(T) Coil springs rubber sleeving at base

Hi there,

Does anyone know the purpose of the rubber sleeving found at the base of many coil springs, including my Uno (different to the plastic coating covering the whole of the spring).

Some say it is to protect the spring at the friction point where it nestles in the suspension cup; others that it wears through after about 1000 miles so isn't that important. Or is it to reduce metal on metal noise as the car travels along? (rubber sleeving has long since perished on my springs).

Since I fitted new rear shocks, I've got a definite 'springy mattress' (!) noise when going over speed bumps so I'm wondering if the sound is coming from the coil springs at the base or is a fault with the shocks themselves? (Can't hear noise when bouncing suspension up and down, only over speed bumps).

Anyone come across this prob before?

Thanks,

Andy

Rubber or plastic coating over springs is to stop sound (usually a springy ringing) that can occur in some cars.
The spring will have a resonant frequency and if you were to hold the car steady on a smooth road those springs will sing.
Its usually only a issue with softer springs found in passenger cars.

Stiff springs will make noise too , but likely out side of the hearing range , or at a very high road speeds where you cant hear them anyway over the other road and engine noises.

Nylon , or rubber spring base pads can help with this sound but their main purpose for being fitted is different.

These pads maximize the surface area that the spring is in contact with its seats.
This spreads the load of the spring across a wear area of the spring base platform.
This in turn reduces friction at this contact point.

Suspension spring and damper performance is improved by a nylon or rubberized spring seat.

BUT - its only needed on certain types of springs and seat shapes.





Racing cars that use coil overs have flattened and machined spring ends and they sit on a flat base.
In that application you would not need a nylon or rubber spring seat.

gW:-)