2014 Acura MDX: Ramp Travel Index
February 18, 2014
When the term was first coined, off-road capability was assumed to be the primary sport alluded to by the leading "S" in the term SUV. One of the primary predictors of off-road prowess is maximum suspension articulation, and we can readily measure that with a quick trip up our 20-degree RTI ramp to measure Ramp Travel Index.
Because it is SUV-shaped and has all-wheel drive, our 2014 Acura MDX recently underwent this simple procedure.
And the MDX set a record, of sorts, for Worst RTI Score (So Far) with 249 points.
This shouldn't be all that surprising, because the MDX's Super-Handling All-Wheel Drive system, known by the SH-AWD acronym, is more about on-road handling in all weather conditions.
The system helps with dry cornering and is positively expert in snowy and wet-road environments. This RTI score tells us that actual off-roading was never much of a design consideration when the suspension was being conceived, though we suppose gravel roads of reasonable condition are just fine.
During the measurement the flexible rubber extension attached to the Acura's front spoiler came into hard contact with the ramp's cheese-grater surface, which does not bode well for approach angle, another crucial off-road trait.
In case you're wondering, RTI is determined by driving the vehicle up a 20-degree ramp until the left-rear wheel lifts juuuust off the pavement, usually amid a flurry of wheelspin. That distance is then compared to the vehicle's wheelbase, and the result is multiplied by 1,000 to get a three digit RTI result. Get both left-side tires to touch the ramp and the score is 1,000.
Some folks prefer to multiply the 20-degree ramp travel distance by 100 and express the result as a percentage of wheelbase. Increasingly, I count myself among them.
Our Acura went 27.6 inches up the ramp, compared to a wheelbase listed as 111.0 inches. Divide one by the other and multiply by your preferred factor and you get either 249 RTI points or 24.9 percent.
This relives the Nissan Juke of worst-score status (257 / 25.7%) and it is knocking on the door of 100 points worse than the Mazda CX-5, our leading crossover with a score of 334 RTI points or 33.4 percent.
Even among crossovers, it seems clear the MDX was never intended for off-road travel.
For perspective, our departed 2012 Jeep Wrangler left the showroom able to earn 561 points, and we were able to raise that to 908, a climb of 90.8% of its own stubby wheelbase, with the mods we added during its time with us.
Dan Edmunds, Director of Vehicle Testing @ 5,420 miles