37-Inch Tires for Off-Road Builds: Complete Guide

Everything you need to know about running 37-inch tires — lift requirements, 5.13 regearing, axle upgrades, driveshaft needs, best tire brands, and daily driving reality. Expert guide from Godspeed Off-Road, Sarasota FL.

37-Inch Tires for Off-Road: The Serious Builder’s Choice

When someone rolls into Godspeed Off-Road asking about 37-inch tires, we know we’re talking to a builder who’s thought this through. Going to 37s isn’t a casual tire swap — it’s a commitment to building a genuinely capable off-road machine. The ground clearance, the trail capability, the visual impact — 37-inch tires transform a vehicle in ways that 35s can’t match. But that transformation comes with real engineering requirements and a meaningful investment.

What You Need to Run 37-Inch Tires

A 37-inch tire build touches nearly every part of the drivetrain and suspension. Here’s the complete picture:

Lift Height: 4 Inches Minimum

You need at least a 4-inch lift for 37-inch tires. Some builders push 4.5 inches for extra clearance and better suspension geometry. On Wranglers, flat fenders or high-clearance fenders are common additions to avoid rubbing at full lock and articulation.

  • Jeep Wrangler JK/JL: 4 inches with flat fenders, or 4.5 inches with stock-style fenders. Fender trimming is usually necessary either way.
  • Jeep Gladiator: 4 inches minimum. The longer wheelbase helps with stability but the bed area may need trimming.
  • Ford Bronco: 4 inches with aftermarket fender flares or trimming. The Bronco community has developed good solutions for 37s.
  • Full-size trucks: 4 to 6 inches depending on the platform, cab style, and whether you’re willing to do body work.

Regearing: 5.13 Gears Required

The standard gear ratio for 37-inch tires is 5.13. This puts your highway RPM at approximately 2,090 at 65 MPH — the ideal balance of power and efficiency. Some trail-focused builds opt for 5.38 gears for the extra crawl ratio, accepting slightly higher highway RPM (~2,190). Running 37s on stock or 4.10 gears is not viable — the vehicle will barely be able to merge onto a highway.

Axle Shafts: Upgrade Mandatory

At 37 inches, factory axle shafts become a genuine reliability concern. Chromoly aftermarket shafts for both front and rear axles are strongly recommended — and we’d call them mandatory for the front. The torque loads from 5.13 gears turning 37-inch tires exceed what factory shafts were designed to handle, especially on Dana 30 front axles. RCV, Yukon, and G2 all make quality chromoly shaft sets for common platforms.

Driveshafts: Aftermarket Required

With 4 inches of lift, your factory driveshafts are operating at angles they weren’t designed for. An aftermarket rear driveshaft with a CV or double-cardan joint is a requirement, not an option. Most builds also benefit from an upgraded front CV driveshaft, especially if you’ve lifted beyond 4 inches.

Steering Components

The weight of 37-inch tires — typically 80–90 pounds per tire with wheel — puts significant stress on steering components. Death wobble, wandering, and imprecise steering are common symptoms when factory steering hasn’t been upgraded. A heavy-duty steering stabilizer, upgraded tie rod and drag link, and a beefier track bar should be part of any 37-inch build. See our death wobble repair page for more on steering health.

Best 37-Inch Tire Options

All-terrain:

  • BFGoodrich KO2 (37×12.50R17): Proven reliability, excellent tread life, and strong wet/dry performance. The go-to for daily-driven 37-inch builds.
  • Nitto Ridge Grappler (37×12.50R17): Hybrid tread pattern that performs well on both pavement and trails. Popular for its balance of aggression and highway manners.

Mud-terrain:

  • BFGoodrich KM3 (37×12.50R17): Modern mud-terrain technology with a self-cleaning tread. Reasonably quiet on highway despite its aggressive look.
  • Mickey Thompson Baja Boss (37×12.50R17): Serious off-road tire with competitive heritage. Excellent in rocks, mud, and sand.

Daily Driving with 37-Inch Tires

Let’s be honest about the trade-offs. Daily driving a 37-inch tire rig is absolutely possible — we have customers who do it every day in Sarasota — but it’s different from a stock vehicle:

Fuel economy: With proper 5.13 gearing, expect 13–16 MPG highway on a Wrangler or mid-size platform. Full-size trucks may see 11–14 MPG. This is the reality of spinning heavy, large-diameter rubber.

Parking: Your vehicle is wider and taller. Parking garages may be an issue. Low-ceiling drive-throughs require attention. You’ll learn quickly which spots work and which don’t.

Road noise: 37-inch tires — especially mud-terrains — are noticeably louder on pavement than stock tires. All-terrains are better, but even they produce more road noise than a 33-inch setup. Some owners add sound deadening; most just turn up the radio.

Ride quality: The taller, heavier tire combined with a 4-inch lift changes the ride character. It’s not uncomfortable, but it’s noticeably firmer and more truck-like. Quality shocks (Bilstein 5100, Fox, King) make a significant difference in ride quality at this lift height.

Off-Road Capability with 37s

This is where 37-inch tires earn their investment. The ground clearance increase over 35s is approximately 1 inch at the axle — but the approach, departure, and breakover angle improvements are meaningful on technical terrain. Combined with 5.13 gears in low range, you have the crawl ratio and wheel torque to handle obstacles that would require momentum (and damage risk) on smaller tires.

For Florida off-roading — deep sand, mud, water crossings, and the rock features at places like Hard Rock Off Road Park — 37-inch tires are the entry point for the serious sections. You can run trails at Croom and Morris Bridge on 35s, but the advanced lines at places like Ocala require 37s to be comfortable.

Frequently Asked Questions

What lift do I need for 37-inch tires?

A minimum 4-inch lift, with fender trimming or flat fenders on most vehicles. Some builds run 4.5 inches for additional clearance. The exact requirement depends on your vehicle, wheel offset, and fender situation.

What gear ratio do I need for 37-inch tires?

5.13 gears are the standard recommendation for daily-driven 37-inch builds. Trail-focused rigs may prefer 5.38 gears for the additional crawl ratio, accepting slightly higher highway RPM.

How much does a 37-inch tire build cost?

A complete 37-inch build — lift kit, tires, wheels, regear to 5.13, axle shafts, driveshaft, steering components, and alignment — is a significant investment that varies by vehicle and component choices. We provide detailed build estimates so you know the full scope before any work begins. We can also stage the build over multiple visits if needed.

Are 37-inch tires worth it over 35s?

It depends on your priorities. If off-road capability is a primary goal and you’re willing to accept the daily-driving trade-offs (lower MPG, more road noise, higher investment), 37s deliver meaningfully more capability. If your rig is 80%+ daily driver, 35-inch tires offer a better balance. There’s no wrong answer — it’s about what you need from your vehicle.

Do I need to upgrade my axles for 37-inch tires?

The axle housings (Dana 44s) are typically adequate for 37s on street and moderate trail use. The axle shafts, however, should be upgraded to chromoly aftermarket units — especially the front axle. Dana 30 front axles should be upgraded or replaced entirely for 37-inch tire use.

Ready for a 37-Inch Build?

A 37-inch tire build is the mark of a serious off-road vehicle. We’ll plan every component, every modification, and every detail so your build works as a complete system — not a collection of parts bolted together. Let’s build something right.

Call Dan at (941) 706-0071 or visit us at 2858 Clark Road, Sarasota, FL.