2024 Jeep Rubicon X 37s Tire Upgrade: Re-gearing, Spacers & Lift?

You’re on the right track, but 37s on a JLUR X (Rubicon X) with 4.56 gears and the stock “X” 1.5” lift will push the limits of what’s truly bolt-on. Here’s the real-world breakdown: 4.56s will work, but you’ll feel the loss of power and shift quality, especially on Colorado highways. You’ll also run into clearance and articulation issues if you don’t address bump stops, backspacing, and possibly lift height.

Top recommendations (ranked)

1. Yukon 4.88 Ring & Pinion Gears — Restores power, shift points, and driveability on 37s; $900–$1,500 parts + $1,000–$1,500 labor; pro install only.
2. Spidertrax 1.5" Wheel Spacers — Clears 37s on stock wheels, prevents rubbing; $200–$250; DIY-friendly but torque and retorque critical.
3. Falcon 2.1 Monotube Shocks — Best ride/handling for 1.5–2.5" lift, controls 37s well; $600–$800; DIY/moderate.
4. Synergy Adjustable Front Control Arms — Fixes caster, centers axle after lift/37s, improves handling/articulation; $500–$700; moderate/pro.
5. Synergy Tire Carrier Reinforcement — Prevents tailgate damage from 37s; $300–$400; DIY-friendly.

Compatibility & prerequisites

• Confirm axle ratio (you have 4.56, but 4.88 is ideal for 37s with the 8-speed auto).
• Check wheel specs: Stock Rubicon wheels need spacers for 37x12.50s (backspacing issue).
• Verify lift height: 1.5" is the bare minimum — you’ll need at least 2–2.5" for full articulation off-road.
• Bump stop extensions are a must to prevent fender/tire contact.
• Driveshaft clearance: Front shaft may contact exhaust at full droop with more lift.
• Speedo/tire size calibration: Required for proper shifting and ABS.
• Emissions: Gear swaps and tire size changes are legal, but always check local rules.

Realistic expectations & tradeoffs

• 4.56s + 37s: Usable, but sluggish in 8th gear and on grades. 4.88s or 5.13s drive much better.
• Wheel spacers: Safe if quality, but need regular retorque (every oil change).
• Ride quality: Slightly firmer, more body roll with 37s and higher lift.
• MPG: Expect a 2–4 mpg drop.
• Maintenance: Bigger tires = more wear on ball joints, steering, brakes.
• Warranty: Gears, spacers, and lifts can affect coverage on related parts.

A few questions

• Are you planning to keep the stock wheels, or will you upgrade to aftermarket wheels with less backspacing?
• How much off-road articulation do you actually use? (Mall-crawler, mild trails, or full flex?)
• What’s your budget for gearing and supporting mods?

Let me know your answers and I’ll dial in the best path for your setup. If you want to run 37s right, plan for at least 2.5" lift, bump stops, and ideally 4.88 gears. Don’t skip the wheel spacers or you’ll chew up your fenders and pinch seams.