Step 1: Check Clearance
Clearance
Make sure you have enough clearance around the coilovers. The air cups are 120mm in diameter, and the fitting is 17mm (110mm air cups are available on request).
Spring Shape
The air cups can only be installed on linear springs and will not fit on 'shaped' springs, as shown in the figure. In most situations, it is possible to replace shaped springs with linear springs.
Step 2: Measure Diameters
Damper Shaft
Measure the thickest part of the shaft with 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, 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
In most cases the air cup will take between 20 and 30mm of height. The stack height of the air cup itself is 20mm but with most coilovers the top hat comes on top of the air cup, this will take around 10mm. If there is enough thread left on the coilovers to lower the springs, it won't be a problem. If not, you will need to install shorter springs.
Spring Adjustment
The lift from the air cups requires droop / rebound from the coilovers. If you don't have enough droop, the air cups can't 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.
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 take 30mm of height, If there is enough thread left spring perch to lower the springs, it won't be a problem. If not, you will need to install shorter springs.
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).