← Back to TekJeep AI · All fitment answers
Will 40-inch tires fit a Jeep JL with a 4-inch lift?
Fitment answer · Updated October 27, 2026
Short answer
Yes, but it is a full build. 40s on a 4-inch JL need high-clearance fenders, bump stops, low-backspacing wheels, steering upgrades and a deep regear. Many owners also upgrade the axles.
Shop the gear for this build ↓ Tires, deflators and a compressor picked for this setup.
What you usually need
- High-clearance or trimmed fenders and bump stops tuned for full stuff.
- Wheels with the right backspacing for 40s and a heavy-duty spare carrier.
- Heavy-duty tie rod, drag link and steering stabilizer, plus brake upgrades.
- Stronger axles are common, especially on non-Rubicon trims.
Regearing
40s on a JL usually call for 5.13 or 5.38 gears. 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.
Amazon Associates disclosure: As an Amazon Associate, TekJeep AI earns from qualifying purchases. These links include our affiliate tag tekjeep-20.
FAQ
Do 40s fit a 4-inch JL?
Yes, with high-clearance fenders and bump stops.
Do I need axle upgrades?
Often, especially on Sport and Sahara trims.
Do I need to regear?
Yes, usually 5.13 or deeper.
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 JL Sport · 33s on a stock JL · 37s on a JL Rubicon · 35s on a stock JL Rubicon · 35s on a JL with a 2.5" lift · 33s on a leveled or 2.5" lifted JL · 35s on a JL with a 3.5" lift · 37s on a JL with a 3.5" lift
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