Need the RTI ramp formula

[JoshC]

Hey guys, i finally got to put my truck on the RTI ramp today. It was a 25 degree ramp. Anyone have the formula for that ramp?

 

[mrboyle]

http://mark.legendz.com/ramp.html

 

[Robb]

http://www.4wheelerssupply.com/Tech/rti_calculator.php

 

[JoshC]

Thanks guys. I tried the ramp twice, going forward and going up in reverse.

Going forward i scored a 1225 on a 25 degree ramp. I got 58 inches up the ramp this way.

In reverse i scored a 1627. I got 77 inches this way. I was pleased with the front flex.

I don't know anything about RTI ramps and the scores, is that decent?

 

[mrboyle]

A score of 1000 is supposed to be perfect. So anything over is excellent.

 

[Maniak]

When you said you drove "up" 58".. do you mean the vertical height of the tire was 58" or do you mean you drove up the ramp a distance of 58"?

If you drove up the ramp 58" the verticle tire height would be 24.5" or so.. which is an rti score of 557 on a 25 degree ramp (689 on a 20 degree ramp). I used 104" as the wheelbase of the Explorer.

Without major work, getting a score of 1000 is pretty hard to do.

Score of 600-800 on a 20 degree ramp is more common. Bone stock I believe the Explorer got a score of 500ish (I can't remember)


~Mark

 

[JoshC]

I drove up the ramp 58 with my front tire on a 25 degree ramp and my wheel base is 112.

 

[Randall]

Originally posted by JoshC
I drove up the ramp 58 with my front tire on a 25 degree ramp and my wheel base is 112.

Are you measuring from the ground directly below your tire to your tire (a), or from the end of the ramp to your tire (b)? You are supposed to measure A.

 

[JoshC]

Alright, well he measured from the wrong place then. He measured from the end of the ramp to center of the wheel. If i hadn't forgotten all my math i'd figure that out!

So the B measurement has nothing to do with it then?

 

[Maniak]

ACtually, that does matter.. but if you measure from the end of the ramp to the center of the tire, you just take the # of inches you drove up and divide by your wheelbase.

The formula that is used in http:mark.legendz.com/ramp.html is for people who don't have a ramp so they can't measure from the bottom of the ramp to the tire. Those people have different number so we have to use a little Trig to figure out the missing number.

You have the easy to numbers... so 58" up the ramp divided by 112" wheelbase gives you an RTI of 517 on a 25 degree ramp.

~Mark

 

[JoshC]

Alright, thanks for clearing that up for me Mark, that makes more sense then for that kind of score.