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Originally Posted by g6civcx
Bumpsteer can happen regardless of steering angle. If you go straight and hit a bump, it can rip the steering wheel out of your hands and even break your thumb. This is why you are taught to grip the wheel loosely with a relaxed grip.
Bumpsteer happens due to what's called a scrub radius. This is how you measure the scrub radius.
Your Steering Axis Inclination (SAI) is an imaginary line that extends straight down your strut to the ground. From the point where the SAI meets the ground, measure the distance from that point to where the centre of the tyre is. If this distance is positive, you have a positive scrub radius.
A positive scrub radius causes bumpsteer because when you hit a bump and the suspension compresses, the scrub radius allows the bump forces to use the control arm to apply torque to the steering pivot, thus jolting the wheel from your hand. The longer the scrub radius, the worse the bumpsteer because the torque arm will be longer, allowing the bump forces greater mechanical advantage to jolt the wheel.
The way to eliminate bumpsteer is to zero out the scrub radius by making various adjustments to the front suspension, but you are limited to what the factory gave you in most cases.
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Nope.
What you just described is an effect of scrub radius, but that's not bumpsteer. BUmpsteer is what I described above. You described the effects of an increased scrub radius on wheel feedback. But scrub radius isn't really that big of a deal, it does affect rough road tracking and self-aligning torque but doesn't have anything to do with the kinematics of the suspensios whic is what bumpsteer is.