A control arm silent block wears quietly until the moment it doesn’t: a knock appears in the steering, the front end wanders on the motorway, tyre wear becomes uneven. Rubber silent blocks on city roads last six to twelve months; on village roads or in road salt contact, even less. A driver in Khmelnytskyi looking for polyurethane silent blocks has made the right engineering decision: polyurethane lasts 3-5 times longer than rubber, retains geometry in frost, and does not degrade in oil. This article explains what silent blocks are, why polyurethane outperforms rubber and NBR in numbers, and how to order them for your vehicle.
What Silent Blocks Are and What They Do
A silent block (suspension bushing) is a rubber-metal element consisting of an outer metal sleeve, an inner metal sleeve, and an elastic layer between them. The silent block is pressed into the control arm eye and connects the arm to the subframe or body, allowing the arm to rotate in one plane while absorbing vibration, noise, and minor misalignments of the parts.
The silent block absorbs road impacts and prevents them from reaching the body: all the force going through the suspension arm first passes through the elastic layer of the silent block, which is dissipated as heat rather than transferred to the structure. At the same time, the silent block must maintain the geometry of the arm: excessive play in the worn elastic layer causes the arm to shift and the steering to lose precision.
The balance between these two requirements — absorbing impact and holding geometry — is determined by the hardness and mechanical properties of the elastic material. Rubber in factory silent blocks is selected for the smoothest ride. Polyurethane is selected when longer life and better handling precision are the priorities. The product range of suspension elastomers is in the catalogue.
Why Polyurethane Silent Blocks Outperform Rubber and NBR
The mechanical difference between polyurethane and rubber is most clearly seen in the numbers from standard tests. The table compares the three main materials used in silent blocks.
| Material | Abrasion DIN 53516, mm³ | Operating t, °C | Tensile strength, MPa | Tear resistance, kN/m | Shore hardness | Oil resistance |
|---|---|---|---|---|---|---|
| Polyurethane TIMOL | 38-39 | -60…+100 | 39-87 | 40-120 | 85A-95A | excellent |
| NBR rubber | 80-150 | -30…+100 | 10-25 | 10-50 | 40A - 90A | good |
| SBR rubber | 100-200 | -40…+80 | 8-20 | 8-35 | 40A - 80A | poor |
The key numbers for a silent block are tear resistance and tensile strength: they determine whether the elastic layer holds up under a hard road impact. Polyurethane tear resistance of 40-120 kN/m versus 10-50 kN/m for NBR means the polyurethane layer is 2-3 times more resistant to tearing at the bond between material and metal sleeve. This is where rubber silent blocks fail first: the layer peels from the inner sleeve, play develops, and the arm geometry is lost.
Abrasion tells the second part of the story: polyurethane wears 4-7 times more slowly than rubber, so even under constant micro-movement in the bushing seat the material does not thin out and does not lose its damping properties. The operating range to -60 °C means that in Khmelnytskyi’s winters the silent blocks do not harden and do not cause the knock-on-cold characteristic of rubber that has lost elasticity in frost. And unlike SBR, polyurethane is oil-resistant: road petroleum products and de-icing salts do not degrade it.
Engineer’s tip: when installing polyurethane silent blocks, tighten the control arm mounting bolts with the vehicle on the ground with suspension loaded, not on the lift. If you tighten the bolts with the arm hanging in the air, the silent block elastic layer will be permanently twisted in the pre-stressed position and will pre-wear at the bond with the sleeve. On the ground the arm is in the neutral working position, and the bolt torque fixes the silent block in the geometry the engineer intended.
Hardness Selection for Your Driving Style
Polyurethane silent block hardness is set at the casting stage from 50 Shore A to 70 Shore D. This range covers everything from nearly stock ride quality to sport suspension stiffness.
For a passenger car on city and regional roads with an everyday driving style, a Shore A hardness in the middle of the range is optimal: the ride quality is close to factory rubber, handling is noticeably more precise, and service life is 3-5 times longer. The transition to polyurethane is felt as slightly more direct steering feedback and cleaner body control in corners.
For sport driving or a vehicle with a constant load — a van, pickup, SUV — a harder formulation closer to Shore D is appropriate. The arm geometry is held with minimum play, the suspension response to steering input is more direct, and the greater elastic layer stiffness is compensated by the shock absorbers rather than the silent blocks. This is the configuration chosen for track days and heavy-load operation.
The third scenario is restoration after damage. If the arm has been repaired after impact and the geometry of the silent block seat has changed slightly, a harder formulation compensates for minor clearance changes and delays the repeat appearance of play. In all cases, the optimal hardness is agreed with the factory technologist based on the vehicle model and operating conditions.
Where to Buy Polyurethane Silent Blocks in Khmelnytskyi
Khmelnytskyi is one of the western-Ukrainian industrial cities where agricultural and transport equipment is heavily used — exactly the conditions where polyurethane silent blocks pay back the fastest, because seasonal field operation in dust, moisture, and road reagents destroys rubber in one season. TIMOL factory ships to Khmelnytskyi from Dnipro by Nova Poshta or Ukrposhta typically within one to two days.
The factory produces silent blocks by diameter and bore from the vehicle model data or from the measurements of the worn part. Both standard stabiliser and arm bushings and industrial silent blocks for agricultural and transport machinery are manufactured. To place an order, supply the vehicle make and model (or the worn part dimensions), and specify the desired hardness. For consultation and ordering, contact TIMOL factory. Engineers will select the optimal formulation and arrange production and delivery to Khmelnytskyi.