scott  30 rr lr   33.5 rf  37.5 lf
ack   21 rf   23 lf
barbie  18 rf    21.5  lf
dave greene   42  rf  42  lf    37  rr  51  lr
wilson    21   rf    17   lf
fling    66  rf      68  lf  no rear taken
sleepy   36  rf    35   lf
eric     21   lf    21    rf
gary fling  31   rf    24  lf
skyhighranger      37  rf   41     lf      41    lr      31     rr   ( most balanced rig )


take each individual score and divide by wheelbase.
if you want overall score   average then divide.

any 's
leave anyone out?     

That can't be right.......
 

ok   ill look into it

I'm pretty sure my RR should be 41 too....at least I think you told me they were all 41, except for the RF at 37

damn   im screwing up left and right  ill recheck all figures and you are right kevin all were 41 but one.

if you average all wheels that is combined score on 30 degree   but i still cant get a straight answer about how to divide it.

help !!

That is the correct calculation for figuring RTI......(I think the "proper" way to "express" RTI of a particuliar rig, is to either average all the scores, or do the front axle and rear axle independently) .  But it doesn't take into account whether you are on a 20* ramp or a 40* ramp. 
BTW, what degree ramp was that one yesterday?

Here is a chart that I ran across a long time ago, to show actual axle articulation, when using a 20* ramp....I am sure that one yesterday wasn't a 20*...but kind of a neat chart none the less.

30   degree   thats the standard anymore with the rock crawling crowd, so it seems.

i think you are right about it being per axle.   not sure about the dividing part yet but the numbers im coming up with seem plausible.

You figure RTI like you said Flea......divide the inches traveled up the ramp by the wheelbase, then multiply that by 1000=RTI.  As I said, you can figure it by averaging the "4 corners" or by averaging each axle by independently.  But that does not take into account whether it was figured on a 20* or 30* ramp.  There is a lot of difference between a 1000 RTI score on a 20*, compared to a 30*.

I think your math is stable it is your definition that is shakey,
take your rti score (most of the time it is LF) and divide it by your total wheelbase
this will give you a number in decimal form, simply mulitply by 1000 and that is your score.
you could also contact pure evil (brent) on izook he has been running the one at zukimelt for years.

here is an example of my LF this year at zukimelt (30* ramp)
70"                             
(distance on ramp)
80"
(wheelbase)

70 divided by 80 = .875 times 1000 = 875

the scoring is the same on any angle ramp but of course your score would vary by each ramps angle

sorry about that skyhigh I am a little slow on the posting

pe  is a member here  maybe he will stop by again.

That's what I said!!!.....in a round-about way.   I sometimes don't explain things very well.
And as far as whether you want to measure just one corner, 2 corners, or all 4 corners (average or otherwise) to figure your RTI....that is a personal decision.....I don't know that there is an official "rule" on how it has to be done.  But, IMO, a "true" RTI calculation would be made by taking measurements from all 4 corners.....since very rarely will you find a vehicle that will flex exactly the same both driving up the ramp and backing up the ramp.

I know that is what you said and that is what my apology was for,
it is just that as I was about to post it came up and informed me you had posted,
I just hated to loose all that typen and also the fact that I am not very good at getting many posts on boards
I also agree that a four corners is probably better, but I am sure I am not alone when I take the biggest risks with my side of the rig as I can see what I am driving over, so I think that drivers front is the most important as you can always goose it to bring the back end down

the ramp was there we had time people were entertained and it was all good !!!


big thank you to billjohn from IZOOK

No problem.....sometimes I need someone to help me say what I am trying to say (that doesn't make sense either, does it ).

THANK YOU BILLJOHN   from IZOOK

he sent me this link

http://www.billjohn.com/rti/index.htm

cool, you all ought to plan on coming to rocktoberfest also, if nothing else us zuk's can start our own herd down there, I know a lot of the people and all of them that put it on, I normally volunteer also.

may be in the willyz thoug, but the sami will be there to.

I WILL be there in 08.
already on the calander. bringing the whole family.

i had a blast there in 99? and have wanted to get back ever since.  i fell in love with fayetteville during that trip.  almost got married in some famous chapel in eureka springs but i chickened out.
 

When and where is Rocktober  fest?         Mel

it is the weekend before halloween in cass arkansas it is hosted by the rockcrawlers 4x4 club.
here is a link
http://www.rockcrawlers4x4.com/Downloads/Rocktoberfest%202007a.pdf
our website has had a lot of trouble this year and the new one is still not great yet, but I can try to answer any questions.
also check out http://www.byrdsadventurecenter.com/ cool place ran by good people.
thanks
andy

So, what I got (Rounding to integers) was:

Barbie = 497
Wilson = 553
Sleepy = 935

see one  I Told You So !!  about Sleepy to Jeff !!!!!

very respectable smuz !!!!!

only thing holding barbie down was body panels !!!!

I've been quiet thus far because I'm not familiar with RTI, and I left it up to others.  There seems to be some confusion, so I find it necessary to sort this out.  Flea's figures are fine, they just need to be adjusted.

• We used a 30 degree ramp.
• The ramp graduations are based on Distance Traveled Up
• The distance measured was based upon a vertical plane.
• Distance Traveled Up ramps must use a measurement based upon a plane perpendicular to the ramp.
• To compensate, add the following number of inches to your "raw score" to determine the proper Distance Traveled Up

Tire    Inches
Size   to Add
37    11
35    10.5
33    10
31    9.25
29    8.75
27    8.25



I'm working on a formula based on the 30 degree ramp that we used.  All I've been able to fine thus far are based upon a 20 degree ramp, and/or Distance From Ground measurements rather than Distance Traveled measurements.  I'll get back to you .

I am pretty sure the numbers that Flea was writing down was the inches traveled up the ramp, not the vertical height the tire was off the ground.
Figuring RTI is as simple as this......since everyone's numbers are from the same angle ramp....the ramp angle does not come into play to determine who has the best RTI numbers.  The ramp angle comes into play when you are trying to determine how far the tire up the ramp was off the ground (vertical plane), which you need to figure (to adjust RTI), if you are comparing 2 vehicles, that were RTI'd on 2 different angle ramps.  Make sense?
Anyway, in our case.....
You simply take the inches traveled up the ramp, divided by the rigs wheelbase, multiply that by 1000, that equals the rigs RTI.
Now, how you determine which number(s) you are going to use for the inches traveled up the ramp, that is the question....it really doesn't matter, as long as you figure everyones the same way....for example, for mine the numbers were 41, 41, 37 and 41 and my rigs wheelbase is 79.9", so I can ....
1) average each axle and figure RTI per axle...
(41+41)/2=41, 41/79.9=.513, .513x1000=513 RTI
(37+41)/2=39, 39/79.9=.488, .488x1000=488 RTI

2) average each axle, figure RTI per axle, then average the RTI for the 2 axles...
(513+488)/2=500.5 average RTI for both axles

3) average all 4 numbers and figure RTI....
(41+41+37+41)/4=40, 40/79.9=.501, .501x1000=501 RTI

Like I said, it doesn't matter which method you use, when determining which number(s) to use for inches traveled up the ramp, just use the same method for everyone, that way the RTI is figured the same way for everyone.

That's true.

I realize the measurement may not have been taken correctly.  But for comparison purposes for determining the ranking of the "contest", it doesn't matter, since all measurements were taken the same way. 
Bottom line....take each rig's measurements from Sunday (averaged or otherwise), divide by the wheelbase, multiply by 1000, and that will give you each rig's "score" (I won't call it RTI, since it is technically not figured with the correct ramp numbers, to be called RTI).

That's true, obvious even.  However, I think that the participants would like to have their actual RTI score, so they can compare their numbers to other rig's RTI scores measured on different ramps.  To do this , we have to convert the "score" from our 30 degree ramp (with the correction above) to RTI for a 20 degree ramp. 

To determine your actual RTI:
[1] Take the number Flea provided at the top of this thread
[2] Add the correction that I gave later down that corresponds to your tire size
[3] Divide the results by your wheelbase
[4] Multiply this by 1000
[5] Goto:  http://www.therangerstation.com/tech_library/RTIcalculators.htm
[6] At the bottom of the page, in the section entitled "Convert an RTI From One Angle to Another"
[7] Enter your Wheelbase
[8] Enter the figure that you calculated where it says "Original RTI"
[9] Enter "30" where it says "Original Ramp Angle (degrees)"
[10] Enter "20" where it says "New Ramp Angle (degrees)"
[11] Click on "Calculate"
[12] The number that appears at "New RTI" is your actual RTI and the number that you're looking for. 

Please understand that I'm trying to get this right.  I welcome any necessary correction from anyone with a clue.  If I screwed anything up, please let me know.

Your #2 above will not necessarily give the right corrected figure (i.e....most tires do not measure the stated sidewall size; and even if you use actual measured sidewall height, all tires (aired down tires, especially), will compress more with more weight put on them (like when running them up a ramp)....so therefore, there isn't really a good (accurate) way to adjust the "mismeasured" numbers, IMO.  Yeah, the adjusted measurement will be "close", but if wanting to compare "apples to apples", the correct measurement should have been taken in the first place, obviously.

I would hope that his is obvious to most of us.  Sure, consider the tire sizes as "effective tire sizes".   

yup, you be right....... duh!

So here's what I get for average front axles using George's corrections:
Sleepy = 569
Wilson = 356
Barbie = 309

Using BillJohn's calculator to convert to a 20 degree ramp:
Sleepy = 831
Wilson = 520
Barbie = 452

Now be these numbers right or wrong, I think I am THRU with this! My little fat head hurts.

Here are the results that I came up with your corrected figures...                                                                                  Stretch @ 95" wb             864.52 on 30 degree                1263.84 on 20 degree                                                           Gary's Tracker 86" wb     427.33 on 30 degree                  624.71 on 20 degree                                                           The yellow "Stretch" Samurai has a coil-spring front three link and a quarter-elipticle rear, 33" shocks w/limit straps.  I have limited the travel a bit for comfortable stability.  Since I first took the Samurai to Disney, Ok the front suspension limit straps were adjusted 2" shorter.  That gave me a better feel of the body roll over.  Keep in mind that your center of gravity is most important.  You can build a flex vehicle that won't wheel very well, if your center of gravity is to high.  Other Samurai vehicles that I have had, with close to stock wheel base 80-84", worked best for me with about a 850 rti on a 20 degree ramp.  To each thier own, go out and have fun!                Gary Fling's (dad) Tracker has a Calmini 3" suspension lift, on 31" Truxus MT.  Makes for a nice drive and play vehicle.