Height Adjustable Lowering Springs and Adaptive Suspension? Pros and Cons

Are you looking for Coilovers or Height Adjustability and at the same time you want to keep your factory Adaptive Suspension option? Height Adjustable Lowering Springs (HAS Kit) offer a great cost effective solution for those who want to lower their car but also want the freedom to adjust the ride height after the installation. With Height Adjustable Lowering Springs you will be able to combine the best of a coilover with the cost benefits of  lowering springs.

Height Adjustable Lowering Springs essentially combines the height adjustable functionality of a coilover with the OE (electronically controlled) factory shock absorbers. They are also called HAS Kits, VTF Kits or ALS kits. The springs are designed to provide a lower ride height than stock, similar to what regular lowering springs do. However, with Height Adjustable Lowering Springs you add the height adjustable functionality to the OE Shock by using Height Adjustable Sleeves or Platforms. We also call these Pre-Load Adjusters or Height Adjusters. With these installed, you will be able to alter the ride height by raising or lowering the Height Adjuster, usually by rotating the Spring Perch up or down on machined screw-thread. The proces of adjusting the ride height on Height Adjustable Lowering Springs is similar to a coilover.

• Height Adjustable Lowering Springs (HAS Kits) are sleeves with screw-thread for your OE Electronically Controlled shock absorbers so you can alter the ride height after installation of the kit.

Adaptive Suspension is a option that allows the driver of the vehicle to adjust the suspension settings on the go. The shock absorbers can be put into a stiffer (Sport) or softer (Comfort) setting with a push of the button. With the settings in Sport, the driver will feel more of the road and essentially get a crashier ride, while with the settings in Comfort, the driver will enjoy a more compliant ride for longer distances. With Electronically Controlled Damping, also called EDC or DDC, becoming a more and more popular option on premium and even mainstream vehicles, it is only a matter of time until more and more HAS kits are being developed. The HAS allows the owner of the vehicle to keep the often expensive DDC option while also have the car lowered for a better stance and look. While coilovers offer similar functionality for those who seek height adjustability, it also remove the DDC, unless you go for the more expensive options. The HAS kit offers best of both worlds. 

With Lowering Springs, you will get a similar lower ride height, but it is not possible to alter the ride height without removing the springs completely and replace them for a taller or lower kit.

• EDC / DDC are options that give the driver electronic control over the characteristics of the suspension, a usually expensive option that you do not want to give up.
• You are able to keep the EDC / DDC functionality with a Height Adjustable Lowering Springs Kit.
• You will get height adjustability with Height Adjustable Lowering Springs Kit on OE shock absorbers.

HAS kits are designed for cars with EDC / DDC. While Adaptive Suspension is getting more mainstream, it is still a relatively expensive option. You will find this option more often on the higher end performance cars, like cars from the BMW M division, Mercedes AMG, Audi RS, Volkswagen GTI / R or supercars, like Porsches, Ferraris or Lamborghinis. Most HAS kits retail between €600 to €1200,-, so while not as expensive as a premium coilover, it is also not a super cheap suspension upgrade. It does bring a lot of value to the table, so it certainly has its place in the suspension market. The products are often developed for the higher end cars as these are the cars most often equipped with Adaptive Suspension.

Popular Models

• BMW G80 M3 / G82 M4
• BMW G42 M240i
• BMW G20 M340i
• BMW F80 M3 / F82 M4
• BMW F90 M5
• Volkswagen Golf 7 GTI / R
• Volkswagen Golf 8 GTI / R
• Mercedes-Benz C63 AMG
• Mercedes-Benz A45 AMG

Height Adjustable Lowering Springs are getting more popular, but the main manufacturers of these products include the following brands:

• KW Suspension
• ST Suspension
• Cobra Suspension
• H&R
• MSS 
• AST Suspension

We love getting nerdy around the technical aspects of the products we supply, so let's explain how these products work.

Since the OE shock absorbers and spring seats do not have the height adjustable functionality from the factory, you will need to alter the way the spring sit on your OE shock absorbers. To accomodate this, you will need to install a so-called Height Adjuster, sleeve or pre-load adjuster. Specific installation differs from vehicle to vehicle, but in general, you will need to remove the OE spring seat so you can install a pre-load adjuster with machined screw-thread instead. This principle is similar for the front and rear, but again, it differs from car to car.

• Height Adjusters installs onto or replaces the OE spring and provides height adjustability instead of just a fixed spring seat.

The springs are usually designed with the same target as a lowering spring, which is of course lowering the car. The HAS kit springs come with a grounded surface on the top or bottom of the spring. This grounded surface sits flat on the Height Adjuster. The other main purpose of lowering a car is of course provide better handling. While you are limited to what you can achieve with just a HAS kit, the lower ride height does provide a more controlled rolling behaviour and usually gives a bit more feedback through the steering wheel and body. The springs on Height Adjustable Lowering Spring kits are designed to lower the car to a maximum of about 30 to 45mm (about 1.2" to 1.8") with the spring perches in the lowest setting. This varies per vehicle, but it is a good estimation of what the HAS Kits offer. From the lowest setting you will also be able to raise the ride height to about a minimum of 10-20mm lowering. This means even though you have height adjustability, your vehicle will usually not reach OE ride height.

• Springs have Grounded surface to sit flush onto the spring Height Adjusters.
• Lowering can be altered between certain values on the Height Adjustable Lowering Springs.

This brings us to the limitations of the HAS kit. The requirements set by the manufacturers and limitations of the OE shock does not allow the spring to sit on OE ride height because this could cause coil-binding. If you raise the spring too high, it is possible that the increased spring travel will cause coil-bind because the compression point where the bump-stop prevents the spring from coil-binding is has been shifted to a later point during the compression. When designing a spring for a HAS kit, the manufacturer always puts safety first, so there's always a minimum and a maximum ride height. Within these margins, the suspension can operate safely. 

It also means that the stated maximum lowering on the kit is the maximum lowering the kit has been safely rated for. A spring manufacturer will always consider the maximum axle loads and does not allow this limit to be exceeded. So for example, if a manufacturer states 40mm as the maximum lowering amount, it means that car should not exceed this value for safe operation, even if there's still 10 to 15mm thread left. This depends on the vehicle configuration and suspension design. However, this info can usually be found in the manual.

Manufacturers will also sometimes provide shorter bump stops with some HAS kits. This bump stop allows the car lower more, while also protecting the shock absorber for excessive travel. This bump stop is usually only used when you need the car to go a bit lower than the OE bump stops allow. 

• The limitations with OE shock absorbers is that you work within a certain technical aspects. It offers a lot of adjustability, however, it is always recommended to keep within the margins the manufacturer of the Height Adjustable Lowering Springs mentions.

Height Adjustable Lowering Springs offer similar ride performance as lowering springs. They offer similar comfort levels and similar balance when driving with a sportier driving style. The car will have less body roll due to the lower ride height, however, it will still retain the OE Shock absorber damping characteristics. After all, these are the parts that didn't change when installing the HAS Kit.

The suspension manufacturers do have their own characteristics, but generally, you can compare the ride quality with their lowering springs. A brand more focused on comfort will also have more comfortable Height Adjustable Lowering Springs. A brand focused more on on a sportier ride, will also have sportier riding Height Adjustable Lowering Springs. 

Comfier

• Cobra Suspension
• AST Suspension

Sportier

• KW Suspension
• ST Suspension
• H&R
• MSS 

When working with the OE Shocks, you will always run into pros and cons. What is our verdict? Let us explain.

• You get to keep the stock / OE Shock Absorbers EDC / DDC fucntionality while also getting Height Adjustability with the HAS Kit. 
• You will be able to raise or lower the ride height after the installation without re-doing the whole installation proces.
• The Height Adjustable Lowering Springs ride relatively the same as a OE shock with lowering springs on Adaptive Suspension.
• In most cases, the Height Adjustable Lowering Spring Kit is a reversible modification, so you can always return to stock.
• Height Adjustable Lowering Springs are a relatively cheap modification compared to a mechanically adjusted or DDC premium coilover.

• Manufacturers of the Height Adjustable Lowering Springs have to work with the limitations of the OE shock absorber, so they are not always able to provide the best of the best spring vs. shock absorber balance.
• A premium high end coilover still provides more mechanical performance when you track a car and will outperform the Height Performance Lowering Springs on pure pace.

The Height Adjustable Lowering Springs are a perfect solution for those who are looking for a lowering option with height adjustability without losing the OE EDC / DDC Shock absorbers for a coilover. We recommend the HAS kit to people who daily their car and are looking for a relatively affordable option to give their car a better look and an improvement in handling. There's a certain group that will opt for the fixed lowering springs and a certain group that go for the coilovers. If you are looking for the most cost effective option, you'd probably go for a lowering spring. If you track your car, we will always advice to go for a track coilover. However, we believe that the Height Adjustable Lowering Springs are a great solution for those who fall in between. How often did you run into the issue that after installing a front splitter after you lowered your car that the car is too low? Or that you're not 100% happy with the ride height on lowering springs? With a few turns on the Height Adjuster to set it a little higher and your problem is solved.

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Special thanks to Cobra Suspension for providing us the technical background. See our suspension catalog.