The JL Rubicon is the only Wrangler that fits 37s from the factory without modification — and even on the Rubicon you will get occasional flex rubbing. On every other JL trim, 37s require a lift and a plan.
Jeep was deliberate about the JL Rubicon's tire clearance. The Rubicon comes with a 1" front lift, wider fender flares, and 33" tires from the factory — but the geometry allows for 37s with minimal clearance work at full flex. In practice, 37s on a stock Rubicon rub at full steering lock combined with full bump travel. The rub points are the front upper control arm at the coil bucket and the rear fender liner at full droop. Most Rubicon owners address this with a 1"–1.5" spacer lift or minor fender liner trimming without a full kit.
Non-Rubicon JL trim levels (Sport, Sport S, Sahara) are a different situation. The factory fender openings are narrower, the suspension geometry is lower, and the tires are 31"–33" from the factory. Fitting 37s without a lift results in rubbing at every steering and suspension extreme — you need 2.5" of lift minimum, and 3.5" is the more comfortable clearance baseline. At 2.5" you will still need fender liner removal (not cutting, pulling the liner) at the rear, and the front upper control arm area needs attention at full steering lock. At 3.5", 37s fit cleanly across all four corners.
The tire choices matter for fitment as much as the size. A 37x12.5R17 is the most common spec, and all three recommended options here are in that range. Note that actual measured width varies by brand — the BFG KM3 at 37x12.5 measures close to nominal, the Nitto Trail Grappler runs slightly narrower, and the Toyo Open Country MT runs slightly wider depending on the wheel backspacing. On a 17x8.5 or 17x9 wheel with 4.5"–5" backspace, all three mount cleanly.
**Regear is not optional at 37s.** Stock gear ratios on the Sahara (3.45) and Sport (3.73) were engineered around 31"–33" tires. Adding 37s effectively drops your RPM at highway speed and loads the drivetrain heavily off-road. The Sahara with 3.45 gears and 37s is genuinely painful to drive — low-end torque evaporates, the transmission hunts gears on grades, and trail crawl ratios are inadequate. Plan for 4.56 gears with 35s, 4.88 gears with 37s on Sahara/Sport. Rubicon owners with the 4.10 stock ratio can run 37s tolerable, but 4.56 is the right answer for serious trail use.
**TPMS:** The JL uses a direct TPMS system — sensors in each wheel. When you move to aftermarket wheels, the sensors must either be transferred from factory wheels or new sensors purchased and programmed. TPMS sensors for the JL are vehicle-specific; verify compatibility before ordering.
| Part | Vendor | Est. price |
|---|---|---|
| BFGoodrich Mud-Terrain T/A KM3 37x12.5R17 | BFGoodrich | ~$320 |
| Nitto Trail Grappler M/T 37x12.5R17 | Nitto | ~$295 |
| Toyo Open Country M/T 37x12.5R17 | Toyo | ~$285 |
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.