Rubber Engine Mounts vs Polyurethane Engine Mounts

Poly-Tek has been manufacturing the best rubber and polyurethane engine mounts for over 60 years. Rubber and polyurethane are used in many automotive applications because of their excellent reversible elastic deformation properties and excellent damping and energy absorption characteristics. There are advantages and disadvantages between the two types of mounts, which we will discuss below.

What is an Engine Mount?

An engine mount, or motor mount, is responsible for securing and stabilizing an engine.  Using an elastomer-based mount will reduce vibration generated by the motor automobile, creating a smoother and more enjoyable ride for the driver. Also, the mount acts as a spring between the engine and the car body, which reduces the wear and tear on the engine. Moreover, noise from the engine will be reduced. As an engine mount wears out, the amount of vibration felt through the vehicle will begin to increase.

Rubber Engine Mounts – Advantages

• Reduced road Noise
• Dampened vibrations
• Dampened harshness
• No squeaking opportunity
• Lower cost
• Better heat resistance

Rubber Engine Mounts – Disadvantages

• Standard lifespan
• Typical feel of the road
• Standard performance

Rubber’s reputation as a spring material has its origin in its ability to maintain longevity, resilience, bonding to metals, resistance to high temperature, all the while keeping costs low. One significant advantage, rubber has over polyurethane is rubber’s ability to resist heat. If the application includes significant heat resistance, then rubber is the elastomer that should be used. It also resists swelling when under water. Industrial rubber engine mounts are going to offer the greatest vibration and noise dampening effect. However, there are some disadvantages to the rubber style mounts. This type of mount may crack and tear prematurely depending on the amount of ozone added to the rubber compound. This can lead to excessive movement of the engine under larger loads, which in turn means less power is transferred from the engine through the driveline to the rear wheels.

Polyurethane Engine Mounts – Advantages

• Polyurethane will last longer than rubber
• There is an enhanced feel of road
• Enhanced performance

Polyurethane Engine Mounts – Disadvantages

• Increased road noise
• Increased vibrations
• Higher cost
• There is a slight squeaking opportunity
• Less heat resistance

Polyurethane engine mounts provide a compromise between some of the benefits rubber and some of the benefits of solid mounts made of steel. Polyurethane can be compounded for higher durometers than rubber, which will hold the engine in place better than rubber compounded at softer durometers. With a harder material, more energy will be transferred through the driveline. While urethane will increase the vibration felt by the driver because of its increased stiffness. Some of the vibration can depend on the size of the engine, whether the mount is for an industrial truck, car, boat, ATV or other types of vehicle. As with many things, some of the tolerance for vibration by the driver may come down to personal preference. In general, though, polyurethane will be tougher and stiffer than rubber, making it ideal for more highly modified vehicles.


For pricing and quotes on all your motor mount needs please email [email protected] or call 510-895-6001.