Your cart is empty
Browse our catalog to find the parts you need.
These images are illustrative and may not match the product exactly. Always verify by part number — or confirm instantly with the assistant using a photo or VIN.
Firestone · Suspension & Steering
9921
In stock · ships from Knoxville
This is a rolling lobe air spring (air bag) used in heavy-duty truck and trailer suspension systems.
Confirm the part fits before you buy. Applications and interchange numbers are researched and audited per part.
Verified fitment for 3 applications
Add your truck to see whether it's one of them
All confirmed applications for this part number.
Other applications
Other applications
Verify your existing air bag part number or dimensions (compressed/extended height, top/bottom plate sizes) before ordering. This 9921 cross-reference covers a wide range of aftermarket and OEM numbers.
Part data verified against 4 catalog sources
Numbers this part supersedes or interchanges with. Showing 13 of 13.
Different year, make, or config? Get a confirmation against your truck in under a minute.
It mounts between the axle and frame to support vehicle weight and absorb road shocks, delivering a smoother ride. When the air bag develops leaks, cracks, or fails to hold pressure, ride height and load carrying ability are compromised—replacement restores proper suspension performance. The 9921 model is a common replacement for many Hendrickson, Neway, and Watson & Chalin trailer air-ride suspensions.
Part Number: 9921
AIR BAG
Unit: ea
Dealer: Knox Trailers
Compatibility, alternatives, and more
Parts commonly needed alongside suspension & steering
