A shock absorber only damps motion and the spring is mounted separately. A strut is a damper that is also a structural part of the suspension and carries the spring. A coilover is a damper with the coil spring mounted around it, usually on a threaded body so you can set ride height, and often with adjustable damping. Coilovers can replace either struts or shock-and-spring setups, and they change how the car rides and handles, not just how it looks.
Coilovers vs struts vs shocks
| Shock | Strut | Coilover | |
|---|---|---|---|
| Job | Damping only | Damping plus structural support | Damping with an integrated spring |
| Spring | Separate | Mounted on the strut | Mounted around the damper |
| Ride height | Fixed | Fixed (factory springs) | Usually adjustable |
| Damping adjustment | Rare | Rare | Common |
| Typical use | Factory replacement | Factory replacement | Lowering and handling upgrades |
What a strut does that a shock does not
On a MacPherson strut suspension the strut locates the wheel and sets part of the alignment, so its top mount carries the weight of the car. That is why a car with struts needs an alignment after they are replaced. Coilovers for strut cars take over the same structural role, which is one reason quality matters.
When coilovers make sense
- You want to lower the car by a set, adjustable amount, or set corner weights for track use.
- You want to adjust the balance between comfort and body control with damping adjustment.
- Your factory struts are worn and you were going to replace them anyway.
When struts are the better choice
- You want factory ride height and ride quality on a daily driver.
- You drive rough roads where a lower car scrapes, or you carry heavy loads.
- You do not want to revisit ride height, alignment and damping settings.
Ride quality and setup
Coilovers usually ship with stiffer springs than stock, so expect a firmer ride. Lowering too far reduces suspension travel and can cause bottoming and tire rub. After installing them, set ride height evenly side to side, torque everything with the car on its wheels where the instructions call for it, and get an alignment. If you only want a modest drop with the factory dampers, compare coilovers vs lowering springs; for the basics, see what are coilovers?
Coilovers we list
The BC Racing BR Series Coilovers for Subaru models ($1,195.00) and the lower BR Series Extreme Low Coilovers ($1,345.00) cover Subaru applications; the BR Series Evo X Coilovers ($1,195.00) fit the 2008 to 2015 Evo X. Check each listing for your model, year, spring rates and adjustment range. For the platforms, see Subaru WRX and STI parts and Mitsubishi Evo parts.
More guides: how long coilovers last · BC Racing BR vs Extreme Low.
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