Mile 236,567: RTI Test Simulation (With howto)

So thanks to me seeing someone else do this, I did an RTI test with a jack, took pics too. Measured clearance from ground to the tire in the air was 13", all four tires had contact with the ground. Here's a picture of me doing the test. I scored a 376.


Here's a stretch photo:


I did this as kind of a baseline test before I started modding, also wanted to describe how to do this kind of RTI test (as well as how to get your score)

An RTI Test is defined as such (sited from 4lo.com)
Ramp Travel Index is based on climbing a 20 degree ramp with one tire while keeping the trailing tire in line. At the point where any tire begins to lift into the air is where it's calculated. Measure from the bottom of the ramp to the center of the bottom of the tire (use a plumb from the hub to find center). This distance traveled in inches is divided by the wheelbase in inches and multiplied by 1000. What this gives you is a percentage of travel up the ramp in relation to your wheelbase.

Formula:
RTI = Tire Height/sin(20*PI/180)/Wheelbase*1000

Things you will need:
- 2 jacks or one jackstand and one jack, one of which should be the floorjack style and the other should be a straight-up design and preferably mechanical (such as a scissor lift)

Note: The jackstand is a safety measurement and is not required, but HIGHLY RECOMMENDED!

- Tape measure
- Wheelbase measurement (101" on XJ's) (http://www.cherokeeforum.com/showthread.php?t=6345)
- RTI Calculation formula/calculator (http://www.4lo.com/calc/rticalc.htm)

Extra skills and things needed:
- 4wd Engaged
- A good sense of safety/smarts
- Ability to operate jack

This project is rated at 0 of 5 dirty rags (my hands are still clean, some ground crawling) and 1 of 5 wrenches (some special stuff needed, must know jack points and jack capabilities)

Quick note: Having a jack that lifts straight up (such as a scissor lift or bottle-style jack) is extremely handy, as hydraulic arm jacks will more easily dislodge at the higher end of their lifting capability, this may not be an issue on SMOOTH pavement.

Before you begin, make SURE your 4wd is engaged and emergency brake is on. This will keep your front wheel from having too much play in it when you lift it. If you do not engage 4wd or take other such safety measures, you risk heavy machinery (such as your vehicle and the jack) moving at high speeds in close proximity to each other AND YOU. Also make sure all of your tires are properly inflated to avoid a blowout.

To begin, lift up your front wheel (pick either driver's side or passenger side) high enough to fit your jack under the bottom of the tire. Make sure that when you place the jack under the tire, it is located at the BOTTOM of the tire. Very carefully raise the tire, keeping the jackstand as close to the axle as possible (watch your fingers, keep your head low.). Continue to lift your front wheel while watching the back wheel on the same side. As soon as the back wheel breaks free from the ground, lower your front wheel until the back wheel reconnects with the ground. This is the point where you will measure your RTI. Measure from the base of the wheel to the ground. Take this measurement and use it in the RTI calculator linked above. Fill in the Inches tire above ground and Wheelbase Inches section.

Congratulations, you have successfully measured your RTI score!