I liberated this pic from another post by 60's Style. On every cross steer setup I've seen,the drag link is not parallel with the tie rod when the wheels are straight. Why is this? Big buck pro built or home built,everyone does it exactly the same. On most applications,there is enough room to move the steering box forward, and the tierod is never further back than when the wheels are straight. Is this a hold over from a packaging problem on the '40 Ford, or is there some other logic involved?
I think it happens for a couple of reasons. One - and I did this one with my 32 - the steering box gets mounted according to the instructions that came with the aftermarket steering box bracket. Two - did this one on the 32 as well - the pitman arm gets bent up for clearance. That makes the arm shorter and the draglink is pulled further back toward the rear. My 32 isn't near as extreme as the pic Unkl posted, but it isn't quite parallel. Practically speaking it doesn't hurt anything. You won't notice it when driving the car. Mounting the steering box - and other components - by making strong tack welds is the best way to go when building a car. Almost always you're gonna want to move something. Especially if it's the first time around for you building a particular style of car. The 31's steering box bracket was tacked in and eventually the location - a little further forward than the 32's - was found to be where I wanted it. The draglink and tie rod are parallel, but the draglink may come back a minute amount if I bend the pitman arm for a little more ground clearance. Speaking of ground clearance, I've seen more than a few cross-steer cars built with the pitman not level and pointing down which made it about the lowest point on the car. Catching the pitman arm on a protrusion of some kind - gas station tank cover etc. - would really tear some stuff up. Better to bend it up and better yet to mount the Vega box as close to level as you can. Here's a pic of the 31 just for the heck of it.
logic? I didn't think it was too critical, my thought was that the arc that the suspension moves through in it's normal action is on a plane more visible from a straight on view then from looking down on it. as one or both wheels travel up and down the distance between the pivot points change on a vertical plane (not horizontal) affecting bump steer. ..it is no more out of parralel than the stock setup.. I suppose looking at the horizontal plane, in the action of steering, the pivot points at the ends of the drag link swinging in opposite arcs would change steering leverage and ratio due to a more acute angle though.. mostly I think I put the box there because that's where the steering wheel felt right with that collumn connected Paul
Well, don't know if it's right or wrong but mine on the Deuce framed 31 Roadster is parrallel from any viewpoint. And it handles like a sports car. My chassis was engineered and built by Brizio, years ago.
When I changed my '31 to cross steer, I made sure everything was parallel to the ground; hairpins, pitman arm, draglink and panard bar. And set the Vega gearbox so that the draglink and tie rod are parallel when the wheels are centered. Mainly because I didn't get any mounting instructions for any of the parts. Just did it so it was logical to me. Front end seems to work just fine. warbird
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