Sorry wasn’t meaning to say the mounting point on the knuckle changed scrub, what I was getting at was the steering will change with his movement forward without moving the rack as well. The increase in the radius from center to outer tre means the rack (horizontal throw) won’t match as well as it did with less of a radius. So the steering angles are all going to be fucked off and pronounced.I don't know a whole lot about these upgraded racks, but I also want to look into something stronger once I increase tire size. I've already gone through a few racks, and I know larger tires will only make it worse.
On the Howe racks, is it full hydro with the servo built in, or is it actually a rack and pinion with hydro assist? I can't really tell. Sounds really expensive too.
Those Sweet racks look like there is some potential in there. Are they supposed to be pretty strong? I can't really tell the differences between them. All I could tell was width and travel (at least that's what I'm assuming the measurements are). I'd like to look more into these. I'm sure it wouldn't be hard to fab up some bracket to mount those.
That last idea of using a slider rack and swing setup could be an idea too. Less packaging space than a steering box. especially for you guys with the rack between the crossmembers up front. Mine is behind the crossmember, so I could potentially make room for a steering box. Would be fairly easy to add hydro assist down the line (which is probably what we really need when playing in the rocks).
Moving the rack doesn't effect scrub radius at all. Scrub radius is measured through the upper and lower ball joints and its relation to the tire contact patch. Unless you are talking about scrub in another term that I don't know of. It can mess up the ackerman a little, but bump steer is the big one.
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(Why when building a swing steering matching the swing arms arc to knuckle arc helps improve feel and handling) I mean any rack will experience this but making the arc bigger like he did will pronounce it unless addressed elsewhere.