Coilovers: Choosing the Right Ones for Street or Track


Coilovers: Choosing the Right Ones for Street or Track


When it comes to suspension mods, coilovers have long been one of the best upgrades for enthusiasts looking to improve their vehicles’ handling while also bringing some additional adjustability into the mix. Ride height adjustment is an inherent benefit of making the switch from a traditional OE-style shock and spring combination. But as Detroit Speed’s Dan Oddy points out, the advantages of coilovers go deeper than just being able to dial in the stance.

“The ability to adjust the ride height is actually what we’d consider to be the benefit that isn’t really related to performance,” he explains. “That’s more of a visual thing – you can get the car to sit just how you want it to. But on the performance side, the big change is that you’re putting the shock and the spring on the same axis. In some OE suspension setups, the shock and the spring are far apart from each other, and they’re not working together as much as a result.

“Tying them together on the same axis allows both the spring and the shock to work more efficiently because they’re affected the same way by the forces put on the suspension,” continues Oddy. “That provides better handling as well as improved ride quality.” But as evidenced by countless YouTube project videos bemoaning the use of cheap, eBay-sourced hardware, not all coilovers are created equal.

Beyond build quality and tuning precision, the level of adjustability that’s available from today’s coilovers varies widely. As a result, one that’s ideal for a particular application may not be the best option for another. Here Oddy gives us the lowdown on how to choose a coilover for different use cases – whether you’re planning to upgrade your daily driver, hit the autocross course, or put down some hot laps on a fast road course.

ML: These days there are a lot of different coilovers out there at a lot of different price points. From your perspective, what separates a good one from a bad one?

DO: This is one of those situations where you really do get what you pay for. While you might be able to find cheap coilovers that have the features you’re after, there’s going to be a noticeable difference in the quality of the construction and the components used. For example, we use JRi shocks on our coilovers – if you were to look at the internals of those shocks, the machining of the shims, pistons, and other parts are done to an extremely high standard. That approach extends to tolerances and overall manufacturing quality, and the differences are often seen in its performance. When you have better parts and construction, it allows the coilover to respond more precisely – and quicker. When you’re talking about suspension components that have to respond to changes in force in a fraction of a second, quickness definitely matters.

High quality coilovers are also going to have more transparency when it comes to performing as advertised. For example, JRi dynos every shock they send to us, and they include a serialized dyno sheet with it. A lot of companies don’t do that – they might test one out of every 20 they build, or something along those lines, just to make sure they’re in the ballpark.

And on the spring side of things, we have a spring rater here at Detroit Speed that allows us to check to make sure that the spring rate we want is what a particular spring is delivering. And that means the performance is going to be as-expected every single time.

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ML: Does moving from a traditional OE suspension setup to a coilover affect suspension geometry, and if so, how should that be addressed?

DO: It depends on the vehicle, but for the most part these coilovers use the same mounting points as the factory shocks, so there isn’t a lot that needs to be done after the fact to correct the geometry. Changing the ride height by using a drop spring or a coilover will affect it, but it’s generally just a matter of getting a proper alignment for the new setup.

For that reason, we provide new alignment specs with all our kits. That way the caster, camber, and toe are where they need to be for the new stance. Aside from maintaining necessary clearances when lowering a vehicle, that’s really all you need to be concerned with.

ML: Let's take a look at different types of coilovers and where they would work best. For street-focused applications, what should buyers be looking for?

DO: If it’s a vehicle that’s going to spend its time on the street, a non-adjustable coilover probably makes the most sense. This will still allow you to change the vehicle’s ride height to your preference, and of course you’re also getting the benefits of a coilover design as well as shock valving and spring rates that are dialed in for better performance. If a vehicle is going to be used as a daily driver, you might not want to spend the extra money to get a single-adjustable or double-adjustable shock – those features really make more sense in track and competition contexts.

But if the way you use the vehicle changes later on, one of the nice things about our kits is that you can upgrade by just changing out the non-adjustable shocks for single or double-adjustable ones. Same goes for springs – you can swap out a spring for a different rate without changing the shock you’re using with it.

ML: If someone is looking to do autocross events with their vehicle, what type of coilover would you recommend?

DO: This is where I’d recommend going to a single-adjustable coilover. Along with ride height adjustability, a single-adjustable gives you the ability to change the shock’s rebound characteristics. Some of this is driver preference, but road surface also comes into play. Changing the rebound settings alters the amount of force that the shock is using to push the suspension back down onto the pavement after it compresses.

You want to find a setting that’s stiff enough to keep the vehicle’s body motions under control, but not so stiff that it causes the suspension to bounce off bumps rather than absorbing them. You want the maximum amount of the tire’s contact patch connected to the road as often as possible. Having that rebound adjustability allows you to find that sweet spot.

If you’re moving into more competitive autocross with the SCCA, Goodguys, or something else along those lines, you might want to consider stepping up to a double-adjustable coilover. In the case of JRi’s shocks, these double-adjustable units allow you to independently adjust low-speed rebound and high-speed rebound.

These aren’t really for the novice, though. As I mentioned earlier, JRi provides a dyno chart with their shocks, and that provides a lot of useful information if you want to make adjustments. But to really get value out of the additional adjustment capability, you need to have an understanding of how to interpret that information.

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ML: Are there other features that you might want if you’re planning to use the vehicle for track days or competitive road course work?

DO: With road courses, your average speeds are typically a lot higher than they are on an autocross course, and you’re often out on track for 15 minutes or more during a session, rather than a minute or two. Because of those circumstances, a remote canister shock is something you might want to consider.

As the car spends time on track and the shocks warm up internally, the pressure inside the shock body starts to change. The remote canister acts like an accumulator and keeps the amount of pressure in the shock body stabilized by feeding in pressure as it’s needed. And that means the shock’s performance will stay consistent throughout a long session of fast laps.

ML: Given all this information, what’s the best way for folks to zero in on the ideal coilover option for their particular use-case?

DO: The most important thing is to really consider what your goals are with a coilover upgrade and take a realistic assessment of how the vehicle is going to be used. For a lot of people, it’s about having the ability to change the ride height while also improving the vehicle’s handling performance, and a non-adjustable coilover will do that.

But you may also start doing autocross or track days here and there once you’ve had a chance to get comfortable with the car. That’s a situation where a single-adjustable coilover makes a lot of sense. That allows you to start with a coilover that delivers handling improvements as well as the ability to change the vehicle’s ride height right out of the gate, and you’re ready to use it – the rebound adjustment is there.

When you start looking at double-adjustable coilovers, you’re moving into more nuanced territory that can be very useful if you know how to leverage the features properly. Having a set of settings for the street and another set of settings for the track can make a focused performance car easier to live with every day as well as a better performer on the weekends. A driver’s previous experience often helps us determine if a double-adjustable is the right way to go for a particular application.

ML: If someone has other questions about coilovers they're considering, what's the best way to get reliable answers?

DO: Call our tech line or email us – our representatives are incredibly knowledgeable when it comes to this subject. And since we work closely with JRi, if there are questions about shocks that we can’t handle internally, we have additional resources we can utilize to get the answers to any questions you may have.

Call Detroit Speed today: (704) 662-3272

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