The Lainer Suspension cartridge AIR side seal is a service part for WP AER fork systems, used to maintain sealing within the air-side cartridge. It is specified as 12x18x3.75/5 and is listed for WP AER 35, AER 43 and AER 48 applications. Replace this seal when servicing the cartridge or if air-side sealing issues are suspected; it should not be changed if the cartridge is not being opened and sealing performance is stable.

Inside the System

In WP AER forks, the air-side cartridge relies on internal sealing to retain pressure and separate chambers correctly. This seal is intended for the cartridge air side and forms part of the sealing stack that supports consistent operation of the air system.

Serviceability

  • Change during cartridge rebuilds and scheduled servicing where the cartridge is disassembled.
  • Replace if there are signs consistent with seal wear or damage during inspection (for example, visible deterioration when the cartridge is opened).
  • Do not replace solely as a precaution if the cartridge is not being opened and there are no issues to address.

Compatibility

  • WP AER 35
  • WP AER 43
  • WP AER 48

Applications listed: KTM SX-F 250/350/450 (2016–2021); KTM SX 125/150/250 (2016–2021); Husqvarna FC 250/350/450 (2016–2021); Husqvarna TC 125/250 (2016–2021); KTM SX 85 (2018–2021); Husqvarna TC 85 (2018–2021); KTM SX 65 (2018–2021); Husqvarna TC 65 (2018–2021); GAS GAS (2021).

Key Features

  • Cartridge air-side seal for WP AER fork systems
  • Size listed as 12x18x3.75/5
  • Intended for servicing and rebuild applications

Setup & Workshop Notes

  • Confirm the required seal specification against the exact WP AER fork and cartridge version before installation.
  • Inspect associated cartridge sealing surfaces during service; replacing a seal alone may not resolve issues if mating surfaces are damaged.
SKU SEAL_CART-AIR_12X18WP
Brand Lainer Suspension
Shipping Weight 0.1000kg
Shipping Size 0.050 x 0.050 x 0.050m
See our Shipping Information See our Frequently Asked Questions

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