2 Pcs Air Spring Bag for Trucks Fits Hendrickson S-20900 S-21800

In this review of the 2 Pcs Air Spring Bag for Trucks, the bottom line is straightforward: this kit is for fleet mechanics and truck owners who need a rugged, OE-quality replacement for Hendrickson trailer and AAT 23K suspensions. The reviewer found the construction-4.5-5.0mm high density rubber and 4140 grade steel studs-gives a noticeably firmer, leak-resistant ride compared with worn original bags. Installation is direct when the part numbers match, and the included dimensions make fit verification simple before purchase.

Key Features

• Heavy-duty rubber: 4.5-5.0mm thick high density rubber exceeds typical OEM thickness and improves durability under heavy loads.
• Reinforced studs: 4140 grade steel studs are 25% stronger than standard studs, reducing stud failure risk during heavy service.
• Leak-tested: Each spring bag is tested for maximum leakage, which helps maintain consistent air pressure and ride height.
• Wide compatibility: Fits a long list of Hendrickson and AAT part numbers so many S-20900/S-21800 and AAT 23K users can replace units without modification.
• Clear dimensions: Top plate width, piston width, and compressed/extended heights are listed to ensure a correct fit when cross-checking parts.
• Warranty support: Backed by a 3 year unlimited-mileage quality guarantee for added confidence in long-term use.

Who It's For

This kit is aimed at commercial truck owners, trailer maintenance shops, and fleet supervisors who service Hendrickson Intraax and Van Traax or AAT 23K suspensions and need a robust replacement part that closely matches OEM performance. The reinforced studs and thicker rubber make it especially useful where higher load cycles or heavier duty service are common.

It is not for users who have not verified their exact part number; buyers should check compatibility with W01-358-8709, 1R13-159 and the listed Hendrickson codes before ordering. Owners of non-compatible suspension models should look for a bag explicitly listed for their part number rather than assuming interchangeability.

Pros & Cons

Pros

• Durable construction from thicker rubber improves service life under heavy loads.
• Stronger 4140 steel studs reduce the chance of stud deformation or failure in demanding applications.
• Each bag is leak-tested, helping to ensure reliable air retention and ride consistency.
• Comes with a clear 3 year unlimited-mileage quality guarantee for peace of mind.

Cons

• Compatibility requires careful part number verification, so it may not be a drop-in for all trailers without confirming specs.
• The weight and size mean professional handling or shop installation is recommended for most users.

Specifications

Material	4.5-5.00mm high density rubber
Reinforcement	4140 grade steel studs (25% stronger)
Top Plate Width	10.38 in
Piston Width	9.15 in
Compressed Height	6 in
Extended Height	19.4 in
Weight	14 lbs
Warranty	3 year unlimited-mileage quality guarantee

Our Verdict

The 2 Pcs Air Spring Bag is a sensible replacement for Hendrickson and AAT 23K applications when the part numbers match; it offers thicker rubber, stronger studs, and leak-tested construction that deliver durability and reliable ride performance for heavy-duty service. For fleets and repair shops seeking value and a backed warranty, it represents a practical, long-lasting choice.

Frequently Asked Questions

Will these bags fit my Hendrickson axle?
They fit S-20900, S-21800, C-20900 and C-21800 families and listed cross-reference numbers, but always verify your exact part number before purchase.

What is the warranty period?
The product includes a 3 year unlimited-mileage quality guarantee; contact the seller for warranty support.

Are the studs stronger than OEM?
Yes, the studs are 4140 grade steel and are specified as 25% stronger than standard studs to improve durability.