The introduction of the ramp travel index (RTI) ramp provided a means by which vehicle suspension articulation could be quantified. By driving up a 20 degree incline, fourwheelers could measure axle movement, relative spring rate, frame flex, and also easily observe any component that might be limiting suspension movement. Now, many clubs have their own RTI ramps and even individuals are making makeshift ramps at home.

While the ramp is a useful tool for testing a suspension, it does not tell all about vehicle performance while fourwheeling. Much can be learned by using a ramp to test various suspension tweaks. However, there are still excellent trail vehicles that perform only so-so on a ramp, and also high ramp score vehicles that do not do as well as might be expected when pitted against formidable obstacles. Also, such variables as wheelbase, track width, tire pressure, etc. can affect the results to a significant degree.

With these new methods to check suspension travel and articulation come just as many ways to measure them. It seems there is no standard and everyone makes up their own measurement system. It would seem that a vehicle running 10 inch travel shocks mounted in a vertical position would have, as a maximum, 10 inches of axle travel, assuming the rest of the suspension is capable of such travel. Certainly, mounting the shocks at an angle less than vertical could allow more axle travel.

However, it is not uncommon these days to see writers and owners claiming huge travel figures. One Jeep in one of the popular magazines was claimed to have 33 inches of front axle travel using vertically mounted 14 inch travel shocks. In another recent article on the new Jeep TJ, the author claimed they measured 23 inches of travel with the sway bars removed. As such, without any type of standard, magazines and ads are free to quote whatever outrageous figure they please.

Travel should be measured as the true vertical distance the axle is capable of moving. For a live axle truck, this can be measured at any point on the axle. But, for an IFS truck, travel is best measured at the centerline of the tire.

Articulation is another measure of suspension capability. It can be described by how much the axle or suspension can move with one tire stretched to full suspension extension while the opposite tire is compressed to the short travel limit. Measure of articulation is hard to quantify, but an RTI ramp is one of the best, simplest approximations of such.

See ya on the trail......or the ramp.