Polyurethane Bush Grades Explained
What Do the Different Polybush Grades Mean?
Polyurethane suspension bushes are available in different hardness grades, each designed to deliver a different balance of ride comfort, suspension control and handling performance.
At Polybush, our grades range from 65 Shore A to 85 Shore A, with each formulation selected for a specific type of vehicle and driving application.
The important thing to remember is that harder doesn’t always mean better. The right polyurethane bush hardness depends on your vehicle, its suspension design and how you use it.
For some classic cars and Land Rovers, you may have a choice of Polybush grades, allowing you to tailor the driving characteristics of your vehicle. For many newer vehicles, however, there is no grade choice. We specify the correct material for the application.
Why Can’t I Choose a Grade for My Vehicle?
As vehicles have become heavier, faster and more sophisticated, their suspension systems have also become more precisely engineered.
Modern suspension systems operate with tighter tolerances and are designed around specific levels of compliance and deflection. Using a bush that is too soft could allow excessive movement and affect the way the suspension performs.
Where there is no grade option, we’ve selected the polyurethane material that provides the best balance of performance, durability and comfort for that specific application.
This means you don’t need to choose the hardness yourself — we’ve already specified the grade to suit the vehicle.
Our Polyurethane Bush Grades
Where a choice of grades is available, Polybush offers three main options:
- Comfort – Blue 65A
- Dynamic – Orange 75A
- Performance – Red 85A
The higher the Shore A number, the harder and more resistant to deflection the polyurethane is.
| Grade | Hardness | Main Benefit | Typical Application |
|---|---|---|---|
| Comfort | 65A | Ride comfort and compliance | Classic cars, Land Rovers and everyday driving |
| Dynamic | 75A | Balance of comfort and handling | Fast road and spirited driving |
| Performance | 85A | Maximum control and precision | Performance, track and towing |
Comfort (Blue 65A):
Maximum comfort and suspension articulation
Our Comfort grade polyurethane bushes are manufactured from a 65 Shore A compound and are designed for drivers who prioritise ride quality, refinement and everyday comfort.
The softer polyurethane allows greater suspension articulation and provides a cushioned feel that helps absorb bumps, vibrations and imperfections in the road.
Comfort grade bushes are particularly suited to classic cars and Land Rovers, where maintaining a relaxed, comfortable driving experience is often just as important as improving suspension durability.
They are designed to provide a balance between replacing tired original bushes and retaining the character of a classic’s factory-fresh driving experience.
Choose Comfort 65A if you want:
- A softer, more compliant ride
- Maximum suspension articulation
- Improved absorption of bumps and vibrations
- Reduced road noise
- Comfortable everyday driving
- A more original-style driving experience
65A Comfort is ideal for drivers who value comfort and refinement over outright handling performance.
Dynamic (Orange 75A):
The balance between comfort and performance
Our Dynamic grade polyurethane bushes use a 75 Shore A compound, providing a middle ground between Comfort and Performance.
They are firmer than 65A bushes, reducing suspension deflection and helping improve handling, steering response and cornering control.
At the same time, they retain enough compliance to remain comfortable for regular road use.
Dynamic is particularly well suited to drivers who want a more engaging and responsive driving experience without making their vehicle unnecessarily harsh.
They can also be suitable for spirited road driving and light track use.
Choose Dynamic 75A if you want:
- Improved handling and steering response
- Less suspension deflection
- Better cornering control
- A balance between comfort and performance
- A more engaging driving experience
- Suitability for spirited driving and light track use
75A Dynamic is the ideal choice when you want sharper handling without giving up too much ride comfort.
Performance (RED 85A):
Maximum control and precision
Our Performance grade polyurethane bushes are manufactured from an 85 Shore A compound and are the firmest of our three main grades.
The harder polyurethane minimises bush deflection, helping maintain greater suspension control and precision during hard acceleration, braking and cornering.
Performance grade is designed for enthusiasts who demand the most from their vehicle and is particularly suited to high-performance, competition and track applications.
The increased stiffness can result in a firmer ride, but in return you get greater control, stability and responsiveness when driving the vehicle hard.
Performance grade can also be particularly beneficial in applications where additional suspension control is required, including towing.
Choose Performance 85A if you want:
- Maximum suspension control
- Minimal bush deflection
- Sharper steering and handling response
- Increased stability under hard driving
- Greater precision during cornering
- Performance and track-focused driving
- Additional control for towing applications
85A Performance is designed for drivers who prioritise control and handling over maximum ride comfort.
65A vs 75A vs 85A: Which Polybush Grade Should I Choose?
If your vehicle offers a choice of Polybush grades, the decision comes down to the driving characteristics you want.
Choose 65A Comfort for:
Comfort | Compliance | Everyday driving
Choose Comfort if you want a softer, quieter and more compliant driving experience, particularly for classic cars, Land Rovers and vehicles used primarily on the road.
Choose 75A Dynamic for:
Balance | Handling | Spirited driving
Choose Dynamic if you want to improve steering response and handling while retaining a good level of everyday comfort.
Choose 85A Performance for:
Control | Precision | Performance
Choose Performance if you prioritise maximum suspension control, sharper handling and reduced deflection, particularly for performance, track or towing applications.
Does a Harder Polyurethane Bush Mean Better Performance?
Not necessarily.
A harder polyurethane bush generally allows less deflection, which can improve suspension control and handling response. However, suspension bushes need to provide the correct amount of compliance for the suspension system they are designed for.
Using a bush that is harder than necessary can result in a firmer ride without providing a meaningful benefit.
That’s why we don’t simply recommend the hardest grade available. We specify the material according to the requirements of the vehicle and suspension application.
Why Newer Cars Often Have Harder Bushes
Modern vehicles are significantly different from many classic cars.
As vehicles have become heavier and faster, suspension systems have evolved to handle greater loads while maintaining precise control. Suspension components also operate within increasingly tight tolerances.
This means modern vehicles often require firmer bushes as standard to control suspension movement and maintain the intended geometry and handling characteristics.
For these applications, Polybush selects the appropriate material rather than offering an unnecessary choice of hardness grades.
What Is Machinable Polyurethane?
In addition to our standard polyurethane bush grades, Polybush also produces machinable polyurethane material.
This material is manufactured at 90 Shore A hardness, allowing it to be machined on a lathe.
Machinable polyurethane is used where a component needs to be produced or modified through machining rather than moulding. It provides the hardness and machinability required for specialist applications.
Find the Right Polyurethane Bush for Your Vehicle
Whether you’re restoring a classic car, improving the handling of a Land Rover or upgrading a modern performance vehicle, choosing the correct polyurethane bush grade is important.
Where a choice is available, you can select the grade that best matches your priorities:
65A Comfort → 75A Dynamic → 85A Performance
Where there’s no choice, we’ve already selected the polyurethane formulation appropriate for your vehicle.
If you’re unsure which Polybush grade is right for your application, check your vehicle’s available options or contact our team for advice.
Frequently Asked Questions
What is the difference between 65A, 75A and 85A polyurethane bushes?
The main difference is hardness. 65A is the softest, providing greater compliance and comfort; 75A provides a balance between comfort and handling; and 85A is the hardest, providing maximum resistance to deflection and suspension control.
Are harder polyurethane bushes better?
Not necessarily. The correct hardness depends on the vehicle and application. A harder bush can improve control and reduce deflection, but an unnecessarily hard bush can make the ride harsher without providing additional benefit.
Which polyurethane bush grade is best for a classic car?
For many classic cars, 65A Comfort can provide a good balance of improved durability and a comfortable, original-style driving experience. Where available, 75A Dynamic or 85A Performance may be preferred by owners looking for sharper handling.
Which Polybush grade is best for a Land Rover?
Land Rovers may have different grade options depending on the specific application. 65A Comfort is suited to owners prioritising ride comfort and articulation, while firmer grades can provide increased suspension control. Always check the grades available for your specific application.
Why don’t newer cars have a choice of Polybush grades?
Modern vehicles generally have tighter suspension tolerances and are designed around specific levels of bush compliance. As vehicles have become heavier and faster, firmer bushes are often required to control suspension movement. Where there is no choice, Polybush specifies the appropriate material for the application.
What does Shore A mean?
Shore A is a measurement used to describe the hardness of materials such as polyurethane and rubber. A higher Shore A number indicates a harder material. Polybush’s main grades range from 65A Comfort to 85A Performance.
