All About of the KPI

All About of the KPI , everything you know/ don `t know and were afraid to ask , without registration and fee.

What is a KPI?

At this angle between of an imaginary axis passing through the point of attachment to the knuckle

and plane drawn through the midpoints of the wheel. All these imaginary axis and the plane you

can see in the figure.

But these lines by itself mean nothing. Really on the car's behavior influences – SCRUB RADIUS.

That depends on where this two lines cross cross each other in relation to the ground .

In total, there are 3 different options:

 

 To achieve perfect handling of the chassis in the corners you need zero SCRUB RADIUS. As in real

car your chassis need some KPI because it is impossible to put upper point of attachment between

knuckle and arm inside the weel. Thus KPI - it's not a super secret setting for real drifters it is just

technological necessity.

And finally, not to be confused with CAMBER and KPI. KPI depends from construction of

knuckle/C-hub. Meanwhile CAMBER depends on length of upper arm. If I lost in words just

take a look to picture below.

(Foto fom Re-Extreme Blog)

 

Why you chassis need a KPI?

The ability to adjust the KPIs needed:

• If you put the wheels with large offset (increase SCRUB RADIUS)

• If you like for some reason to ride with a large CAMBER (increase SCRUB RADIUS)

tilting the axis passing through wheel

 

 

If you have large clearance and bump CAMBER.

 

 

How to adjust a KPI?

KPI Setting is only possible if the proposed design your knuckle or C- hubs.

 

To set KPI change location of ball-connectors on upper and lower surfaces of you knuckle, if you use

C-hubs only upper ball- connector. Typically, the manufacturers indicate which degree

will have a KPI angle at different positions of the fixing points.

But forget about figures itselfs. Remember you need to reach zero SCRUB RADIUS. 

Look at your chassis from the front. And imagine two lines we talk about.

If the lines crossing on ground point – your reach the goal. If not try to change something.

If two line crossing inside of weel – you have some SCRUB RADIUS. If outside of weel – you have

too much “Posicam” which even worse than SCRUB RADIUS.

Have fun. And keep slide.