Revolutionise
Your Ride
We offer a range of urethanes with different hardnesses and
properties. They provide the development engineer the following benefits
over rubber and give superior mechanical charasteristics over cold cured
and injection moulded urethanes:
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A longer working life, three to four times that of rubber |
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Impervious to petrol and vehicle oil |
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High resilience, the ability and speed of returning back to its original
shape |
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Low compression set and so an excellent resistance to permanent deformation |
Why use Polyurethane for your suspension
requirements?
Polyurethane is an ideal material for making
into suspension bushes. Its combination of high tensile strength and elasticity
translates into immense durability in the toughest conditions. It has excellent
relilience, springing back in to shape effortlessly to absorb shock and
prevent dirt ingress and wear. Lastly, it doesn't age or perish - rubber
both perishes and is attacked by oils and fuels.
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Anti Roll Bar Bushes
You need the relilience of polyurethane to ensure a tight fit
to the bar. This avoids knock and squeaks from loose bushes and
minimises wear. The "Touring" grade is best for this,
but the "Performance" grade is best if you want to reduce
body roll and sharpen up steering. |
Control Arm Bushes
Polyurethane's elasticity allows control arms to move as intended
whilst its tensile strength soaks up punishment from cornering,
braking, accelerating and poor road surfaces. Go for a "Touring" grade
bush to preserve ride quality for longer, or choose the harder
"Performance" grade to improve body control and steering. |
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Spring Bushes
Spring bushes are subject to the same forces as a control arm
bush, as well as supporting the weight of the vehicle. Polybushes,
with their combination of strength and elasticity, improve bush
life and ride quality in on. |
Shock Bushes
Shock bushes can crush down leaving the shock to rattle on its
mountings. Polyurethane's relilience counters this without needing
as hard a bush, so you can specify the
"Touring" grade for all but the most arduous applications. |
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Mounting Bushes
All the vehicle's moving components cause noise and vibration
so Polybush make a range of mounting bushes for steering, suspension,
engines and transmissions. The polyurethane isolates these unwanted
buzzes and rattles, but holds the components firmly in place improving
ride smoothness and body control. |
We Solve Your Problems!
If you are a design and development engineer for vehicle
suspension parts, we can solve your problems with a material that overcomes
the following drawbacks of rubber suspension parts:
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A too high wear rate |
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The high cost of tooling and prototypes |
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The long lead time for prototypes |
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The wearing away of mating metal parts |
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The deterioration due to the effects of petrol and oil |
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Poor relilience especially at high hardness |
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Poor load bearing and low tensile strength |
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High copmression set causing permanent deformation |
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High temperatures generating by the working bush leading to failure. |
Mercedes Buses
The Mercedes 309-814 and Vario range of buses are the
workhorse of the First Bus, Stagecoach and Arriva bus fleets.
The constant stop-start regime, poor roads and speed
bumps cause havoc to their van derived suspensions. High bush wear leads
directly to the bus not being out earning money.
For over 10 years we have been supplying the after sales
market with Polybush link, spring eye, anti-roll bar clamp and shock absorber
bushes for this range of buses. Our specially designed link bush is shown
below:
These link bushes trialed at Travel West
Midlands and First Bus PMT exceeded 50,000 miles of 12 months and still
did not need replacing. This compared exceptionally well with the 6 - 8
weeks and 6,000 miles that they used to get with rubber bushes.
Click
here for a comparison of common elastomers and more information on polyurethane
Proves Long Working Life
A European bus manufacturer was looking
for a link bush that would offer the ultimate performance and longevity.
Using the Millbrook Proving Ground in Bedfordshire, they compared
standard rubber bushes with:
The tests were repetitive +/- 80mm anti-roll bar movement
cycles on a fixed test bed plus ride comparisons on a road vehicle.
The results were:
- The rubber bushes failed after 5,000 to 15,000 cycles
- Our Polybushes lasted 55,000 cycles
- Our Polybushes were measured at 10 - 15 degrees celcius cooler
than the rubber bush while operating on the test bed
- Our polybushes did not change the ride of the vehicle
Bonaprene Products are now a supplier of a range of Polybush parts
to European bus manufacturers. |
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Compression Deflection Tests
A customer asked us to compare samples taken from
a problem suspension bush with two possible Polybush alternatives.
The customer's bush was permanently compressing under load and
then splitting radially.
The samles were compressed at 30mm per minute to
50% of their original thickness and relaxed at the same rate. This
cycle was repeated without interruption over 20 cycles.
The actual force and reduction in force between
the first and last cycle were:
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Max
force
1st cycle |
Max
force
last cycle |
Force
loss |
| Polybush 65 °A |
1644
N |
1614 N |
1.8% |
| Polybush 75 °A |
2756 N |
2656 N |
3.6% |
| Original rubber bush65 °A |
1912 N |
1700 N |
11.1% |
The table shows how quickly the rubber permanently
compresses compared to the equivalent hardness of Polybush. Once
in this state, the rubber's resilience and ability to flex is geatly
reduced causing splitting and failure. |
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