REGEAR AND WHAT WE THINK...

What Gear Ratio Does Lunes Off-Road Recommend For 37s?

One of the most common questions we get is whether 4.56s or 4.88s are the better choice for 37-inch tires. In our experience, 4.88s are the most common ratio we install for customers moving to 37s. Can you run 4.56s? Absolutely. But we've seen plenty of customers wish they had gone deeper after spending the money on the regear.

A regear isn't an inexpensive service. You're paying for specialized setup work, bearings, seals, fluids, and labor. Because of that, we generally encourage customers to think about where they want the vehicle to be in the future rather than where it sits today.

As a general rule, we like to see customers move at least two gear ratio steps whenever possible. For example: a Rubicon equipped with factory 4.10 gears may see some improvement with 4.56s, but many owners feel the difference isn't dramatic enough to justify the cost. In many situations, 4.88s provide a much more noticeable improvement in drivability and performance.

That doesn't mean 4.88s are automatically correct for every Jeep. Vehicle weight, transmission choice, tire size, intended use, and future modifications all matter. The goal isn't to install the deepest gear available. The goal is to choose a ratio that works well for the complete vehicle package.

Why Do Some Gear Sets Fail?

Spend five minutes reading social media and you'll find thousands of opinions about gear ratios, gear brands, and axle failures. What you don't often hear is the actual reason the failure occurred. In our experience, gear failures usually fall into one of three categories.

1. Improper Setup

Ring and pinion gears require extremely precise installation.

Pinion depth, bearing preload, backlash, and gear pattern all matter.

A gear set installed outside specification may survive for a short period of time, but often develops noise, excessive wear, or complete failure later. This is one reason gear setup is considered a specialty within the drivetrain industry.

2. Break-In Procedure Was Ignored

New gears generate heat during the initial wear-in period. Proper break-in procedures allow the gear set to gradually establish a wear pattern without excessive temperatures.

We've seen failures occur because owners immediately subjected new gears to towing, extended highway driving, or aggressive use before completing the recommended heat cycling process. The first several hundred miles matter. Ignoring break-in procedures can shorten the life of even a perfectly installed gear set.

3. Off-Road Shock Loads

This is one of the most common failures we see on heavily used trail vehicles. A tire leaves the ground and begins rotating under power. The tire then reconnects with a rock, ledge, or dirt surface while still spinning. The sudden shock load is transferred through the axle assembly. Sometimes the pinion gear fails immediately. Other times the impact damages bearings or introduces stresses that lead to failure later. The owner may not experience a problem that day. But the damage has already begun.

Many gear failures blamed on the gear manufacturer actually started with one of the three events that are listed above.