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16 May 2024
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Advice Blog
What are suspension bushes and what do they do:
Suspension bushes are pieces of material, generally rubber that are fitted where the suspension arms are bolted to the chassis. Along with the springs and shock absorbers, they dampen Noise, Vibration and Harshness NVH picked up from the roads. So, why fit Polybush?
A rubber bush, even from new, that is identical in shape, size and material hardness to Polybush, will, during braking and cornering, deflect and deform even more than it’s Polyurethane counterpart, changing your suspension alignment.
Polybush’s longer-chain chemical bonds give greater strength which resists this movement and requires more force to move. This is due to its high Young’s modulus (which is a mechanical property) meaning that your alignment is kept in check, maximising grip.
Enhanced Performance Around Corners and Under Braking: Polybush vs. Rubber
What this means in real life, is with rubber bushes, when you turn into a corner in your Fiesta Mk6 the suspension will flex excessively, causing the inside wheel to have play, (Toe changes) thus, compromising grip. (Camber changes) This can be felt as soft or “laggy” steering in tight/fast corners.
Polybush’s resistance to deflection keeps your alignment intact and your wheels true to your intended path. This translates to improved stability, precise steering control, and enhanced confidence behind the wheel, especially during aggressive cornering and braking…
Like track days, or B-road blasts. This can be seen in the diagram below showing the Mk6 wishbone fitted with Polybush and its alignment maintained
In the next diagram, which compares diagrams 1 & 2 from a side angle, we can see how the Grey Rubber bush has distorted from its centreline (CL) compared to the Red Polybush at the top, changing the toe angle and camber.
Understanding Camber & Toe: The Keys to Handling Performance
Camber refers to the angle of the wheel against a vertical point. Too much negative camber can lead to uneven tyre wear, (inner side of the tyre) whilst positive camber reduces grip. Toe, on the other hand, refers to the angle of the front wheels pointing towards the centre of the vehicle. Both camber and toe are crucial for optimal handling and tyre wear. With Polybush resisting alignment changing forces, cornering and braking, you will maintain those angles. So you’ll experience consistent camber and toe settings, meaning maximum grip and minimal tyre wear.
Compression Set: A Rubber Bush’s Achilles’ Heel, Deterioration Over Time.
Compression set happens when a material is strained beyond its elastic limit, to its plastic limit, leading to permanent deformation. Rubber bushes, have shorter chemical chains, and are prone to compression set, resulting in sagging, ovalisation, and reduced resistance to movement over time. This introduces play into your suspension which permanently deteriorates handling and reduces steering responsiveness.
In comparison, Polybush’s long-chain polyurethane composition resists compression set, providing consistent support and performance throughout your Fiesta’s lifespan.
Why Polybush is Your Mk6’s Best Friend: The Bag Analogy
Imagine the Rubber bushes on your Fiesta’s suspension system as plastic shopping bags. When you pull the bag lightly, it springs back – that’s elasticity. But when you pull it forcefully, it stretches beyond repair – that’s plasticity. Rubber bushes behave similarly, succumbing to this sort of deformation over time.
However, Polybush, manufactured from resilient Polyurethane, maintains shape and structure, ensuring consistent performance and controlled movement over a long time.
The Downfall of Rubber: Degrading with Oil, Fuel and More
Aside from their excess flex and submission to compression set, rubber bushes have ANOTHER fatal flaw; they degrade and break down when exposed to oil, fuel, and other vehicular contaminants. This degradation accelerates wear and tear, hugely compromising driving dynamics and requiring frequent replacement. Polybush’s immunity to oil and fuel means your Mk6’s suspension remains unaffected, ensuring longevity and reliable performance under chemical attack.
Longevity: The key feature of Polyurethane Suspension Bushings
Polybush’s durability is unmatched. Unlike rubber, which degrades over time, Polyurethane maintains its structural integrity, resilience, and performance throughout its lifespan.
With Polybush, you’ll enjoy years of enhanced driving dynamics, reduced maintenance, and peace of mind knowing your Fiesta is equipped for the road ahead.
Debunking Misconceptions About Polyurethane:
Despite its numerous benefits, Polybush has often been subject to misconceptions within the car community. One common one is that all Polyurethane Bushes are Polybush.
Anyone can make Polyurethane bushes, but only WE can make Polybushes.
Another myth to be busted is that “Polybushes” always give a harsher ride compared to rubber ones. Although in some cases this can be correct, generally Polybush products are designed to strike the balance between comfort and performance, as Polybushes are Made In The UK and can be made in any hardness we like, from rubber-band soft to golf ball hard. So you can have improved handling without compromising ride quality – Unless you specifically ask for a Race bush.
Another misconception is that Polybush is difficult to install or requires special tools. On the contrary, Polybush is designed for straightforward installation. Many of our installs take less than two minutes, making it accessible to enthusiasts of all skill levels. With simple hand tools and a bit of patience, you can upgrade your Fiesta Mk6 with Polybush in no time, unlocking its full potential on the road or track – See the Polybush Youtube videos for proof!
The Versatility of Polybush Across Various Applications:
One of the most compelling characteristics of Polybush is its versatility across a multitude of applications.
We’re not JUST about performance, our products can also be used to address various MOT failures commonly encountered by enthusiasts. From worn-out exhaust bushes to deteriorated engine & diff mounts, Polybush provides reliable solutions to ensure your vehicle passes its MOT with flying colours, allowing you to focus on enjoying the thrill of driving without unnecessary worries or setbacks.
Whether you’re driving a Ford KA or a mile-munching Mondeo Mk4, Polybush offers tailored solutions to address specific suspension needs. Our best-selling part is the rear beam bush for the Fiesta Mk7, demonstrating the versatility and effectiveness of Polybush in real-world applications.
Polybush isn’t just limited to car suspension components; Our products are on most buses, they’re on diggers & tractors, quarrying and rock crushing machines, concrete beam manufacturers, industrial rollers for steel mills, recycling and paper mills, we make parts for road sweeper scrapers, quarry equipment, machinery wheels, the list goes on and on.
