Scrub Radius

How does it translate to road feel?

I know what caster/camber/toe, SAI do, but I read it somewhere on here that if the SAI intersects with the centerline of the wheel, roadfeel, even on a setup with no power steering, is next to nothing.

Can someone take this concept apart for me?

If you provide good answers then I'll ask y'all for the top 5 trouble spots on a 1964 Buick Riviera. LOL!

iam prety good with angles but i am not sure what you are asking sai is not adjustable on its own its a combo of the three adjustable angles it can be afected while the others are in spec by wear on suspension or impact damage what is your objective and what car and have you changed the suspension

iam prety good with angles but i am not sure what you are asking sai is not adjustable on its own its a combo of the three adjustable angles it can be afected while the others are in spec by wear on suspension or impact damage what is your objective and what car and have you changed the suspension


I found some websites that explain it in a nutshell:

Zero scrub radius = video game steering wheel with no feedback.

Positive Scrub radius = Increased steering effort(the way I like!), maximum road feel BUT most kickback from bumps, bump steer, and leading to one side with braking. (Performance sedans, sport coupes).

Negative = some road feel but minimizes kickback and pull to one side when braking. (most econoboxes today)

It is effected by vehicle height and rim selection.

Are you talking about the difference between the center of the wheel and the steering axis?

Are you talking about the difference between the center of the wheel and the steering axis?


If that ain't scrub radius then I don't know what is. LOLOL!

Seriously though, I'm on a mission here to find out why cars with seemingly similar suspensions/alignment specs, etc, can have completely day/night handling traits. And I've come to realize that it's more complex than just "de-boosting power steering" or "adding more caster" or designing more SAI into a suspension.

But as indicated in my second post, the sites that I went to pretty much summed up the different types of s.r. and their effects on road feel and handling.

A good handler is a combination(sometimes compromise) between certain alignment specs and a well-tuned power steering system and decent rack.

Now for the next great mystery: The chicken or the egg, or, caster vs sai: which should I build more of into my design? (Again, I know what they do, and what happens to one of them in reverse, and wha-hoppens to the other at low speeds - so I don't need much of a primer there!)