Many of our clients would like to know why our catalogue contains two versions of some items intended for the same purpose that look very different. We’ll try to explain.
The polyurethane is not bonded to the inner metal sleeve, so separation from the metal is impossible
In producing polyurethane parts, we try to take maximum advantage of polyurethane’s qualities that exceed those of rubber. This results in a product that looks different from the original but is superior in many ways, particularly in terms of its service life.
In silent blocks with a press-fit inner metal sleeve (“press-fit” silent blocks for short), there is no bond between the material and the inner fitting. Therefore, separation from the inner fitting is impossible, and separation from the outer fitting virtually never occurs due to the significantly reduced load.
The material’s different properties mean a different design
Polyurethane’s high wear resistance allows the material to move freely relative to the metal sleeve without noticeable damage from friction with the metal.
Rubber’s properties, particularly its low wear resistance, do not allow the original part manufacturers to use that design approach, because even high-quality rubber wears quickly and the part would fail.
The press-fit process
Why do these parts have an appearance that differs from the original parts?
1) «Press-fit» silent blocks are usually made of a more rigid material and therefore are of a different colour Like our other products with a Shore hardness of 80, they are green.
2) To prevent possible longitudinal movement of the outer sleeve together with the polyurethane layer relative to the inner metal sleeve (because in this version the polyurethane is not bonded to the inner sleeve), an additional layer of polyurethane is added to lock the part in place (without, however, preventing it from rotating). – Doesn’t the absence of a bond with the inner fitting cause squeaking?
There is no connection with the internal fittings, but a creak will appear, right?
As for the problem of squeaks, polyurethane’s excellent resistance to aggressive media, particularly petroleum products, allows a variety of lubricants to be used when installing the parts.
Whereas grease degrades rubber, it has no negative impact on polyurethane. On the contrary, it helps the material slide against metal, thus extending a part’s service life.
Polyurethane has no problem with grease: the use of a grease reduces noise and squeaking.
Will the grease be squeezed out when the silent block with the pressed sleeve is working?
Thanks to specially designed protrusions, the lubricant is retained in the silent block, and due to the corrugation of the inner surface of the polyurethane, “channels” are created in which a larger amount of lubricant can be accommodated.
You can buy grease in our online store when purchasing auto parts in the section “Auxiliary products for installation”.
If the “pressed-in” silent blocks are so better, why not all the parts have a similar design?
In some cases, operating conditions, loads and seats make it impossible to use the improved design of the silent block – with a pressed-in inner sleeve. Then we produce only one option – a copy of the original.
And in case when the test results and reviews indicate the undeniable advantages of the pressed-in sleeve option, the production of an exact copy of the original is suspended and a transition to the production of an improved analogue takes place.
Polyurethane silent blocks by “Siberian suspension” are ideal for roads in cold regions!
Our own experience and numerous customer reviews allowed us to make changes to the original design of the products. Thus, we tried to solve the main problems associated with the operation of silent blocks reinforced with a metal bushing – separation and creaking. For operation in cold regions, we definitely recommend only such a design option for silent blocks – with a pressed-in, and not welded (as in the original) inner sleeve.
Our competent technical solutions make our products most suitable for operation in the conditions of Siberian roads.