Stock 3.55 is right for 30" tires. 33s want 4.10-4.56. 35s demand 4.56 with AW4, 4.88 manual. Stroker shifts the math right by one ratio step.
Gear ratio selection is about RPM at cruise (60-70 mph in OD), torque at trail crawl (lockup speed at low engine RPM), and the engine's powerband. The standard XJ guidance:
37" tires: 4.88-5.13. At this point you also need axle upgrades.
Stock 4.0L, manual (AX-15/NV3550):
Add one ratio step compared to AW4 because manual lacks the AW4's lockup converter help.
33" tires: 4.56
35" tires: 4.88-5.13
37" tires: 5.13-5.38
Stroker 4.6/4.7:
Shift left by one step — stroker has 25-30% more torque, can pull taller gears.
33" tires: 3.73-4.10
35" tires: 4.10-4.56
37" tires: 4.56-4.88
RPM at 70 mph in 4th (AW4 OD) for reference:
31" + 3.55: 2000 RPM
33" + 4.10: 2200 RPM
33" + 4.56: 2500 RPM
35" + 4.56: 2350 RPM
35" + 4.88: 2500 RPM
The '4.56 with 33s' rule is the canonical XJ answer for stock-engine wheelers. With a stroker, 4.10 with 33s is fine.
The rear axle determines available ratios. Dana 35 and 8.25 stop at 4.88 from major vendors. Dana 44 and Ford 8.8 go to 5.13 or 5.38 from Yukon/Motive.
Why it works
quick reference
Trade-offs
one-size doesn't fit all builds
Sources
{'title': 'XJ Cherokee Gear Ratio And Tire Guide', 'url': 'https://www.offroadxtreme.com/news/quick-help-xj-cherokee-gear-ratio-and-tire-guide/'}
{'title': 'Quadratec gear ratio guide', 'url': 'https://www.quadratec.com/c/reference/best-gear-ratio-when-adding-larger-tires'}
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.