Air cup lift systems fit any brand of coilovers as long as your setup meets the requirements below. Work through these three steps with a caliper or tape measure before you order, and you'll get the right cups the first time. Questions at any point? Email info@pmddriven.com and we'll walk you through it.
Weight limit: max total vehicle weight is 2,000 kg / 4,400 lbs. For 40–45 mm cups the limit is 1,750 kg / 3,850 lbs.
Check Clearance & Spring Type
Clearance
Make sure there's room around the top of each coilover. The air cups are 120 mm in diameter and the air fitting adds 17 mm. Tight on space? Smaller 110 mm cups are available on request — just ask us.
Springs
Air cups only install on linear (straight) springs. They will not fit barrel, tapered, or otherwise "shaped" springs. If your coilovers run shaped springs, they can usually be swapped for linear springs — we can help you spec a set.
Measure Shaft & Spring Diameters
Damper Shaft
Using a caliper, measure the thickest part of the shaft, below any rings or clips. Cups are made for these shaft diameters:
- 12.5, 14, 15, 16, 18, 20, 22 and 25 mm
- 40, 44, 44.2, 44.5 and 45 mm
Spring Diameter
Maximum outer diameter: 98 mm (89 mm for the smaller 110 mm cups). Minimum inner diameter: 60 mm (57 mm on request).
Tip: many springs are stamped with a code — "62-200-008" means a 62 mm inner diameter. ID60, ID61, ID62 and ID65 springs all work.
Confirm Ride Height & Droop
Ride Height
Installing air cups typically raises the spring stack 20–30 mm: the cup itself is 20 mm tall, and on most coilovers the top hat sits on top of the cup, adding about 10 mm. If there's enough thread left on the coilover body to lower the spring perch and compensate, you're set. If not, plan on shorter springs.
Droop / Rebound
The lift comes from droop — the travel between ride height and full extension. Without enough droop, the strut tops out before reaching the full 50 mm of lift. Standard spring rates that came with your coilovers are usually fine; run minimal preload. Running stiff, higher-than-stock rates? Add helper springs to restore droop and get the full lift.
Separate Rear Spring & Shock?
Custom Rear Cups
Requirements
For a limited selection of cars with a divorced rear spring and shock. Linear springs required, minimum spring length with cups installed: 150 mm. Two versions:
- 50 mm cup: height-adjuster thread max 50 mm · spring ID min 62 mm · spring OD max 105 mm
- 53 mm cup: height-adjuster thread max 53 mm · spring ID min 65 mm · spring OD max 105 mm
Installation
The custom rear cup adds 30 mm of height. If there's thread left on the spring perch to lower the springs, no problem — otherwise fit shorter springs.
- Cup diameter: 130 mm · height: 83 mm
- Stroke: 25 mm (roughly 40–50 mm of actual lift at the wheel thanks to suspension geometry)
Ready to Order? Have These Numbers
- Damper shaft diameter (thickest point, below rings/clips)
- Spring inner and outer diameter
- Confirmed 120 mm of clearance (plus 17 mm for the fitting)
- Linear springs — and enough droop / thread adjustment
Not 100% sure about a measurement? Send us your numbers and coilover model before ordering — buy once, cry once.
Email Us Your Measurements