prp chassis front end question

[emrtrx450r]

have gibson plus three a-arms on this chassis, have 4/1 wheels only a little over 47 inches wide, sooooo, what a-arms do i need 2 be closer to 50, help me out so i am not doin trial and error please.

[emrtrx450r]

sooooooooo i figure 4plus 1 a-arms burgard, unreliable, others?

[JonA]

put some 3 2 wheels on it:eek2:

[emrtrx450r]

had some on it, trying 2 eliminate most of my bump sterring issues

[LT250RMan]

Originally posted by emrtrx450r
sooooooooo i figure 4plus 1 a-arms burgard, unreliable, others?


Burgard makes good products but you have to be very patient and wait for your parts.

[chopp124]

3-2 wont make any difference on your bump steer just more strain on your ball joints and shocks. i ran 3-2 for awhile then went to +3 with 1-4 and it felt the same.

[LT250RMan]

Originally posted by chopp124
3-2 wont make any difference on your bump steer just more strain on your ball joints and shocks. i ran 3-2 for awhile then went to +3 with 1-4 and it felt the same.

You are wrong. When you move the tire farther away from the ball joints and tie rods ends it will throw the steering axis inclination off and will create bump steer.

[emrtrx450r]

thanks guys

[chopp124]

putting 3-2 offsetrims doesnt change the bumpsteer we proved this at the gibson shop when my buddy bought a guage that measured up and down travel to the spindal. u can put a car tire on it and it doesnt change bumpsteer. however it will change handling it will pull on the bars more and put more strain on ball joints and shocks. think about it if u have 0 bumpsteer meaning your spindal stays strait all the way through its motion, no matter what you put on it it will still stay strait all the way through its motion. its all about angles and pivot points. thats why so many kids gett hurt on the chinese bikes the tierods arent right. i have fixed at least 100 of them now

[chopp124]

leaverage was the word i was looking for when u go to an offset like 3-2. theres more leaverage on the rider from the wheels thats where the steering damper takes over. but leaverage and bumpsteer are 2 diff things

[LT250RMan]

Originally posted by chopp124
putting 3-2 offsetrims doesnt change the bumpsteer, u can put a car tire on it and it doesnt change bumpsteer. however it will change handling it will pull on the bars more and put more strain on ball joints and shocks


that is called bump steer when the suspension pulls on the bars and throws the steering off....lol

When you have a bunch of stress on the handles bars from offset rims and you hit some bumps, it makes the steering very hard and will cause it to push the handlebars around. It will also do this when landing jumps.

Oh ya im pretty sure that putting car rims and tires on a atv would create bumpsteer.

[D Bergstrom]

Originally posted by LT250RMan
that is called bump steer when the suspension pulls on the bars and throws the steering off.....lol

No it is not, chopp124 is correct. The definition of bumpsteer is the change in toe throughout suspension travel, what you are refering to is leverage, as chopp124 stated. Wheel offset does not affect bumpsteer.

To the original poster, if you are at 47" wide with +3 arms, then with +4's you would be 49" wide, so yes, if you goal is to get closer to 50", then you would want to run +4 arms. Not familiar with a PRP chassis, are they a narrow front? If so, you need to run +4 arms for close to 50" wide with 4:1 wheels. If it is not, then you should already be close to 50" wide, may need to check the way you are measuring.

Doug

[LT250RMan]

Originally posted by D Bergstrom
No it is not, chopp124 is correct. The definition of bumpsteer is the change in toe throughout suspension travel, what you are refering to is leverage, as chopp124 stated. Wheel offset does not affect bumpsteer.

Doug

Learn something new everyday..lol

[emrtrx450r]

Originally posted by D Bergstrom
No it is not, chopp124 is correct. The definition of bumpsteer is the change in toe throughout suspension travel, what you are refering to is leverage, as chopp124 stated. Wheel offset does not affect bumpsteer.

To the original poster, if you are at 47" wide with +3 arms, then with +4's you would be 49" wide, so yes, if you goal is to get closer to 50", then you would want to run +4 arms. Not familiar with a PRP chassis, are they a narrow front? If so, you need to run +4 arms for close to 50" wide with 4:1 wheels. If it is not, then you should already be close to 50" wide, may need to check the way you are measuring.

Doug
just 2 right angle on level floor measure between the 2, a tad over 47, so yes this is a narrow frame and yup w/ plus 3, so thanks need plus 4 set w/ the wheels i am confident in running, can am, which i owned rode a 09 xmx went through alot of trouble to figure all that stuff out has a narrow frame w/ long arms to achieve didnt do all that 4 no reason, i started this thread 2 see if anyone other than burgard had 4plus 1 a-arms 2 get me closer 2 50, i appreciate the help, ran stabilizers, diff. offsets, and so on from r's 2 ex's and so on if run wide a-arms w/4plus 1's it is easier to control when going fast thats all. oh yeah my arm pump comes on later w/ this set up also maybe a lil slow but been ridin and racin for 20 plus yrs. startin to figure out what works and what dont.

[chopp124]

my buddy is starting his shop again he made all the original gibson designes. i already have a request for +4 so if your looking ill get on him to get it going. doug roll wants 1500 for +
4 so im pretty sure he will be way under that. but its going to be a little while before he does. u can always contact roll design. corect me if im wrong but the laeger protrax is 47-48 wide with norrow chassis i thought those were the ****?

[chopp124]

i would hope im kinda right cause 10 years of gibson front ends couldnt be wrong at this point. lol

[josborn]

The wheel offset affects the steering axis inclination angle. In short, if you draw a line though the top and bottom ball joint, where it hits the ground is this angle. By moving the center of the tire in or out, you are effecting where that spot is on the contact patch of the tire. Most of the older honda spindles were designed such that running 4-1 wheels made this spot hit more in the center of the tire, thus better turning. Thats why most guys use 4-1 wheels, they turn better. It has no effect on bump steer. The relationship pivot points of your suspension system effect bump steer. All pivot points, but mainly the travel path of the a-arms vs the tie rods.

[emrtrx450r]

dont really have the terminology, but really all i am trying to achieve is handling, basicaly the best handling i can achieve w/ the correct parts spent so much time and throughout the yrs., listening to this and that, just want to get it all 2 gether and fine tune some stuff to get the quad to be the best it can be with me on it. may sound out there but i have put heart soul and many of hrs building buying settin things up to be completely frustrated and just get rid of it all 2 start over, if i am going to spend money and time want to feel achievement not deflated thanks

[LT250Racer609]

put what the quad originally had on it. The roll design Lobo 2 with the axis shocks. The quad measured 50" exactly and handled amazing.

[emrtrx450r]

hey, done a bunch of work to the quad, motor, new fronts, rear shock rebuild, on and on quad is at 48 and still handles like a dream just had some pre ride questions ridden on my practice a bunch, love the quad.

[LT250Racer609]

Originally posted by emrtrx450r
hey, done a bunch of work to the quad, motor, new fronts, rear shock rebuild, on and on quad is at 48 and still handles like a dream just had some pre ride questions ridden on my practice a bunch, love the quad.

sweet I want to see some pictures.

I take it you kept the front end still on it?