wayoflife

Okay boys and girls, WOLette and I finally got a chance to do some detailed ramp testing over at Off Road Evolution and generated some RTI scores that shows just how amazingly well their new EVO Flex System performs and with just a good set of adjustable aftermarket short arms. So you know, all our testing was done with Off Road Evolutions supervision to ensure accuracy. Also, you should note that we are currently running 37" tires with TeraFlex Flex Arms although, I have little doubt that any good set of adjustable short control arms would perform just as well.

For those of you who have no idea what I'm talking about, an RTI or Ramp Travel Index score is a tool to help you measure a vehicle's ability to flex or articulate its suspension. Ramps can vary between 15-30 degrees of angle but most people tend to work off of a 20° ramp. To score a vehicle, you would put one tire on the ramp and drive up it until one of the other three tires starts to lift off the ground. Once that occurs, you back down the vehicle until all the tires are making solid contact with the ground again and then you start to take measurements. To make your calculations, you need to do the following:

1. Measure the distance traveled up the ramp (to center of wheel).
2. Divide that measurement by the length of the vehicles wheelbase (Jeep JK Wrangler Unlimited = 116 inches).
3. Multiply that number by 1000

The final number you get is your RTI score and in the case of a stock Jeep JK Wrangler Rubicon Unlimited, that number just so happens to be a very impressive 706 (as HOMEGLASS had quoted from an off road enthusiast magazine).

Now, as mentioned, most people tend to use a 20° ramp to calculate their RTI scores but for our purposes, we decided to use a steeper 30° ramp that Off Road Evolution has at their shop. However, I will provide our RTI scores for both a 30° and 20° ramp just give you a good perspective on things. Also, we did our test twice - once with our tires at 26 psi (street pressure) and once at 10 psi (trail pressure). However, before I do that, here are some pics from our testing...

Shot of what a 30° ramp looks like....


These lines represent what various other JK's have been able to reach. The dark green line at the bottom is a stock JK Rubicon Unlimited, the sliver line above that is a 4-link long arm kit with 37" tires (street pressure), the orange line above that is a 4-link short arm kit with 37" tires (street pressure) and 12" EVO front coilovers (only) and the neon green line above that is a 4-link long arm kit with 37" tires (street pressure), 12" EVO front coilsover and rear EVO lever....



Here are some shots of us going forward on the RTI ramp with our tires at street pressure...








Here you can see that at the center of the wheel, we got a distance measurement of 82"...


Here are a few shots backing up the ramp...








Now, this is what we were getting with our tires at 10psi (trail pressure)...








Just so it's clear, we made absolutely sure that all four tires were making solid contact with the ground/ramp and that our Jeep was completely stable before taking any measurements. Having said all that, the moment of truth is finally at hand.

The printout on the left is what we were seeing with 26psi in our tires and the printout on the right is what we were seeing with 10 psi....


20° Ramp w/26psi = 1033.47 (46% gain over stock)
20° Ramp w/10psi = 1146.90 (62% gain over stock)

30° Ramp w/26psi = 706.90
30° Ramp w/10psi = 784.48

As you can see, on a 20° ramp, we were able to achieve a huge RTI score of 1033.47 (46% gain over stock) with 26psi in our tires and with 10psi, we were able to achieve an amazing RTI score of 1146.90 (62% gain over stock) and all this with short arms!! Just as a reminder, a stock Rubicon Unlimited scored 706 and to give you some perspective on things, according to an off road enthusiast magazine, their project JK with RE long arm kit sitting on 37" tires was only able to score a 776 or just about a 10% gain over stock.

To give you all a little background on things, I have been running the Off Road Evolution EVO front coilovers and rear EVO Lever on my JK for a little over a month now. I have driven this extremely comfortable and stable riding JK to and from far away trails, some more than 500 miles away and at speeds of 85 MPH. I have driven it at speeds of up to 60-65 MPH on desert roads and the fine tuned coilovers designed specifically for JK's just soaked up the bumps and provided a smooth ride. And, I have tackled tough rock crawling trails such as Niagara Rim and Bronco Peak with ease thanks to the fact that the stupid crazy flex I now have do such a great job of keeping all four on the floor which in turn offers great traction and even better stability.

So, what does all this mean to anyone? Well, based on my experience, it is my opinion that up to 37" tires, a long arm kit simply isn't needed. If you want a great ride and unsurpassed flex, a good set of adjustable short contol arms, an EVO front coilover and rear EVO lever is really the way to go.

bly109

Just keep rubbing it in.......

Gokracer1

Yes they are, that suspension has still got me in ....

2drREDROCK

Thanks,now I can figure out how to calculate the RTI.
That is amazing,thanks for the pics they are awesome


How about we try a TWO DOOR next

08{GA}RUBICON

That's awesome! I'm weeping........

wayoflife

yeah, i have to say that the scores are really insane and way more than i think any of us were expecting. i mean, even with our tires at street pressure, we easily out scored JK unlimiteds with 37's tires and long arm kits installed - even 4-link setups. however, based on what we could see, 37's really are as big as you can go. if you want to run 40's like Off Road Evolution is now, you really do need a long arm kit. on their JK with a full traction long arm kit, EVO flex system and 40's, i don't think they have enough ramp to get a maximum score.

SGT.

WOW.....

bofer84

Hey WOL....so, if im correct, the only thing really needed is a good 3"-4" lift, (insert currie 3.5 if your me) and the evo system??? Or, if your planning on going the evo route, are you better off getting a good set of adjustable arms..(insert whoever FT, currie, clayton etc..) and then the evo system front and rear??

fish

that is sweet WOL
i look forward to getting my jeep to that point someday

wayoflife

actually, all you really need are a good set of control arms (like the set of currie's that you have now), front track bar relocation bracket, front adjustable track bar, extended brakelines, front drive shaft if you have an auto, rear drive shaft if you have a 2-door and that's about it. add the EVO flex system and you're done. your old coils, shocks, swaybar links, rear track bar relocation bracket and/or rear adjustable track bar won't be needed. like you, i already had a good short arm kit installed and so making the jump to the EVO flex system was easy to do. certainly, you already have a lot of the componets you will need to make the EVO flex system work and it can be done for about the same price as upgrading to something like an RE long arm kit. for me, going this route offered way more bang for my buck.