What This Air Spring Is
This is a two-ply double convoluted bag — two lobes, no rolling sleeve. It carries the trailer axle or lift axle and rides on a composite piston. Physical numbers: 9.9 in maximum diameter, roughly 9.1 in maximum height, about 3.1 in collapsed height, and an 8.5 in design height. Design height is the number that matters when you set ride height after install.
The top is a Type 3 bead plate with two 3/8-16 blind nuts on 3.50 in centers and a 1/4 in NPT offset air port. That stud pattern and port location are what decide whether the bag drops into your bracket. Measure the centers on the old plate before you order — 3.50 in is common, but it is not the only pattern in service.
The PartStop unit is an aftermarket direct replacement built by Zhuhai Fengli and carries a 6+ month warranty. It is not an OEM part and we are not affiliated with any of the brands listed here. Their numbers appear for identification only, so you can match what is stamped on your old bag.
Why These Numbers Cross
All of these numbers describe the same physical bellows: Firestone style 20, also called 274C. Firestone sells it as W01-358-6910. Goodyear catalogs the same bellows as 2B9-200 and ContiTech as FD 200-19 320. Same convolution count, same maximum diameter, same design height envelope. The bellows is the common element — the suspension builders buy it and assign their own part numbers.
That is where the rest of the list comes from. Hendrickson stocks it as S-8768 for trailer applications and 45843-3 on other builds. SAF-Holland (Neway) uses 57006910. Ridewell calls it 1003586910C. Watson & Chalin uses AS-0001, and Triangle lists AS-4320. Different boxes, different labels, one bag with a Type 3 plate and a composite piston.
A cross-reference is a starting point, not a fitment promise. Suspension builders revise bracketry and piston mounts without changing the model name. Confirm by the number printed on the bag you are pulling, or by VIN and suspension tag, before you commit.
How These Bags Fail
Most failures are chafe and heat, not age alone. A bag that rubs a frame rail, brake hose or misaligned bracket wears through the outer ply and blisters at the convolution. Look for a shiny wear scar on the lobe. If you find one, fix the clearance issue or the replacement fails the same way in a few months.
The other common killer is running the bag past its travel — a dead shock lets the bellows slam the piston at full droop, and a leaking height control valve lets it over-extend. Check shocks and valve linkage while the wheels are up. Replace bags in pairs across an axle so ride height stays even.
W01-358-6910 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to W01-358-6910. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| ContiTech | FD 200-19 320 |
| Goodyear | 2B9-200 |
| Hendrickson | S-8768, 45843-3 |
| Ridewell | 1003586910C |
| SAF-Holland | 57006910 |
| Triangle | AS-4320 |
| Watson&Chalin | AS-0001 |
Frequently asked questions
Is this the same bag as Hendrickson S-8768?
It is built to replace the same Firestone style 20 (274C) bellows that S-8768 covers, along with 45843-3. The Hendrickson numbers are listed for identification only. Verify the number on your old bag or the suspension tag before ordering, since brackets and piston mounts do change between builds.
What is the design height on W01-358-6910?
Design height is 8.5 in, with about 9.1 in maximum extended height and roughly 3.1 in collapsed. Set your height control valve to the suspension builder's spec, not to the bag spec alone. Running below design height cooks the bellows against the piston.
How do I confirm the bead plate fits my bracket?
This bag uses a Type 3 bead plate with two 3/8-16 blind nuts on 3.50 in centers and a 1/4 in NPT offset air port. Measure stud centers on the old plate and check where the air line enters. If either differs, the number crosses but the plate will not bolt up.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
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Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.