2024 Jeep Rubicon JLUR X 37s Upgrade: Re-Gear, Lift, Spacers?

Summary

You can run 37s on a 2024 JLUR X with 4.56s, but to keep full articulation and not chew sheet metal, you’re realistically in 2.5" lift territory with proper bump stops and wheel offset. Gears are “livable” with 4.56, but not ideal.

Best upgrade path

1. 37s on proper wheels (no regear yet) — Use your 4.56s, correct wheel offset, and a 2.5" lift/bump stop setup; see how you like the highway manners before spending gear money.
2. Regear later if needed — If you hate the highway feel or tow in the hills, step to 4.88 or 5.13.
3. Keep stock wheels? — Then you’re into quality hub‑centric spacers and more careful bump stop tuning.

The parts to do it right

• 37x12.50R17 tires — Common size, works well on 8.5" wheels.
• 17x8.5 wheels, 0 to -12 mm offset — Clears control arms and sway bar without silly spacers; keeps scrub radius reasonable.
• 2.5" JL Rubicon‑specific lift with bump stop extensions — The factory X “lift” isn’t enough for full‑flex 37s; you’ll stuff them into fenders.
• Adjustable front lower control arms — Get caster back after lift so it tracks straight at 75+ mph.
• Rear tire carrier reinforcement / hinge system — A 37" spare will beat the stock tailgate to death.
• Front driveshaft upgrade (double‑cardan) — Stock shaft boots don’t like big droop with 2.5"+ lift and 37s.
• Steering correction (track bar + maybe stabilizer) — Keeps it tight and reduces wander with heavier rubber.
• Programmer / TPMS & tire size calibration — Fix speedo, shift points, and TPMS thresholds.

Things to consider

• 4.56 + 37s: usable, but you’ll feel it on I‑70 climbs; 8‑speed helps a lot.
• For real flexy Colorado trails, 2.5" lift + good bump stops is the sweet spot; 1.5" factory X height is marginal.
• If you insist on stock wheels, plan on ~1.75" hub‑centric spacers and more fender rub risk.
• Inner fender liners and pinch seams may still need a little love depending on exact tire and wheel.
• Bigger brakes aren’t mandatory, but keep pads/rotors fresh; 37s add stopping distance.

Realist expectations & tradeoffs

• You’ll lose some snap off the line and in 8th; expect more downshifts on grades.
• Steering will feel heavier and more vague than on 33/35s, even with everything set up right.
• MPG will drop; 2–4 mpg hit is normal.
• More unsprung weight = more wear on ball joints, unit bearings, and steering components.
• Regear (4.88/5.13) is a “nice to have” for highway comfort, not a hard requirement with your 4.56s.

Questions

1. Are you keeping the factory Rubicon X wheels or open to new wheels?
2. How hard are your “moderate” trails (full flex on obstacles, or mostly forest roads)?