Front suspension silent bloc guide: a key component of the Renault 5 Alpine and Turbo

A famous little rubber part well known in the automotive world, the silent bloc is also found on the front suspension of the Renault 5 Alpine and Renault 5 Turbo. Often overlooked, it nevertheless plays an essential role in suspension precision and road holding.

Role of the front suspension silent bloc

• Maintaining the suspension geometry: weakness or excessive deformation of the elastomer creates play, which causes unstable road holding.
• Filtrer les vibrations : it dissipates the loads. A rigid mounting would transmit vibrations and stresses directly to the chassis.

Our little front suspension silent bloc endures many loads: acceleration, braking, weight transfer, impacts and wishbone rotation.

Faulty front suspension silent bloc: the symptoms

With all these loads, the silent bloc has a hard life. The elastomer is sensitive to ozone, hydrocarbons and temperature variations.
The rubber dries out and cracks over time.

The symptoms of a worn-out wishbone silent bloc on an R5 are:

un jeu ressenti dans la direction,

• une sensation de flou dans la conduite,
• metallic knocking noises (movement of the centre bush striking the outer bush, or the wishbone contacting the subframe during braking and acceleration).

À vie dure, silent-bloc dur !

Our sports cars, whether Renault 5 Alpine, Alpine Turbo or 5 Turbo, are generally driven hard. The loads are far greater than on an R5 TL. That is why the hardness of the wishbone silent bloc was increased, from around 50 Shore to 70 Shore.

Depuis 2009, Mespiecesauto fabrique de véritables silent-blocs durs en 80 Shore. We have slightly increased the hardness to further improve precision.
Pay attention to the hardness of the silent blocs, as it really determines the behaviour of your car. Also beware of fake hard silent blocs circulating on the market.

Indeed, Renault, for cost reasons, wanted to reuse dimensions already known on its suspensions, but the hardness specification changed.
That is why there are two types of silent blocs: the standard Renault 4 / Renault 5 ones, and the specific hard silent blocs. Our elastomers are laboratory-tested before production of the silent blocs

Shore hardness evolution (50 to 80)

Here is a table showing the difference in rigidity between 50 and 80 Shore:

Attention aux faux silent-blocs durs

Some unscrupulous sellers pass off a standard silent bloc as a hard model. That is why we made a vidéo comparative en 2017 qui reste d’actualité.

Voici quelques effets d’un faux silent-bloc dur de train avant :

• Excessive deformation of the elastomer,
• Rubber separating from its metal substrate,
• Loss of rigidity and dangerous behaviour.

Above: excessive deformation of the silent bloc – elastomer separation

You can even test your parts on receipt.
We made this video comparison, which you can easily reproduce at home:

Besoin de conseils ou d’informations ?

Si vous souhaitez en savoir plus sur les silent-blocs de triangle pour Renault 5 Alpine, R5 Alpine Turbo ou R5 Turbo,
Do not hesitate to nous contacter.