Basically Koni makes three types of dampers:
- Twin tube hydraulic (Reds and STR.T/Orange)
- Low pressure gas (Yellows)
- Frequency selective damping (Special ACTIVE)
Reds have been around the longest, and are twin tube hydraulic dampers that are adjustable outside the car. So you pick your adjustment setting and forget it. On full soft, the Reds provide a ride slightly firmer than new stock dampers and offer improved handling. They lack the harshness I find on gas-pressurized dampers like the Bilstein TCs and, to a lesser extent, the OE Sachs dampers.
Koni STR.T dampers are designed to offer Koni quality and a lifetime warranty in a lower-priced unit. They are twin tube hydraulic, not adjustable, and set to provide more damping than Reds on full soft. They are designed to work with lowering springs, and provide enough rebound damping to work well in those applications.
Yellows are low-pressure gas dampers that, depending on the vehicle, are adjustable when in the car. For Volkswagen MKIV models and newer, low-pressure gas damping is limited to the front units, while the rears utilize a hydraulic design that cannot be adjusted while installed. This is because the tops of the rear dampers aren’t accessible from inside the car, like they are in MKIII and earlier VWs. Yellows on full soft are significantly firmer than Reds on full soft, and on their firmest setting are quite firm. Both Reds and Yellows, like most street dampers, are adjustable only on rebound. Compression damping adjustment is only available on some higher end coilover setups.
Koni’s Special ACTIVE dampers are the newest line and the updated version of the FSD(Gold) line. They incorporate what they call Frequency Selective Damping in their struts, while the rear shocks are low-pressure gas and not adjustable. The FSD technology provides the Special ACTIVEs with soft damping on high amplitude movement, such as potholes and expansion joints, and firm damping on low amplitude movement, such as cornering transitions.
This provides a strut that rides well on bad roads and handles well when you want to drive aggressively. We find Special ACTIVEs work the best with stock height springs and you should look towards other lines if you are interested in lowering the vehicle or drastically raising it.
Real World Applications
Those are the basic differences. Here are some general application thoughts based on real world use and feedback from the community.
Koni Reds work best with stock springs and wheels. They are not ideal for very aggressive driving, but they provide a responsive feel with limited body roll while still maintaining a comfortable ride. They tend to struggle somewhat with heavier wheel and tire setups or upgraded brakes, as the added weight can overwhelm the damping. They can also work with lowering springs when adjusted toward the firmer side.
STR.Ts are generally considered firmer than Reds on the softest setting and offer stronger rebound damping than Bilstein TCs while maintaining good ride quality. Because they are hydraulic rather than gas-pressurized, they tend to feel better over rough surfaces. They work particularly well on cars with firmer factory spring rates (Beetles), as well as setups with larger wheels, upgraded brakes, or mild lowering springs.
Koni Yellows offer an excellent balance between ride quality and handling for aggressive street driving or occasional track use. Their adjustability allows the ride to remain comfortable on softer settings while significantly improving handling when dialed firmer. They pair especially well with performance-oriented spring setups and are a strong choice for enthusiasts who want versatility.
If you want strong handling without sacrificing comfort, the Special ACTIVES paired with stock springs are an excellent option. They provide impressive ride quality while still improving body control and responsiveness. They handle most road conditions exceptionally well and do a great job compensating for the limitations of the MKIV suspension design. While they are less suited to very heavy wheel and brake combinations or aggressive lowering setups, they remain one of the best overall choices for a daily driven car.
To summarize:
- STR.T: Lowest cost, firm damping
- Red: Closest to OE ride with improved handling
- Yellow: Firmer damping with adjustability, best for larger wheels and brakes
- Special ACTIVES: Best ride quality with excellent handling
Hopefully this helps narrow down the options rather than complicating them further. Diesel on!
We stock a variety of KONI shocks & struts available for VW/Audi, Mercedes, Jeep CRD, Sprinter models and more! Whether you’re looking for a complete lift kit or trying to decide what type of ride you’d like, IDParts.com is your source for tried & true dampers by KONI.
