12:05 Garage- ’70 Duster build
It can indeed be that simple....
Lets see????.....he (DionR) made two changes. He added some re-enforcing (should have zero effect on wandering) and offset bushings (my read is to add more caster...why else?) and started experiencing the car wondering.....IMO, a classic case of bump steer.
From my 50 year old memory (mid 70's) reading and applying the Mopar Performance Chassis manual I remembered "blueprinting" our front ends to reduce toe changes thru suspension travel on our drag cars by changing the location (up / down and in / out) of the steering arm / tie rod end pivot........ which just happens to be one of the effects of adding caster. FYI, as the top of the spindle tilts further rearward (adding caster), the end of the steering arms moves downward respectively. Most that add (a significant amount) caster NEVER even consider the change in front end geometry.
I'm just trying to point to a solution to a problem he might not have considered.
He had +7° caster on one side and +1° on the other. It wasn't bump steer, he had a shopping cart wheel on one side.
And yes, changing the location of the end of the steering arm can alter your toe change curve. But when you're adding caster with eccentrics you're never just changing a
single spec. So, it's not a given that you're always adding bump steer by adding caster, you're not making a single change so it's not simple. It depends on ALL of the other alignment specs, in addition to the ride height. Adding negative camber can change the bump steer, lowering the car the can absolutely change the bump steer, changing the bump stop heights can change the bump steer curves because you're altering the angles on the upper and lower control arms and the steering arms by changing the travel range, etc.
Most people that buy $5k coil over conversions don't actually spec out the changes in front end geometry either, they just go on advertising. Doesn't make it right, doesn't mean it doesn't work either.
Bump steer is pretty obvious when you're driving a car, and it doesn't just result in "wandering". If everyone that added positive caster had lousy bump steer, someone would have noticed it by now. I certainly haven't noticed a significant change in bump steer in my own car, and I run +6.5° of caster. But my car is also lowered 2", had the bump stop heights altered, runs tubular LCA's and double adjustable UCA's. Every single one of those things altered the toe change through the suspension travel, and yet somehow my car isn't a bump steer nightmare.
Hey mate i am fitting the exact same belts to mine as engineer requires it due to the 6.4 swap. With the standard drop do you find it sits nice on the shoulder or wants to ride up? Love the build have read pretty much the entire build thread haha
The belt sits on my shoulder well, doesn't ride up. It's an 8" drop on the shoulder belt. The Procar seats sit up a bit taller than the factory buckets though.
