of many different parts. RTI takes into account things like frame flexibility, suspension length and strength, and tire size and pressure, all of which work together to create balance and traction.
The RTI Test
If you’ve ever wondered what people at off roading shows were doing by driving one wheel of their trucks up those ramps, they were measuring their vehicle’s RTI. Ramp Travel Index tests duplicate conditions that could be encountered on the trail, giving Ford or Chevy truck owners a chance to see how their vehicles will respond at differing angles.
The goal is to climb the steepest incline with one tire without lifting any of the other wheels off the ground. This is only happen when trucks have the right combination of wheelbase, tire inflation, and suspension length. The higher the angle that the truck can handle without losing ground contact with any other tires, the more flexible that truck is assumed to be. RTI can also be measured without a ramp using either a pallet and forklift or even a floor jack.
Why Does RTI Matter?
A higher RTI rating usually means a truck can climb larger obstacles and effectively drive over rougher terrain without getting stuck. The reason for this is because when all four wheels are still on the ground, the truck has full traction to climb over those obstacles. Once the size of the obstacle increases to the point that climbing with a front tire causes another tire to come off the ground, essential traction is lost, reducing the ability to get over these obstacles.
Factoring in RTI can be essential in planning vehicle upgrades as well as for planning safe trail driving by allowing drivers to understand what their trucks can do. In other words, knowing your RTI can keep you from getting stuck on the trail and need to be winched out or worse yet, being put in a compromisng situation that could be unsafe.
How to Improve RTI
Off roaders who want maximum rock climbing and obstacle clearing capability must increase RTI. A well-known trick than will help increase traction on rougher terrain is to air down tires to as much as half the recommended PSI. Be sure to consider ahead of time things like beadlocks and being able to air back up.
Other ways to improve RTI is to disconnect sway bars and grease leaf springs. Just be sure to reconnect them before going back onto the road. A longer or more flexible suspension may also improve RTI.
The next time you bring your truck to an off road event and there’s a ramp present, go ahead and give it a shot. It’s more than just how high you can go. Smart truck owners will use the opportunity to learn about their vehicles, if their investment in all those aftermarket parts really work together, and whether something different is needed for good obstacle clearance. Most importantly, learn your truck’s RTI to keep yourself safe while reducing the damage your truck will sustain while you’re trying out newer, tougher trails!