OTT Steering Opinions

[ack]

From the Wikipedia:

http://en.wikipedia.org/wiki/Panhard_rod

The Panhard bar (or rod) simply changes which end of the draglink "gives" - the suspension end as opposed to the pitman arm end.  Note also that panhard bars are generally used on coil spring suspensions as leaf springs tens to hold the axle in place better than a panhard bar (see link above).


Your choices are this: 

Do you care if the axle moves side-to-side during suspension loading/unloading by using a panhard bar?

Do you want to use a Z-link and live with bumpsteer during suspension loading/unloading?

Do you want to install an OTT system and nearly eliminate both bumpsteer AND side-to-side axle movement during suspension loading and unloading?

And yes, boggdeep4x4 is exactly right in the observation that a panhard bar must be parallel to the draglink (or, at least, the pivot ends of the panhard and the draglink form the endpoints of a true parallelogram). 

However, that parallelogram alignment can change during suspension loading/unloading which might not make a panhard bar work as well to eliminate bumpsteer like an properly-designed OTT setup can.

Ahhh, the choices...  So many types for different purposes - and they all interact with the rest of the vehicle to different degrees...

I hope that this helps!  And I hope your eyes didn't glaze over reading this stuff.   

[prowler]

so a proper OTT setup doesnt need a panhard bar?

is it true that a ful OTT affects the ackerman angle?

TIA
KiD

sorry for all the questions, just trying to learn a thing or two

[HardLuk]

boggdeep4x4 -- A leaf sprung truck does not need a panhard bar.  The leaf spring's job is to multitask and do many jobs all at once.

1) Suspend the truck
2) locate the axle side-to-side
3) locate the axle back to front

The reason some of us choose to run a panhard rod, even on a leaf sprung truck, is to try and get as accurate of steering as possible, get back a good turn radius, help the truck track better on roads, and to get as much steering as possible when off road pinning tires against rocks or drooping into holes.  These are not the only reasons, but most of them.

Long shackles and missing link type shackles introduce more play in a leaf spring suspension due to leverage and extra joints.  When this happens the accuracy of the steering is compromised and an increase in the amount the wheel turns before actually turning the tires occurs.

Even if you run an OTT setup, which will considerably reduced bump steer, ideally by bringing the drag link up the same amount of inches as your lift, you will still get less accuracy of steering than someone running a panhard rod.

So, both are best, but if you had to choose one, it would be the OTT setup, because bump steer sucks, and as a panhard bar can neutralize bump steer, it's not desirable to have in conjunction with a drag link that is at too steep an angle. 

Like Ack said, it's a matter of parallelograms, and if the suspension is going through a lot of motion, the geometry is bound to be off a little at points of suspension travel.  But with a fairly level panhard rod/drag link, and under regular driving conditions on road, and as long as the angle of the panhard matches that of the drag link (while attempting to be as long as the drag link in length), then the chassis will only move slightly side to side as the panhard swings on it's radius, effectively relieving the strain (taking the place of) on the drag link, which would be doing the same thing (moving the chassis side to side -  or actually, the pitman arm since it's easier to move) if the panhard was not doing it instead. 

****The panhard is a solid bar that is moving the truck over (in relation to the axle) the same amount the drag link would have moved the pitman arm (bumpsteer), resulting in a neutralization of BUMPSTEER and nice tight steering as the axle can not move left or right with steering input (in relation to the truck)****

[fordcustom]

this is the best pick i have of my mercedes arms.... i retapered them the other way so i could mount the tie rod on top to clear my springs..

[ack]

Excellent description hardluck!

Not being a panhard person, your post helped me better understand panhards as they apply to our vehicles!

...About the Ackerman angle:

http://www.rctek.com/technical/handling/ackerman_steering_principle.html

(found at Ack's FAQ by searching for ackerman) Pulling web articles out of my butt like never before!

If the new OTT steering arms were not positioned exactly the same as the OEM arms, then a dicussion of the Ackerman Angle might be useful.    Logic dictates that an OTT vendor (even RRO! ) would leave their OTT steering arms exactly positioned as the OEM arms so as to not throw yet another variable into the steering mix.  Oh and that would only apply to OTTs that move the tierod position - like the RRO stage II and others.

As Commander Spock said in and episode of the original Star Trek series:

"The difference that represents no difference IS no difference".

[ack]

Danged Forum Modify function won't work for me!

If you look at fordcustom's mercedes arm install pic (above), you'll notice that the tierod connection is inboard of the OEM connection by possibly 1-2 inches.

That being the case, the Ackerman Angle has been changed on his truck (see link in my last post - above).

Does this mean anything in our application (Samurais)?  Maybe yes, maybe no.

[fordcustom]

if you like to play with geometry..

the arm being angled in more from the knucles piviot point..  as you turn the wheel to the left or the right, the outside tire turns sharper than the inside tire... 

 this decreases tire slippage (scuffing) of your outside tire)   slippage=loss of traction

if you think about it..when turning a corner your inside tire does not need to turn as fast as the outside..

i imagine mercedes put a little more thought into the handling of there stability/performance of there car than suzuki....

[fordcustom]

it's kinda hard to explain but on the show "Junkyard wars" there was an episode where the were running an opsticle coarse in llittle cars.. anyways.. there was a very good illustration and demo video that explained how it worked... you may check out youtube...

[prowler]

thanks guys. i think im going to go half high steering with panhard bar

[fordcustom]

i payed $15 for my mercedes arms at the junk yard... whats high steer cost..

[fordcustom]

i just looked at your pic in the first post..  you may run into an issue with those lift blocks.. i beleive your tie rod is going to try to run through your spring..  you may have to pull the blocks so you can evan run high steer...


shame on you for putting blocks on the front   most states in the "lift laws" don't allow blocks on the front only rear..  and those would also contribute greatly to why you need a panhard bar..

[DrJekyl5]

The taller spoa spring perches were already installed when I bought the zuk.  They are 5.5", maybe the RR model I suspect.  I think I am going to have to go with RR OTT setup, as they have raised arms to compensate for taller lift heights.

[fordcustom]

well.. the driverside looks like it has a block but when you think about it... the axels arn't that big... 

cancel some of that in my last post...    i blame it on the camera angle... lol...

[One Sick Puppy]

Sky stage 1 here. Seems good to me.

[DrJekyl5]

The sky kit doesn't look like it has enough spring clearance for my taller perches.

I really like that bumper.  Where did you get it?