Crossovert steering: Will this allow softer ride?

[Jaco Versfeld]

Hi There,

What are the advantages and disadvantages of a crossover steering conversion. Will this allow a softer ride? Will this compromise the safety of the vehicle in any way?

As far as I can gather, the main reasons are for:
1. improved articulation,
2. getting critical components out of harms way.

Do I need to remove the bracket of the torque rod on the diff housing, when I do a crossover modification? (I would rather leave the diff as is, in order to change back later if needed ...)

I can't get a definite answer, but will the high steer prevent the leave springs from fatigue (the reason why the torque rod is there in the first place)?

How reliable is the IFS steering pump versus the SFA pump?

What kits are available, and which one is the best? (I see both Trail Gear and Marlin Crawler has kits, but don't know whether this is for right hand drive vehicles.)

Thanks,
Jaco

[Hoppy]

I run a cross-over steering system with a KZTE box or my SFA challenge truck, all my arms were coustom built in-house, i lengthened my torque rod to get even more articulation, you have to keep the rod to save your springs( they wind up on braking and acceleration).

It won't give a softer ride, but it gets rid of bump steer and steering under braking.

[Hoppy]

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Some pics on another one we did.

[Mud Dog]

Agree that it won't really contribute to a softer ride, not even if the torque rod is removed .... ride comfort is more a co-efficient of the spring tension, shock stiffness and the unsprung weight.

What Allan says about the torque rod is true, but I don't agree entirely that the rod is necessary with x-over steering.

The torque rod is responsible for a fair amount of articulation restriction. The reason for this is that it's radius is only about two thirds the length of the spring radius and the travel arcs therefore differ. This difference is somewhat offset by the offset positioning of the rod hanger by comparison to the spring hanger, but they still travel through different arcs. This causes a little forced but controlled axle wrap and it's what causes the small amount of bump-steer that the SFA's (with push-pull steering) are known for. It's really not the best example of Japanese engineering, but with push-pull steering it minimises bump-steer and brake-steer effectively. With x-over steering this is a non issue and the torque rod is a hindrance.

Another small benefit of the torque rod is that when the axle is extended outwards, the forced axle wrap mentioned earlier causes the pinion to wrap upwards a little, which is of benefit to the prop and universals, although not much. That small benefit is really only achieved on more severe off-road conditions, so IRO the overall picture on this issue, the rod can be dispensed of.

With or without the rod there is going to be some axle wrap and the springs are going to bear the brunt if this and under normal circumstances this too is a non-issue .... the rear springs have no stabiliser on the axle and they cope just fine with continuous braking and acceleration. However, where I do agree with Allan in keeping the rod is that the braking dynamic between front and rear axles differs vastly.

When braking, the weight of the vehicle is thrown forward onto the front axle which causes the front to be responsible for most of the braking power by far. This is why there are discs on front and only drums at the back, or bigger discs and callipers in front than on the back. Bear in mind that acceleration wrap is nothing by comparison to brake wrap, the forces are far greater in the latter ... remember it may require a full kilometre to accelerate from 0 to 120 kph, but deceleration from 120 to 0 kph can be achieved in about only 50 meters, roughly one twentieth of the distance, so roughly 20 time the force of the wrap. The springs have to cope with it ... not good for them. So this is where the torque rod is not entirely necessary but definitely a preferred piece of equipment.

I'm not saying keep it in or remove it ... just pointing out the issues.

The ideal IMHO would be to have a removable rod, and only take it off when off-roading.

[Aquanaut]

Hi Guys, excuse my ignorance, but what is the purpose of a cross over steering?

[Mud Dog]

Basil, this is a modification that the SFA guys do, most often because they have a problem with the steering box .... a new one costs over 5k, whereas a new one for an IFS costs a little over 2k. They operate differently ... the Pitman arm on an SFA box tracks back and fro while on the IFS box it tracks from side to side. In order to adapt an IFS box to an SFA, one has to do the x-over steering mod. Then there's x-over hi-steer and x-over lo-steer .... the hi-steer option lifts the tie-rod above the springs and out of harm's way.

[Aquanaut]

Is this something that everyone has to do sometime or other or is it personal preference like changing the suspension to an Iron Man or OME system?

[Mud Dog]

No there are other options, like having the old box re-conned, finding a good 2nd hand one or bending over and paying the dealer price for a new one.

[doppies]

I do have one big problem with cross over steer, and that is the ball joint on the pitman arm. If you have a close look at the KZ (IFS) you will notice that the ball joint on the pitman arm rotate only around himself and there is not sideway movements on the joint. If jou remove the link attached on this joint, jou wil find the joint is not design to make such sideway angels. Now you put this steerbox into your SFA for cross over steer. From this joint of the pitman you set up a link/rod going down to the knuckle housing. If you study the travel of the suspension, you notice the link/rod between the pitmanjoint and the knuckle housing going up and down. As refer, that ball joint on the pitman are not design to work up and down and you may get some ''hefboom'' stress on that joint. Very dangerous conversion.

[Mud Dog]

Willem, I'm not sure what it is you're trying to explain. Truth is that this is a very common and successful conversion ... never heard of any failures or problematic issues as long as there is no fouling with the springs. I cannot see what the danger is that you speak of and I suspect you have a misconception of what x-over steering is about .... the drag-link does not go down to the knuckle, it crosses over to the far side steering arm. Here is a pic that shows it fairly well, even though this is a left hand drive vehicle. If indeed this is what you envisage x-over steering to be, then explain where the problem is that you speak of.
Thanks.

[Mr_B]

Must say I've never seen a x-over steering SFA with issues at that joint... unlike the SFA pitman arm, the IFS pitman doesn't have a ball joint on the one end. It has a tapered hole to accept a tie rod ball joint. These ball joints have more than enough movement for decent articulation.

[doppies]

Andy, ek bedoel nie om die x over steer sleg te maak nie, maar wil net 'n '' mechanical failer'' uitwys in onkundige se hande. Ek reken ook dit is 'n baie goeie ombouing deur kundiges met ondervinding. ek het geen verkeerde indruk van hoe hierdie ombouing werk nie, inteendeel, ek myself het een so 'n x over steer ombouing gedoen en dit is een aspek wat my baie gehinder het' die pitman arm van die IFS. Mr B het verwys dat die IFS se pitman arm op die stuurkas 'n tipe is met 'n taper gat waardeur die skoefdraad gedeelte met taper body van die balljoint getrek word. Korrek, maar daadie pitman arm is DEFNITIEF nie afkomstig van die KZ modelle nie. Op die KZ modelle is die balljoint 'n intergrale komponent van die pitman arm self en die taper ligaam met skroefdraad boud was aan 'n arm [rely rod] wat weer verbind is met 'n idler arm op die oorkant van die chassis. Die rely rod het weer links en regs taper gate waardeur tie rod ends vas skroef met tie rods wat na die wiele toe gaan. Om terug te kom oor jou vraag, en dit is oor die balljoint van die pitman arm, die beskik nie oor die nodige swing of anders gestel, sywaardse beweging van die joint homself nie. Doen die proef en neem 'n tie rod end en jy sal merk dat dat die joints 'n baie goeie swing het. Neem 'n KZ se pitman arm en probeer daardie balljoint swing. Hy het 'n baie baie beperkte swing. Nou hoe operate hierdie joint [waar swing 'n vereiste is] na die oorkantste knuckle arm ?.

[Mud Dog]

OK, nou verstaan ek waaroor jy praat. Moet net sê dat ek nie bewus is dat die KZ se pitman van die ander verskil nie, maar as dit wel so is dan moet die KZ se steering box (of liewer pitman arm) nie vir so 'n conversion gebruik word nie.

[Mr_B]

I guess the answer, when using the KZTE steering box, is to either get the correct pitman arm, or have the pitman arm engineered to remove the ball and accept an external ball joint.

I also wasn't aware that the KZ box differs from the others, here's what I found on the web:

What must be the KZ style box:

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A IFS box like I've seen:

And a IFS box with modified pitman arm to accept a rose joint above, probably the best option:

[doppies]

Ok, now we agree on that point, fit a suitable pitman arm as you show to do the job 100%. I just raise this matter to make people aware of smal tech points on conversions to be missed and end up in a smash. What i did i use the orginal pitman, relay bar and idler arm as it is on theIFS. I fit a tie rod end as it is on the IFS nearest to the pitman arm and linked to the far knuckle arm. (left side)The benefit of the tie rod end is that you have unlimmited movement, actuaully 360 degrees.

[doppies]

May be it is also important to say I do away with leaf springs and fit Landy ciol springs and control arms with a panardrod(anti sway bar) I make sure every moving part clear and work very nice. The project is not totally finish on other aspects like engine conversion and cab modifications. If I am finished, I will post some pics.

[Mr_B]

Willem please post some pics, sounds very interesting!