|
|
RAMP TRAVEL INDEX TEST
|
. |
 Sam of Sam's Off-Road and OKRovers were working on setting
a date for this for months. A few trail riding days got in the way, both from his side and ours,
several times, before we were able to find a suitable one.RTI scores indicate one thing only - articulation. While it has some bearing on a truck's off-road ability, there are so many other variables at play - driver experience being a big one, tire tread and tire size another, not to mention approach, departure, and breakover angles, and center of gravity - the list goes on. But this was a super cool club day, and we strongly encourage more members to make the next one. |
. |
| . | "Ramp Travel Index Summary on a 20 degree ramp as reported by Four Wheeler Magazine."
|
. |
 |
 |
. |
'93 AM General Hummer
580| . |
|
. |
The Ramp Travel Index or RTI as it is commonly referred to is a standard format for measuring a vehicles articulation - the ability for the vehicle to keep the wheels on the ground regardless of terrain. While many argue that rti scores have little to do with a vehicle's offroad ability, if nothing else, one should always ramp one's vehicle (especially after suspension modifications) to verify that there are no interference issues in the suspension or driveline. Click on the diagram to view an explanation of the RTI. |
. |
| . | RTI is a relatively simple calculation, and because the distance ramped is divided by the wheelbase of the vehicle, it really allows a comparison among various vehicles. To conduct an RTI test, the vehicle should be in four-wheel drive low range to allow easy speed control and traction. The vehicle is driven up the ramp on the driver's side until any other of the tires loses contact with the ground. At this time the driver stops and allows the inspector to measure the distance the front left tire traveled up the ramp (measured parallel to the ramp surface). Next, this distance is divided by the wheelbase and multiplied by 1000 to produce the RTI score. Example: A vehicle with a 88-inch wheelbase that travels up the ramp 48 inches would score as follows: 48 divided by 88 = 0.54 multiplied by 1000 = 540 RTI |
. |
| . | Rene Koelser - 590  |
. |
2000 Series II Discovery 100" wheelbase Stock tires. OME HD springs (front). OME MD springs (rear). OME long-travel shocks. |
. |
. |
 |
. |
| . |
Paul Davis - 625  |
. |
1997 Series I Discovery 100" wheelbase BFG All-Terrains OME HD springs and shocks. |
. |
 |
. |
| . |
Michael Baker - 710  |
. |
1998 Series I Discovery 100" wheelbase Stock Vehicle |
. |
 |
. |
| . |
Mark Kiely - 716  |
. |
1973 Series III Airportable (Lightweight) 88" wheelbase 265/75/16 Cooper Enforcer Mud Terrains. Rocky Mountain parabolic springs. ProComp Explorer shocks. |
. |
 |
. |
| . |
Brad Smith - 730  |
. |
2001 Series II Discovery 100" wheelbase Stock vehicle, with ACE system. |
. |
|
. |
| . |
Jim Royall - 730  |
. |
1996 Series I Discovery 100" wheelbase OME MD springs and shocks (2" lift). Removed anti-sway bars. 265/75/16 (32") Trxus MT radial tires. |
. |
 |
. |
| . |
Jim Thompson - 832  |
. |
1993 LWB Range Rover 108" wheelbase 235/85/16 Interco TrXus MTs, Removed anti-sway bars, ECR Stage II coil spring retro kit conversion from stock air suspension, with Fox racing shocks, and installed a 3 inch shock drop kit, and longer bump stops, modified radius arms. |
. |
 |
. |
| . |
Randy Black - 867  |
. |
1995 Defender 90 Station Wagon 92.9" wheelbase 265/75/16 BFG Mud Terrains. Removed sway bars. Stock springs and shocks. |
. |
 |
. |
| . |
David Williams - 920  |
. |
1994 Defender 90 92.9" wheelbase 285/75/16 TrXus MT Super Swampers. Safari Gard stage II JEK suspension Rockware rear trailing links Removed anti-sway bars. |
. |
 |
. |
| . |
 |
. |
Results were interesting, probably most notable was the simple removal of anti-sway bars leading to a much improved score. Also interesting was the stock SI Discovery (Michael Baker), and stock SII Discovery (Brad Smith) ramped alot higher than the same vehicles (Paul Davis SI, and Rene Koesler SII) with the OME 2" suspension lift. And so, some of us went away deliriously satisfied, and others left not so happy. But all of us came away after another cool club event, getting to know our vehicles better and better, having made some more friends, and all looking forward to our next off-pavement event. Photography Brad Smith & Jim Thompson |
. |
| . | "I had done so much work on it I didn't know what to expect, I was pleased that it was as good as any other Discovery that tested." Jim Royall "I was surprised that my stock Disco held its own against modified Rovers." Michael Baker "I was impressed in seeing what my D90 can really do." David Williams "As a D-90 owner, I'm always surprised how well a stock Disco performs off the showroom floor!!!" Randy Black "Very interesting and at the same time very disturbing due to the reduced ability over a 'stock' DII." Rene Koesler "After altering suspension and tires, I was glad to have the opportunity to compare a stock Disco." Paul Davis "I didn't know what to expect but was pleasantly suprised." Brad Smith "East Coast Rover did a fantastic job in switching my EAS to a coil suspension which provides a balanced and expedition tolerant system that dramatically increased the off-road capability of a LWB RR." Jim Thompson "With the Rocky Mountain parabolic spring conversion, I was expecting the typical 100 point increase over a stock 88" score, but I was delighted to score so high with a leaf-sprung Rover." Mark Kiely |
. |