crusty

iTrader: (7)

a friend at the track was having a discussion with me about springs/shocks and he was telling me there should be no preload on the spring of a properly setup car. Was he right or wrong?

wreckya

iTrader: (1)

The only thing the collar on the spring is used for is setting the ride height.

crusty

iTrader: (7)

yes i know mut he was talking about running a tlr 22 2.0 with a ride height of 24mm. he thinks that it should not have a preload on the spring for better handling reasons

Dave H

If I understand correctly, that is wrong, at least for an offroad car.

If the car has no preload sitting at ride height, then the spring will unload as the car jumps, the suspension would be ineffective for a bit on landing. Would require a much stiffer spring to prevent excessive bottoming that would compromise the suspension in the bumps.

The drastic change in spring rate would likely have other weird effects in cornering and bumps I would think. For example when part of the car is lifted by a bump or turn, the other wheels would not have spring force pushing down to force the wheels down in contact with the track. Or for a wheel going over a depression, etc.

Wade....

iTrader: (2)

+1

Lets say it again, all together everyone, "preload is for setting ride height."

When you add preload the spring rate does not change, it is a constant.

Davidka

iTrader: (86)

To add, the amount of preload applied to the spring has no bearing on whether or not it's the correct rate spring.

crusty

iTrader: (7)

what i understood from him is- if a shock is in its full droop position ie unloaded, it shouldnt have a pre load from the spring. Just repeating what he said.
i understand if a car is sitting on the track the springs are obviously under a preload

mtpocketsracing

iTrader: (2)

He clearly does not understand suspension dynamics. Preload is ride height basically. Far more important for real vehicles such as motorcycles.

Dave H

That would limit running softer/lower rate springs that are advantageous in many (most?) situations, while maintaining a proper ride height.

Like everyone is saying, no.

DirkW

iTrader: (1)

+1... as long as we are talking about linear springs, not progressive ones.