Since seeing MR RIZK‘s post about ‘Hope for Castor” (https://my350z.com/forum/showthread....6#post2159726), that question has been nagging me.

Why would we want to reduce the Castor on the Z?

I like the weight of the Z’s steering wheel. It’s not as talkative as an Elises’s, but still pretty well balanced. A have a pretty good idea of what’s happening at the front tires contact patches.

Reducing Castor will reduce the effort at the wheel at the cost of a loss of feed-back. If it’s one thing I want, it’s MORE feed back. I’d go as heavy a steering as I can!

So, the only reason I see why someone would like less castor would be to lighten the steering, to help during transitions on an AutoXs tight track?

 

I agree with you, I dont see any reason to run less castor.

 

Castor = oil used to treat constipation.

Caster = one of the three primary wheel alignments.


Sorry, just couldn't resist. After seeing MR RIZK's post it just been driving me crazy.

 

Depends or who you're reading.

Caroll Smith uses Castor in his books.

Just like the Brits say Tyre and not Tire.

 

hehehe
caster not only alleviates steering feel.
if you have less caster the car may tend to track easier.

caster also affects camber in turn in
the more caster the more camber.

(correct me if i am wrong someone)

 

You are correct! More Castur( ) will increase the cambur gain curve when the wheel is turned. Castur is usually measured by reading the change in cambur when turning the wheels 20 degrees left, then 20 degrees right. (D*mn, I wish I had a tiny o on my keyboard!)

 

Here is all I know:
Caster is the angle of the steering axis at the front of the car when viewed from the side. More caster increases the self-centering effect of the steering, but also increases tire scrub slightly while cornering. Different caster angles on the left and right side causes the steering to pull in one direction. Using the factory-recommended caster angle is preferred.

 

heavy steering does not mean you have good steering feedback. feedback is a measure of how well you can tell what the front tires are doing, when you can literally feel the surface and undulations in the road through the steering wheel. a miata takes a lot less effort than a z to turn the wheel but i don't think the z's feedback is any better.

 

I agree that heavier does not mean better. But a light steering from a large mechanical advantage and plenty of castor and one other with little mechanical advantage and virtually non existing castor will have some pretty different behavior!

I’ll take the larger castor one, with as much scrub radius I can muscle through a race event.

You have to keep in mind a Spec Miata runs on 205 tires where most track driven Z in this discussion will run 255+ tires. The SM is lighter in every aspect.