Spring Pre-Load

[Birel99]

How does spring pre load effect chassis handling? Lets assume that if we increase pre load in the front that we adjust the ride height so that it did not change.

I assume that increasing preload will see the tires reach their 'optimum' slip angle sooner in the corner? But then reduce grip on the exit of the corner?

Thank you, Birel99

[Jersey Tom]

I assume that increasing preload will see the tires reach their 'optimum' slip angle sooner in the corner? But then reduce grip on the exit of the corner?

How are you coming to this assumption?

Personally I'm not a huge fan of screwing with preload unless you really have a good feel for it and a need. Just another non-linearity you're throwing in.

If you preload one axle, you're basically just putting the majority of the roll stiffness on that axle until you overcome the preload and the springs & bars start moving again.

So, if you were to preload the hell out of the front, I'd expect to have a lot of initial front axle load transfer... and generally numb the on-center / initial turn-in response.

[DaveW]

How does spring pre load effect chassis handling? Lets assume that if we increase pre load in the front that we adjust the ride height so that it did not change.

I assume that increasing preload will see the tires reach their 'optimum' slip angle sooner in the corner? But then reduce grip on the exit of the corner?

Thank you, Birel99

Spring preload, by itself, should make no difference provided stroke is unlimited & suspension geometry is linear.

It can be used to move the static rocker position (by adding preload & then lowering ride height via the pull/push rods. It can also be mis-used to limit available rebound damper travel (i.e. as a droop stop).

Most often (& most sensibly), it is one of the tools (along with packers & bump rubbers) used to set average ride height at one or more nominated airspeeds.

[Birel99]

Thanks for the input. The guy who qualified 2nd in Formula Atlantic at the June Sprints a few weeks ago was pitted right next to me and was talking about preload and he says the more preload you put in (the front) the more initial grip you have. He was extremely quick that weekend. My car is mainly spec and one of the few things we can adjust is pre load...

Thanks,

[Jersey Tom]

Don't believe everything you hear. Especially if there's no reasoning to back it up.

Bottom line, preload is going to affect your initial load transfer characteristics.

[RacingManiac]

besides, each spec car/spec tire series is different...something that might work on one may not work on another...most of those series are about tuning the to the quirk of the car....