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Will 40-inch tires fit a Gladiator with a 5-inch lift?
Fitment answer · Updated October 27, 2026
Short answer
Yes, with supporting work. A 5-inch Gladiator clears 40s better than lower lifts, but you still want high-clearance fenders, bump stops set for full stuff and low-backspacing wheels. The heavy truck makes axles, steering and brakes the real limit.
Shop the gear for this build ↓ Tires, deflators and a compressor picked for this setup.
What you usually need
- High-clearance fenders and bump stops tuned for full stuff.
- Wheels with about 4.5-inch backspacing.
- Axle reinforcement, heavy-duty steering and big brakes.
- A plan for the spare, which will not fit the factory spot.
Regearing
40s on a Gladiator need deep gears, typically 5.38 or lower. Compare ratios in the Tire & Gear Calculator before you buy gears.
Compare
Gear for this build
- Mud-terrain tires (search) — Louder on the highway; buy for real mud use.
- Staun tire deflators — Repeatable trail pressures.
- VIAIR 88P portable compressor — Air back up before the highway.
- YUNPEAK 1.26" × 30' kinetic recovery rope — Bigger tires, bigger trails: carry recovery gear.
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FAQ
Do 40s fit a 5-inch Gladiator?
Yes, with supporting work.
What else do I need?
High-clearance fenders and bump stops tuned for full stuff.
Do I need to regear?
40s on a Gladiator need deep gears, typically 5.38 or lower.
Check your numbers
Use the free Tire & Gear Calculator to see speedometer error, highway RPM and a regear target, or ask TekJeep AI on the homepage with your year, trim, lift and wheel specs.
Related guides: All-terrain & mud-terrain tires · JK 2.5" lift overview
More fitment answers: 35s on a Gladiator JT · 33s on a stock Gladiator JT · 37s on a Gladiator JT · 35s on a 2.5" Gladiator · 37s on a 3.5" Gladiator · 35s on a stock Mojave · 35s on a stock Gladiator Rubicon · 33s on a leveled Gladiator
Fitment disclaimer: Clearance depends on exact tire size, wheel specs, suspension and how hard you flex. Confirm with your tire shop or installer before buying.
Tire size how-tos: How to read a tire size · Bolt pattern & backspacing · Regearing for bigger tires · Tire pressure after upsizing · Speedometer error · Rubbing fixes