In today’s world of crossovers, the idea of a taught handling experience seems to have been lost in exchange for practicality and versatility. Although Mazda has entered into the crossover market with the CX line of vehicles, they haven’t forgotten their sports car heritage when designing it. Japanese tuning company Autoexe has taken notice of Mazda’s noble effort, and in a bid to capture the hearts of sports car enthusiasts with a crossover, they’ve developed a healthy line of parts for the CX-5. 

In this article, we’ll be installing a set of Autoexe coilovers for the KE CX-5. The CX-5 we’ll be using for this article is one of our customer’s vehicles, and has already been fitted with an array of other Autoexe parts such as the front strut tower bar, lower arm bars (front and rear) and the premium tail muffler. As the car is about to hit 60,000 miles, it served as a good time to replace the dampers from wear and tear to maintain optimal driving performance. 

Please note that this is not a full install guide, rather this is designed to show the features of this product. 

The Autoexe coilover kit includes front and rear dampers as well as the springs and a set of two spanner wrenches. This kit is designed to provide you with a comfortable ride while providing heightened agility over the factory suspension. These coilovers are height adjustable via the perch, however the compression and rebound is set from the factory. 

Before we started, we took a measurement of the front and rear ride height. On the front, we noted a height of 32” and 33” on the rear with the stock suspension. We opted for a mild drop on both axles; by default, autoexe’s coilover kit lowers the car by 15mm (0.59”) on both axles.

The CX-5’s suspension setup consists of a Macpherson strut in the front with a multi-link trailing arm setup in the rear. In order to replace worn components, our customer provided us with a bag of all-new OEM parts, which also saved us time from having to swap over parts from the old suspension. 

Once we jacked the car up and removed the wheels, we took a closer look at the stock suspension with approx. 60k miles on it: 

Both front and rear dampers are gas pressurized to prevent the shock oil from foaming, which can cause cavitation. At this mileage, damper performance has noticeably degraded, affecting ride and overall handling. 

Autoexe’s coilover kit for the CX-5 uses twin tube dampers for both axles, a smart choice for this car. By going to a twin tube setup compared to a monotube, the stroke length can be lengthened without physically extending the casing of the damper, as the outer (pressure) chamber surrounds the working (inner) chamber. By opting for a long stroke length, a comfortable ride can still be achieved, keeping true with the CX-5’s original intentions. Furthermore, if the damper casing is dented from some sort of impact, the piston can move freely as the pressure chamber will take the brunt of the hit as it hits on the outside. 

We used Motul Tech Grease 300 to ease installation on certain parts such as the bump stop. 

After compressing the spring over the factory top mount, we were able to get it back installed into the car:

Ideally, you’d want to opt for adjustable sway bar end links, as the angle of the sway bar has changed due to the lowered ride height of the car, adding pre-load to the bar. In addition, adjustment of tie rods to compensate for the new height is recommended to avoid bump steer. Adjustable end links and tie rods are both available for this car from Autoexe; we will hopefully be doing an install of both on this car in the near future. 

To save time and a headache, the upper bolts for the rear dampers are studs, eliminating the need to rip apart any liners in the trunk to access the top bolts; simply undo the nuts at the bottom of the studs. The bottom shock joint on our customer’s CX-5 was attached via a very long stud; you can either choose to remove the stud to get the damper off (not recommended) or to slide it off the stud by putting leverage on the suspension arms. 

We adjusted the height of the rear suspension by spinning the upper perch mount’s collars, in order to lower the rears more than the fronts. The upper and lower spring seats were changed for new ones, however the upper shock mount for the rear dampers was re-used.

After everything was properly torqued down, we checked the height on the new settings, which showed a new height of 31.5” in the front and 31” in the rear, as opposed to 32” and 33” on the rear. Doing a before and after test of the handling showed that the new suspension provided greater control compared to the worn out factory dampers, while the use of rubber factory mounts eliminates any noise problems associated with harder mounts. 

For more Mazda CX-5 and Auto-exe, bookmark our blog for more content! We will be installing the Autoexe tie rods and end links in a separate article when our parts arrive. 

If we look at the car as a whole, it can be likened to the human body, with each component having a similar equivalent to a body part. As we’ve discussed in previous articles, the chassis acts as the skeleton of the car; by following this example, parts such such as control arms and suspension linkage act as the car’s limbs. Much like human limbs, the joints on control arms and suspension require something to prevent friction. For humans, we have cartilage at our joints, whereas vehicles use bushings.

Suspension bushings are small, round parts placed at the joints of your car’s suspension components. Bushings come in a wide variety of types in materials to suit different use cases. As insignificant as they may seem, these small little devices find importance in your car’s suspension due to the sheer amount of them used. The ND Mazda Miata, which uses double wishbones in the front and multi-link suspension in the rear has over 30 bushings. By swapping out all of these bushings, one can imagine the change it will bring. 

In the case of passenger cars such as the Honda Civic and Toyota Corolla, the factory bushings are designed to provide low cost, durability and comfort. These bushings usually consist of an inner and outer sleeve with a large rubber inner insert; the insert helps absorb vibration and noise that would otherwise be transmitted to the cabin. Under most driving conditions, rubber bushings are the best choice; unfortunately, the rubber rigidity which is ideal for most production cars falls short when placed into a performance driving scenario.

Bushing Deflection - What Is It?

Bushing deflection is what occurs when the material in a bushing (rubber in this case) is deformed due to external forces. If you’ve ever rubbed an eraser too hard and noticed it bending one way and another, you’ve experienced what bushings go through when overloaded. Suspension geometry and alignment is only effective if the components do not move or change position. Bushing deflection occurs when cornering loads force the inner sleeve to move out of the center as the rubber compresses on one side. Due to the vast number of bushings in varying places, the effects it can have on handling are significant.

Bushing Deflection And Camber 

A tire can only exert its full cornering force if the contact patch is making full contact with the road surface. When vehicles with independent suspension are faced with bushing deflection,. the front control arms will move in relation to the frame. When the control arm is forced to move, the wheel is forced to move with it, causing the camber value to become positive. When the rear camber value changes on a rear-wheel drive car with an inexperienced driver at the wheel, the loss in traction can cause oversteer. 

Bushing Deflection’s Effects On Steering And Toe

The steering linkage on your car uses rigid links and joints, resulting in very little deflection when exposed to high cornering forces. Due to the bushings used for the control arms, deflection can cause the arms to move while the linkage stays in place. When the deflection occurs, the steering angle changes even if the driver holds the steering wheel steady, resulting in “twitchy” steering. 

The effect caused in the steering of the car via deflection varies on the placement of the steering linkage in relation to the steering knuckle. Deflection Understeer occurs when the linkage sits in front of the knuckle and causes the tire to turn less than what the driver asks. Deflection Oversteer occurs when the linkage sits behind the knuckle and causes the wheel to turn more than what the driver asks. Deflection oversteer is generally considered to be safer and thus the linkage position is behind the knuckle in most modern cars. 

A wheel’s toe angle can have a direct effect on a car’s handling, for better or worse based on the situation. In the past, Porsche’s use of a Weissach Axle on the 928 reduced oversteer by having the toe adjust itself mid-corner. The Weissach Axle was essentially a modified version of a semi-trailing arm suspension setup; the front pivot bushing from the trailing arm was replaced by a short link, which causes the rear wheel to toe in as the load on the wheel increases, acting as if the car had four wheel steering. 

On the 2nd generation (FC) Mazda RX-7, a special bushing that was designed to deflect after forces of 0.4G or higher acted on it was used. The end goal of this was to have a similar effect as the Weissach Axle while using a traditional semi-trailing arm layout. This special bushing only allowed the deflection to let the car toe inward. In other cars with trailing arm and semi-trailing arm rear suspension, bushing deflection will cause the toe to move inward when power is applied, while braking the toe moves outward. With an inexperienced driver at the wheel, the toe’s instability is detrimental to driver confidence and the overall driving experience. 

Replacing Your Factory Bushings - Choosing The Right One For You

Even though bushings are a wear item, their replacement is largely ignored by many drivers. The rubber used in the bushing can wear from driving wear and tear as well as weather changes and old age. If you’re looking to change out your bushings either due to wear or to reduce/eliminate deflection, it’s important to choose the right type 

Installing factory rubber bushings will provide those looking to restore comfort, noise and handling to factory levels with the solution they need if they are not looking for performance. This is the best choice for most drivers. 

On the other hand, aftermarket rubber bushings usually use rubber with a higher durometer (hardness) than your factory bushings. These bushings are less prone to deflections but still keep many of the advantages associated with rubber bushings including low cost, vibration/motion absorption and low noise. 

Urethane bushings are a popular solution for drivers looking to eliminate deflection due to their cost and stiffness, however these aren’t perfect. It is a common misconception that urethane bushings work in a manner akin to that of a hard rubber bushing, however that is not the case. Due to the nature of suspension joints moving, a bushing must be able to allow movement, usually in the form of rotation. With rubber bushings, the soft nature of the material allows a bushing to twist under load. Due to this deformation occurring in the rubber itself, there is no need for the bushing to be lubricated. 

Urethane Bushings are so stiff that they technically work as bearings, so a sliding motion must be allowed on the inner surface. As a result, Urethane bushings require frequent greasing to provide smooth operation. One the grease wears out, the urethane begins to bind to the metal surface, causing squeaks and knocks as the suspension moves. Eventually the urethane will stick to the suspension joints, causing them not to operate correctly. Some bushings have an inner sleeve which have grease retention channels to cut down on maintenance intervals, however periodic lubrication is still required. 

Steel Bushings operate similarly to urethane bushings - they are essentially bearings, and require periodic greasing in order to work properly. Steel bushings do not have any deflections, however NVH is sharply increased. These bushings are used in some race cars where noise and vibration is not a concern. 

Nylon Bushings are more expensive than Urethane bushings and they require periodic lubrication, however these far outlast rubber bushings, with many lasting upwards of 100,000 miles. When the outer sleeve is fitted with a zerk fitting, you can easily lubricate the bushings without having to constantly disassemble control arms.

Provided that your new bushings allow for rotation without binding, you will not see much of a difference in ride quality. To keep the parts moving freely, many of the solutions described above must be greased when necessary to allow for the necessary motion. The main noticeable difference is the increase in road noise being transmitted to the cabin. To many, benefits from the increased performance of harder bushings far outweigh the negatives, but ultimately the choice is yours. Solid Bushings are available from Legsport while hardened rubber bushings are available from Autoexe on our online store.