STEP 1
Checking coilover clearance and springs
CLEARANCE
Ensure there is enough clearance around the coilovers, the air cups are 110 or 120mm in diameter, the fitting is 17mm.
SPRINGS
The air cups can only be installed on linear springs. They will not fit shaped springs, as shown in the figure. In most cases, shaped springs can be replaced with linear springs.
STEP 2
Measuring shaft and spring diameters
DAMPER SHAFT
Measure the thickest part of the shaft using a caliper, measure below any rings or clips.
Air cups are available for coilover shaft diameters: 12.5mm, 14mm, 15mm, 16mm, 18mm, 20mm, 22mm, 25mm, 40mm, 42mm, 44mm, 44.2mm, 44.5mm and 45mm.
SPRING DIAMETER
Maximum outer diameter: 98mm (89mm for the smaller 110mm air cups).
Minimum inner diameter: 60mm (57mm on request).
There might be a code on the spring indicating the inner diameter, such as 60, 61, 62, or 65 for ID60, ID61, ID62, and ID65mm springs, which are all fine! For example, "62-200-008" means it has an inner diameter of 62mm.
STEP 3
Installation
RIDE HEIGHT
The air cup adds between 20 and 30mm in height. The air cup itself is 20mm thick, and with most coilovers, the top hat sits on top of the air cup, adding approximately 10mm. If there is enough thread left on the coilovers to lower the springs by 30mm, there won’t be any issues. If not, shorter springs will be required.
SPRING ADJUSTMENT
The lift from the air cups requires droop from the coilovers. If there is not enough droop, the air cups will not be able to lift the full 50mm. The damper strut simply will top out before achieving the full lift. If you're using the standard spring rates that came with your coilovers, it should be fine. If you're using higher spring rates we recommend to use helper springs to get the full lift.
WHAT IS DROOP?
Droop is the suspension travel between normal ride height and full extension. The available droop determines how far the air cups can lift the car.
To check the available droop, jack up the car until the wheels are off the ground. Measure the increase in distance between the wheel and the fender. This is the maximum lift available, up to 50mm.
SEPARATED REAR SPRING AND SHOCK
Custom rear cups
FITMENT REQUIREMENT
Custom rear cups are available for a limited selection of cars with a separate rear spring and shock. Linear springs required, minimum length with air cups installed: 150mm.
We have 2 versions of custom rear cups available:
50mm custom rear cup
- Height adjuster thread diameter: max 50mm
- Minimum spring inner diameter: 62mm
- Maximum spring outer diameter: 105mm
53mm custom rear cup
- Height adjuster thread diameter: max 53mm
- Minimum spring inner diameter: 65mm (!)
- Maximum spring outer diameter: 105mm
INSTALLATION:
The custom rear cup will add 30 mm to the stack height. If there is enough thread left on the spring perch to lower the springs, this will not be a problem. If not, shorter springs will be required.
Custom rear cup specifications:
- Diameter: 130mm
- Height: 83mm
- Air cup stroke: 25mm (resulting in an actual lift of 40-50mm due to the suspension geometry).
An air cup lift system is also known as air cup suspension, an air cup kit or a coilover lift system.