Polyurethane Rods

Whiteline polyurethane rods are solid, machinable lengths of polyurethane for making your own bushes, spacers, isolators and mounts. When an original part is no longer made, or a custom build needs a component no kit can supply, polyurethane rod gives you a tough, durable material to shape exactly what you need.

The range offers a choice of diameters, from smaller rods suited to spacers and sleeves through to larger rods for substantial bushes and mounts. It suits workshops, fabricators, restorers and motorsport builders who need dependable material for one-off and short-run parts.

What Polyurethane Rods Are Used For

Polyurethane rod is a versatile starting point for components that need to cushion, locate or isolate while resisting wear. Common automotive uses include:

• Custom suspension bushes for rare, classic or discontinued vehicles
• Spacers, packers and shims for suspension and chassis fabrication
• Mount isolators for radiators, exhausts, fuel tanks and body components
• Bump stops and rebound buffers for custom suspension setups
• Grommets, sleeves and wear pads for one-off projects and prototypes

Because you machine each part to size, the rod is ideal when you need a single component, an unusual dimension, or a prototype to test before committing to a production part.

Understanding Rod Size and Hardness

Diameter and Length

Each listing shows the rod?s outside diameter, in millimetres with an inch equivalent, and its length. The rods are solid, so you can drill or bore them to any inside diameter your design needs, and cut them into as many individual parts as the length allows.

Shore Hardness

Hardness for elastomers is measured on the Shore scale, and each rod?s rating is shown on its listing. A lower Shore A number means a softer, more compliant material that absorbs more vibration. A higher number means a firmer material that resists compression and gives more precise control.

For suspension bushes, spacers and isolators, a firm but flexible polyurethane is usually the best choice. It controls movement without transmitting excessive harshness, and it recovers its shape after being compressed.

Polyurethane vs Rubber and Rigid Plastics

Compared with rubber, polyurethane is more resistant to compression set, abrasion, oil and weathering. It holds its shape under load far longer, so custom parts keep their dimensions and performance for longer.

Compared with rigid engineering plastics such as nylon or acetal, polyurethane is elastic. It can absorb shock and vibration and return to its original shape, where rigid plastics would transmit more noise or crack under impact.

This combination of toughness and flexibility is why polyurethane is so widely used for performance suspension bushes. It?s also why rod stock is so useful when you need a custom part.

Machining Polyurethane Rod

Polyurethane can be cut, turned, drilled and bored with common workshop equipment, but it behaves differently from metal or rigid plastic. As a general guide:

• Cutting to length: use a band saw or fine-toothed saw, and support the rod to stop it deflecting.
• Turning: use sharp tools with a positive rake, moderate speeds and light finishing passes. Blunt tools tend to tear the surface rather than cut it.
• Drilling and boring: drill an undersized pilot hole first, then open up the bore gradually with a sharp drill or boring bar.
• Allowing for elasticity: polyurethane compresses slightly under tool pressure and springs back afterwards. Take light final cuts and measure carefully before removing the part.
• Managing heat: keep cutting speeds sensible and clear swarf regularly, as heat build-up can affect surface finish.

For critical parts, machine a test piece first to confirm your settings before cutting the final component.

Designing Custom Bushes and Spacers

A few design principles help custom polyurethane parts perform well:

• Plan for a sleeve. Polyurethane bushes generally pivot on a steel inner sleeve, so allow for one and size the bore to suit.
• Use the right interference. A light interference fit holds the bush securely in its housing without over-compressing the material.
• Add flanges where needed. Flanges control sideways movement and stop the bush walking out of its housing.
• Allow for lubrication. Pivoting surfaces should be greased with a lubricant suitable for polyurethane, and grooves machined into the bore can help retain it.
• Consider wall thickness. Thicker walls give more compliance and comfort, while thinner walls give more precise control.

These rods are intended for automotive and general fabrication. For food-contact, medical or other regulated applications, use a material certified for that specific purpose.

Choosing the Right Rod

Start with the finished outside diameter of your part, including any flange, and choose the next size up so you have enough material to machine a clean finish.

Next, check the hardness rating against what the part needs to do. Firmer material suits parts that locate components precisely. Slightly softer material suits parts that mainly isolate vibration.

Finally, work out how many parts you need and their combined length, plus an allowance for each saw cut, to confirm how many rods to order.

Who Polyurethane Rods Suit

Polyurethane rods suit workshops and fabricators producing custom or replacement parts, and restorers of classic and rare vehicles where original bushes are no longer available. They?re also used by motorsport teams developing prototype or one-off components, and by experienced home builders with access to a lathe and drill press who want to make parts tailored exactly to their project.

Shop Polyurethane Rods

Polyurethane rods belong to our universal parts range, along with polyurethane sheets.

Choose the diameter and hardness that suit your project, order online for delivery, or pick up your rod from an authorised Whiteline reseller. Every Whiteline component is backed by our warranty, a fitment guarantee and 30 day returns. Build custom bushes, spacers and isolators to your exact specification with Whiteline.