Monotube gas-pressurized shocks in lift-appropriate lengths. The default upgrade for stock-to-4.5" XJs; durable, well-valved, modest cost.
The Bilstein 5100 is the go-to XJ shock upgrade. Monotube design with a 46mm bore and digressive valving — firm initial damping, then opens up over bumps. Bilstein makes 5100s sized for stock, 2", and 4" lifts. For stock to 2" lift, use 24-185783 (front) and 24-185769 (rear). For 3-4" lift, use 24-186162 (front) and 24-186179 (rear).
5100s are good for ~80% of XJ builds: daily drivers, overland rigs, mild-to-moderate trail trucks. They run cool, they don't fade over rough roads, and the seals last 80,000+ miles. They will not match the trail performance of Fox or King 2.0 IFP shocks (the 5100 valve is fixed, no remote reservoir), but they cost half as much and run forever.
The shock body diameter is 46mm — make sure your skid plates and tire clearance allow this. Bilstein 5100s use stem mounts top and bottom on the XJ; no adapters needed for stock and most lifts. Yellow paint is iconic.
For a 4.5" lift, the 5100 is at the upper end of its travel — fine for daily driving but if you do hard wheeling that drops a wheel into a hole, the shock can bottom or top out. Above 4.5" lift, step up to Fox 2.0 or King 2.0 IFP.
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| Part | Vendor | Est. price |
|---|---|---|
| Bilstein 5100 front (stock/2" lift) | Bilstein | ~$75 |
| Bilstein 5100 rear (stock/2" lift) | Bilstein | ~$70 |
| Bilstein 5100 front (3-4" lift) | Bilstein | ~$80 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.