What goes into the best 2.5” ID coilover springs for street, track and autocross?

We’ve designed, developed and tested thousands of coilover coil springs over the last three decades. Every coilover shock absorber needs to run the proper coil spring to operate at it’s full potential.

So what are some features to look for when selecting the perfect, performance coil spring for your coilovers?

1. Flat Ground, Square Spring Ends

A high quality coilspring will be manufactured with flat ground ends on both the top and bottom of the coil spring. Why is this important? Flat ground, square spring ends allow for precise fitment and seating when the spring is installed between the coilovers upper and lower coil spring retainers. Flat ground coil springs also prevent wear over time and make adjusting springs and ride-height easier. Flat ground ends offer greater clearance preventing damage to coilover shock bodies which increases the life of your springs and coilover shocks.

2. Coilspring Labeling

Determining a springs rate and length can be done a couple different ways. Some coilover springs are identified by paint code markings located at the top or bottom of the coil-spring. Part numbers can be pad printed or laser etched into the coil springs as well. Many manufacturers will include their logo along with the spring part number or the height and rate of that coil spring. High quality labeling makes it easy to identify the spring as it wears and is used over time.

3. Coilsprings Made in the USA

Coil springs are made all over the world. We prefer coilsprings made here in the USA for several reasons. Many US spring manufacturers have been developing and perfecting their spring technologies for over a century. Through racing, testing and developments in higher strength, lighter weight spring materials – American coilsprings are of some of the highest quality available on the market today.

* A note of caution on select foreign springs – Not all coilsprings are created equal. We’ve seen and tested various coilsprings over the years and have seen first hand some of the low quality springs coming out of China and the poor quality and tolerances. You may be saving a couple bucks, but Chinese made springs vs. USA made springs are night and day. Some of the China springs we’ve tested through our coilover service center have varied up to 30+/- lbs from what was labeled on the spring. We’ve seen cracked springs from low grades of steel and rusted out springs from low quality finishes.

When looking at coilover shocks and coil springs, always ask where the coil-springs are manufactured. Select manufacturers will take a US made coilover and bundle in low quality, foreign made coil springs. Be cautious of chrome coil springs as well from select shock companies. Many chrome coil springs are made of low quality steel overseas and are heavier than chrome coil springs made here in the USA.

Make sure you’re comparing “apples to apples” when shipping for coilsprings. What about coil springs made in Germany? – Good to go. Japan? Select manufacturers – Good to go. China? No. It’s not worth the savings.

Spend the money once and buy a high quality set of made in USA coil springs. Your coilover shocks and your piece of mind will thank you.

4. Spring Finish

High quality coilover coil springs come in many finishes. The best finish we’ve found and use in our springs is a high gloss powder coat spring finish. Powder coat is great because it holds up to dirt and grime and is easy to clean when it comes time. Another finish used by many spring companies and coilover manufacturers is Chrome coil springs. Chrome 2.5 in. ID coil springs are a staple for hot rodders and street rod owners. When looking for chrome coil springs, make sure the spring is cold-wound, high tensile steel. On the chrome finish, look for springs that are chrome plated and baked properly for longer lasting chrome. Chrome requires more maintenance and upkeep that powder coated springs, but when it’s polished out, you cant beat a set of made in the USA chrome coils.

5. Coilspring Material

What is the best material used in coilover springs? Chrome Silicon Steel. Chrome Silicon steel is the latest in spring technology. This steel material holds it’s consistency longer over time and is less prone to bending or twisting under hard cornering and acceleration. Chrome Silicon Steel is lightweight and higher strength than basic types of spring material.

6. Coilspring Tolerances (Higher the Better)

Look for coilsprings that are Cold Wound, Heat Treated and Shot Peened. Cold wound coilsprings are more consistent in regards to spring rate when comparing to hot wound coil springs. Heat-treating is everything. Heat-treating is what makes a certain grade of steel the grade it is. Look for coilsprings that are cold wound and heat-treated. Shot peening coil springs is a process in removing burs, knicks and imperfections on the springs. These processes make for higher quality coilsprings due to the requirement for tighter tolerences through these processes.

7. Coilspring Warranty

Many coilsprings come with guarantees to stay within a certain range over time. A good, high quality coil spring should guarantee that it will stay within it’s original spring rate and free length over time when installed properly and under normal conditions. Again, when looking for high performance, high quality coil springs, choose American.


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