Whatever Happened to Fibreglass Coil Springs
Whatever Happened to Fibreglass Coil Springs
Whatever Happened to Fibreglass Coil Springs
Whatever Happened to Fibreglass Coil Springs?
The Forgotten Suspension Revolution That Never Quite Took Over
The motor industry has always been driven by innovation. Every decade seems to bring another breakthrough that promises to transform the cars we drive. Some inventions change the industry forever, while others quietly fade into history despite showing enormous promise.
Many motorists remember the arrival of fuel injection, anti-lock braking systems, airbags, satellite navigation and, more recently, hybrid and electric vehicles. Yet there are other developments that generated great excitement within the motor trade but somehow disappeared almost as quickly as they arrived.
One such example is the fibreglass reinforced plastic (FRP) coil spring.
Here at Pellon Tyres in Halifax, I can clearly remember these unusual suspension springs appearing several years ago. In fact, when I mentioned them recently to some of the staff, they looked at me as though I had imagined the whole thing. Yet they certainly existed, and at one stage many engineers believed they could replace conventional steel suspension springs on millions of vehicles.
So what happened?
The humble coil spring: Whatever Happened to Fibreglass Coil Springs
Every car relies on its suspension system to keep the tyres firmly planted on the road whilst giving occupants a comfortable ride.
Without suspension springs every bump would be transferred directly into the bodywork, making driving uncomfortable and difficult to control.
The modern steel coil spring has been refined over many decades. It is remarkably strong, relatively inexpensive to manufacture and capable of surviving hundreds of thousands of compression cycles during its lifetime.
Despite these strengths, engineers have always searched for something even better.
The problem with steel
Although steel is incredibly durable, it has a number of disadvantages.
Firstly, it is heavy.
Every kilogram removed from a vehicle helps improve fuel economy, handling and emissions. Manufacturers spend millions of pounds trying to save just a few kilograms from each new model.
Steel also corrodes.
Here in Yorkshire, where winter road salt is used extensively across the Pennines, we regularly see suspension springs rusting before eventually snapping. Many motorists around Halifax, Sowerby Bridge, Hebden Bridge and the surrounding Calderdale villages have experienced the unpleasant surprise of discovering a broken spring during an MOT inspection.
As garage owners we became very familiar with replacing steel springs.
Then along came a fascinating alternative.
Sogefi enters the picture: Whatever Happened to Fibreglass Coil Springs
Italian engineering company Sogefi, already well respected for manufacturing suspension components and filtration products, began developing something very different.
Instead of producing springs from hardened steel, engineers experimented with fibreglass reinforced plastic, often referred to simply as FRP.
Rather than winding steel wire into a coil, these springs were manufactured using thousands of glass fibres bonded together with advanced resin technology.
At first glance they looked almost too unusual to be taken seriously.
Yet behind their strange appearance lay some remarkable engineering.
Much lighter than steel
The biggest advantage was weight.
These composite springs weighed approximately 40 to 70 per cent less than conventional steel springs depending upon the application.
That may not sound much, but engineers become very excited whenever weight can be removed from the suspension.
Suspension components belong to what engineers call unsprung weight.
Reducing unsprung weight allows the wheels to react more quickly to bumps and uneven road surfaces.
The result can be:
- Better ride comfort.
- Improved road holding.
- Sharper steering response.
- Reduced vibration.
- Lower fuel consumption.
Every vehicle manufacturer was looking for these improvements.
They didn’t rust: Whatever Happened to Fibreglass Coil Springs
From the point of view of garages like ours, another enormous advantage immediately stood out.
Composite springs simply didn’t rust.
Anyone who has worked beneath British cars for many years knows exactly how harsh our climate can be.
Road salt, damp winters and endless wet weather eventually attack almost every steel suspension spring.
Composite materials solved this problem almost overnight.
That alone made them a fascinating proposition.
Audi leads the way
It was Audi that became one of the first major manufacturers to introduce FRP coil springs into production.
Working alongside Sogefi, the company fitted them to selected high-performance models.
The engineering world was impressed.
Trade magazines predicted that many other manufacturers would soon follow.
At the time it genuinely appeared that steel springs might gradually disappear.
I remember them arriving: Whatever Happened to Fibreglass Coil Springs
After spending most of my working life in the tyre and motor trade, you naturally remember unusual developments.
I clearly remember these springs being discussed throughout the industry.
They certainly looked different.
Compared with conventional steel, they almost appeared futuristic.
At Pellon Tyres we fitted some during repairs, and it was obvious that somebody had invested years of research into producing them.
Fast forward several years, and I recently mentioned them to the lads in the workshop.
Their response?
“You must have dreamed them!”
Well, I can assure everyone that I wasn’t dreaming.
Why didn’t they become the future?
This is perhaps the most interesting question of all.
The technology worked.
The springs were lighter.
They resisted corrosion.
They reduced vehicle weight.
So why don’t we see them everywhere today?
The answer is probably a combination of factors.
Manufacturing costs: Whatever Happened to Fibreglass Coil Springs
Composite manufacturing remained considerably more expensive than producing traditional steel springs.
Car manufacturers always work within strict budgets.
Saving weight is important, but only if the financial case also stacks up.
Steel continued improving.
Steel spring technology did not stand still.
Metallurgy continued advancing, making modern springs stronger, lighter and more durable than ever before.
The gap between steel and composite became smaller.
Electric vehicles changed priorities.
Within only a few years the entire industry became focused upon electrification.
Manufacturers invested billions into batteries, electric motors, charging systems and software.
Composite suspension springs became just one of many technologies competing for investment.
Lessons from history: Whatever Happened to Fibreglass Coil Springs
The story reminds me of many innovations throughout my years in the motor trade.
Some ideas transform the industry forever.
Others arrive slightly ahead of their time.
Remember when everyone predicted:
- Rotary engines would replace piston engines.
- Run-flat tyres would become standard on every vehicle.
- Hydrogen would dominate road transport.
- Wet timing belts would revolutionise engine design.
Some succeeded.
Some partly succeeded.
Others quietly faded away.
The fibreglass spring belongs firmly in that second category.
The future may not be over
Interestingly, composite materials continue to develop.
Carbon fibre, advanced plastics and lightweight alloys are now used extensively throughout modern vehicle production.
As electric vehicles continue evolving, reducing weight remains one of the biggest engineering challenges.
That means the idea behind composite suspension springs may yet return in another form.
Sometimes technology simply waits for the right moment.
Yorkshire roads still demand good suspension. Whatever Happened to Fibreglass Coil Springs
Whether your car uses steel springs or advanced composite materials, the purpose remains exactly the same.
Around Halifax, Calderdale and the Pennine hills, suspension works extremely hard.
Potholes, uneven road surfaces, steep gradients and constantly changing weather all place tremendous strain upon springs, dampers and suspension joints.
That is why regular inspections remain so important.
At Pellon Tyres we frequently inspect suspension components during servicing, wheel alignment and MOT testing.
Broken springs remain one of the most common faults we discover, particularly after harsh winters.
Looking back
After nearly sixty years in the motor trade, one of the pleasures is remembering developments that younger mechanics have never encountered.
The Sogefi FRP coil spring is certainly one of them.
It represented bold thinking.
It challenged accepted engineering practice.
Although it never replaced conventional steel springs on a large scale, it proved that engineers are constantly searching for better solutions.
Perhaps one day a new generation of composite suspension components will once again appear on our roads.
If they do, I shall probably smile and say,
“I’ve seen something very similar before.”
After all, motoring history has a wonderful habit of repeating itself.