Crossover steering question

[argonaut]

Some thoughts on the subject of crossover vs factory steering setups:

Both crossover setups and factory setups apply a moment to the steering knuckle, regardless of the direction of travel of the drag link. So I don't see how either system can really have more bump steer than the other, simply due to one style vs the other. To me it has more to do with the relative lengths, and range of motion, of the linkages.

On the crossover steering kit I installed, the lever arm is actually longer (further from the ball joints / steering axis) on the crossover steering arm than a factory steering arm. This means that for a similar pitman lever arm length, there is less torque required at the steering box to apply a moment to the knuckles. However it also means that for a given rotation of the tire, it gives a larger input back to the steering gearbox. I suspect this is what would cause some people to feel that highway steering dynamics had been compromised by the crossover.

Crossover steering exerts a component force that wants to push and pull the axle from side to side with respect to the frame. Conventional factory steering exerts a component for that wants to push and pull the left side of the axle forward and backward along the frame. These two systems have different effects on the chassis and suspension components, namely the frame and the leaf springs.

The length of the crossover drag link is much longer that the factory drag link so total working angle on the crossover link should be less. However, if you look at the ratio of length change of the drag link vs the associated suspension linkage in the plane parallel to the ground, as wilkin250r did above, there may not be much difference between the two.

I think that it is hard to have a general discussion like this about crossover vs non. The steering characteristics of different setup are also largely affected by: caster angle, trail, scrub radius, lever arm lengths, etc. And all of these are affected by tire diameter, width and wheel offset, which most "offroad" trucks have working against them.

I personally chose to use a crossover steering system because at the that time in my build I was planning on lots of suspension travel and the crossover seemed to give better working angle for the linkages over a wider range of suspension motion. Also, my F*ord Bronco uses a crossover setup from the factory and it has worked well for me without any crazy bumpsteer or death wobble characteristics that keep me from driving it daily.

I do agree with Larry that there is a lot of (internet discussion driven) hype about some upgrades such as the crossover steering. Also keep in mind that people selling the kit, like it or not, are in the business to make money. So it should be a surprise that the usefulness of the kit might be slightly overly optimistic when described to the customer.