More automakers going with fiberglass springs

Audi is the latest automaker to announce a move to coil springs made of fiberglass. Actually, Tier One suppliers have been investigating fiber springs for awhile now. Expect to see more developments in this area.

Audi is in the news this week because it plans to start using suspension springs made of glass fiber-reinforced polymer (GFRP) in one of its cars before the end of the year. Audi says it developed the spring in collaboration with an Italian supplier.

As you might suspect, lower unsprung weight was the reason Audi made the move. Audi says a steel spring for an upper mid-size model weighs nearly 2.7 kg (6.0 lb), while the plastic equivalent weighs 1.6 kg (3.5 lb). Thus the four springs going into the new Audi will cut its weight by roughly 4.4 kg (9.7 lb), half of which pertains to the unsprung mass.

Audi says the core of the springs consists of long glass fibers twisted together and impregnated with epoxy resin. A machine wraps additional fibers around this core — which is only a few millimeters in diameter — at alternating angles of ± 45° degrees to the longitudinal axis. These tension and compression plies mutually support one another. In the last production step, the blank is cured in an oven at temperatures of over 100°C.

Audi says the GFRP springs can be precisely tuned to their respective task. The plastic doesn't corrode, even after stone chipping, nor is it sensitive to chemicals such as wheel cleaners. And production requires far less energy than the production of steel springs.

Of course, Audi isn't the only car maker planning to use plastic springs. Here is what Ford told us about its plastic springs back in January at the Detroit Auto Show:

And two years ago, ZF was showing MacPherson struts made from plastic:


Discuss this Blog Entry 3

Cookijar (not verified)
on Jul 11, 2014

GM has been using fiberglass springs on its Corvette for eons. Our 1991 Chev Lumina and Pontiac Grade Prix both had fiberglass springs.

on Jan 3, 2015

Your Chev Lumina and Pontiac Grade Prix really very great and powerful)))

on Jan 2, 2015

Audi on a diet, fiberglass springs? Car manufacturers are coming up with some crazy crazy crazy ideas. Springs made with fiberglass strands, coated with resin, and baked in an oven! Ding! Ding! Ding! Springs are ready! Fiberglass does Not corrode, chemicals do Not affect them, lighter weight, a more fuel efficient car, and springs can be designed for different applications.
**You will never know unless you try. See how they last after a year or so and test the ones that fail. Springs can break, whether it's steel or fiberglass.
*Some 'Real World' driving is required......
**Less vehicle weight, less fuel used, higher fuel prices at the pump. Big Oil will make a profit and you will pay, pay, pay. **Putz!! bwaaa ha ha ha !...
Drive vehicles with high mpg, are very safe, reliable, have a ‘reasonable’ cost and a good ‘value’ for the money.
The price of fuel at the pump is too high!

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