REFERENCE 32-00 · RUNNING GEAR
Fastener Torque Spec Chart
Lug nuts, suspension U-bolts, and hanger/shackle bolts — the fasteners most responsible for a wheel or axle failure on the road. Covers travel trailers and fifth wheels through Class A motorhomes.
The wheel/axle manufacturer’s spec always governs. Torque values below vary by wheel maker (Lionshead, Dexter, Lippert, and others) and stud size — use these as a sanity-check range, not a final answer. Always check the spec plate or the manufacturer’s current manual before torquing.
Lug Nut Torque (Conical Seat)
| Stud Size | Torque Range | Common On |
|---|---|---|
| 1/2″ | 90–120 ft-lb | Smaller travel trailers |
| 9/16″ | 120–140 ft-lb | Mid-size trailers, some 5th wheels |
| 5/8″ | 150–175+ ft-lb | Larger 5th wheels, single-axle heavy haulers |
| 17.5″ dual/flange configs | 190–325 ft-lb | Class A motorhomes, large toy haulers |
Re-torque rule: re-check lug torque after the first 10–25 miles on any newly mounted wheel, then again at 50–100 miles — fasteners seat and settle under initial load. Torque in a star/cross pattern, never sequentially around the circle.
Suspension U-Bolt Torque
| Axle Rating | Bolt Size | Torque |
|---|---|---|
| 2,000 lb | 3/8″ | 35 ft-lb |
| 3,500–8,000 lb | 1/2″ & 9/16″ | 65 ft-lb |
Check U-bolt torque with the coach’s weight on the tires (not jacked up), every 6 months or 6,000 miles — whichever comes first.
Hanger & Shackle Bolts
Equalizer hanger and shackle bolts on leaf-spring trailer suspensions typically torque to ~35 ft-lb. These should move freely (they’re a pivot point, not a rigid joint) — over-torquing can bind the equalizer and cause premature wear. Inspect for elongated holes or cracked hangers at every axle service.
Related Reference Pages
Tires, TPMS & Brakes Guide
Chassis & Engine Maintenance Guide
Seasonal Maintenance Checklist
Full Field Guide
⚠ Safety note: This page is for informational purposes only and is not a substitute for the advice of a qualified professional. Under- or over-torqued wheel and suspension fasteners can cause wheel separation or axle failure while towing or driving. Always verify torque values against your specific wheel/axle manufacturer’s current spec plate or manual, and use a calibrated torque wrench. United Mobile RV LLC is not responsible for outcomes of DIY work performed using this reference. Rev. 1 — August 2026.
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