USAC Racing Forum

General Chat => Point .25 => Topic started by: Doug Adams on August 30, 2009, 01:54:07 PM



Title: Spring thoughts at the end of Summer
Post by: Doug Adams on August 30, 2009, 01:54:07 PM
I am trying to develop a better understanding of how spring changes effect handling.  Any thoughts that the group can provide would be appreciated.  In evaluating what a spring change does to handling, I would prefer to assume that all other static variables remain constant e.g. ride heights, corner/cross weights, tire pressures etc.  Corner by corner, side to side, front to rear, what does an increase/decrease do to handling (loose/tight, side bite, forward bite, tire temps etc), and in which part of the turn, entry, apex, exit?

As an example, if I increase/decrease the spring rate on the right sides (or the left sides, fronts, rears) of the car it does....

Or if I increase/decrease a single spring rate on the right rear (or LR, or LF or RF) it does....

Appreciate the help


Title: Re: Spring thoughts at the end of Summer
Post by: Doug Adams on September 03, 2009, 04:03:10 AM
As a followup, do these spring tuning guidelines make sense? 

Weaker LF will make the car tight.

Weaker RR will make the car tight.

Weaker RF will make the car loose.

Weaker LR will make the car loose.

Stiffer RF will make the car tight.

Stiffer LR will make the car tight.

Stiffer LF will make the car loose.

Stiffer RR will make the car loose.

Overall stiffer front springs will make the car tight.

Overall stiffer rear springs will make the car loose.

Overall weaker front springs will make the car loose.

Overall weaker rear springs will make the car tight.

If the guidelines do make sense, how might you use one option over another to address a loose or tight condition for different parts of the corner (if relevant)?  For example, the legend above indicates you could loosen up a car by:

Weaker RF
Weaker LR
Stiffer LF
Stiffer RR
Overall stiffer rear
Overall weaker front

How does Front/Rear and Left/Right spring stagger play into the equation?

Could you also apply the same guidelines for ride heights (weaker-lower, stiffer-higher)

Appreciate any help.


Title: Re: Spring thoughts at the end of Summer
Post by: Doug Adams on September 11, 2009, 11:52:13 AM
Is it a mystery to everyone else as well?


Title: Re: Spring thoughts at the end of Summer
Post by: goffin20 on September 11, 2009, 12:55:36 PM
Pick Cory's brain at Advance Shocks and your chassis builder, they will all explain things to you and may even disagree on some things so take alot of notes, do your own testing and then come up with your opinion.

My experience has been

Softer spring/shock package = tighter car
Stiffer spring/shock package = looser car

Cory is very good at giving you spring and shock recomendations based on a particular track, then you can fine tune for other tracks from there, thats what we did.  Unless you have money then you can buy the exact shock and spring recomendations for each track and fine tune based on weather and track conditions. ;-)