ackerman angle

Hi guys.
Im doing my Datsun units currently. I got the dimension from the balljoint to the tie-rod at 6.5 inches. Plus the tie-rod connection is offset .500 inches from center.This is on the new steering arm. Am I safe?
Picking up the spacer blocks up this week. Then all I have left is the Strange shocks to purchase.

How does this Ackerman ratio come into play?
Thanks.
Al

Ackerman, as I understand it comes into play round tracking. It's the ability of the left tire to turn in more on corner entry. Leads the right front tire some.

Maybe some body else will chime in.

http://www.auto-ware.com/setup/ack_rac.htm

Check this out.

Yea, going around a corner the Ackerman geometry makes the inside tire turn a little tighter turn than the outside tire. Everything I have read shows just like Blake's link that the "ideal" distance back where the imaginary lines drawn through each side's lower ball joint/spherical joint & steering arm tie-rod/rod-end should cross each other is at the rear axle.

But even if the two imaginary lines don't cross at a distance back dead nuts perfect at the rear axle, just being in the general area of the rear axle is still better than having no Ackerman at all.

Ackerman is only true for low speed turning, at higher speeds trye slip angle and dynamic weight transfer have a greater influence.
Modern circuit racing thinking is to run no ackerman or anti-ackerman, depending on the cars requirements. Makes low speed parking type manuevures hard work though.
A lot of modern road cars run "modified ackerman" which displaces the intersection point by up to + or - 30% of the cars wheelbase.

Short answer, don't sweat it.

I wont then, Thanks.
Al

I have to disagree......

He's building a drag car and a decent amount of slow speed turning does come into play just maneuvering around the pits & making the sharp turn from the front of the staging lanes to the burnout box at some tracks.

And in faster drag cars your already having to fight 8* to 10* of built in positive caster when you try to turn the wheel to go around a corner. Why increase the turning effort by having to fight tire scrub from little/no Ackerman. Plus if a drag car gets loose & sideways during the pass the last thing you want is to push, scrub, or slide the narrow front runners while trying to correct.

Ackerman is built into drag struts for a reason. Lamb, Santhuff, & Strange wouldn't go to the effort of designing it in if it wasn't needed/useful on a drag car.

WHOOPS!,
Good point Dave. Looks like I "WILL" check that out, since my setup is custom. Dont want any surprises.

BTW also,Thanks for the info Blake.
Regards.
Al

Good points.

If I remember this week I will take a pic of a Strange sportsman strut steering arm & post it.

Thanks Dave.
You da man.

Regards.
Al

It's not as much angle as say a Mustang II spindle's steering arm, but there's definitely some angle there.