40-Inch Tires: The Ultimate Off-Road Build
Running 40-inch tires is the pinnacle of off-road vehicle modification. This isn’t a casual upgrade — it’s a full-commitment build that transforms your vehicle into a purpose-built machine capable of conquering terrain most rigs can’t even approach. At Godspeed Off-Road in Sarasota, we build 40-inch rigs for enthusiasts who demand maximum capability and aren’t afraid of the investment it takes to get there.
Which Vehicles Can Run 40-Inch Tires?
Not every platform is suited for 40-inch tires. The vehicles that handle this tire size best are those with solid axle platforms and strong aftermarket support. The Jeep Wrangler is the most common platform we build to this spec, thanks to its solid axles, body-on-frame construction, and massive aftermarket ecosystem. Other candidates include full-size trucks with solid front axles (like the Ford F-250 Super Duty and RAM 2500), though these builds are less common and require even more custom work.
What Does a 40-Inch Build Require?
A 40-inch tire build touches every major system on your vehicle. Here’s what’s involved:
- Lift Kit: Minimum 6 to 8 inches of suspension lift, typically a long-arm or coilover system. Spacer lifts and budget kits are not appropriate at this level.
- Regearing: 5.38 gears are the minimum recommendation. Without regearing, your vehicle will be nearly undrivable — sluggish acceleration, inability to maintain highway speeds, and severe transmission strain.
- Axle Upgrades: Factory axles are typically not strong enough. Dana 60 (or equivalent) axle assemblies with chromoly shafts, aftermarket housings, and heavy-duty u-joints are standard for a 40-inch build.
- Steering: High-steer or crossover steering conversion to accommodate the larger tires and increased lift height. Factory steering geometry doesn’t work at this level.
- Brakes: Minimum 13-inch rotors with upgraded calipers. The increased rotational mass of 40-inch tires demands significantly more stopping power than stock brakes can deliver.
- Driveshafts: Upgraded driveshafts with proper u-joint angles for the increased lift height. CV-style driveshafts are preferred for their ability to handle steeper angles.
- Body Modifications: Aftermarket fenders or aggressive body cutting to clear 40-inch tires at full articulation. Bumper upgrades are typically part of the package.
40-Inch Tire Brand Options
The selection of 40-inch tires is more limited than smaller sizes, but the options that do exist are built for serious off-road duty:
- BFGoodrich KM3 — The Mud-Terrain T/A KM3 in 40-inch sizes is a proven performer in rock crawling and extreme off-road conditions.
- Nitto Trail Grappler — Aggressive mud-terrain design with surprisingly good highway manners for a tire this size.
- Mickey Thompson Baja Boss — Race-heritage tread design with exceptional grip in loose and rocky terrain.
- Maxxis Trepador — A dedicated rock-crawling tire that excels in competition-level terrain.
Frequently Asked Questions
How much does a complete 40-inch tire build cost?
A 40-inch build is a significant investment that varies widely depending on the platform, component choices, and what work has already been done to the vehicle. Because every build at this level is custom, we prefer to discuss specifics in person. Call us at (941) 706-0071 for a consultation — we’ll walk through the options and help you plan a build that matches your goals and timeline.
Can I daily drive a truck with 40-inch tires?
Technically yes, but it requires commitment. A properly built 40-inch rig with quality suspension, correct gearing, and well-chosen tires can be driven on the street. However, fuel economy will decrease significantly (expect 10-12 MPG or less), parking becomes more challenging, and the ride character is fundamentally different from a stock vehicle. Most 40-inch builds serve as dedicated trail rigs or weekend warriors rather than daily commuters.
Is regearing mandatory with 40-inch tires?
Absolutely, without exception. Running 40-inch tires without regearing (5.38 minimum) makes the vehicle nearly undrivable. The transmission will hunt constantly, acceleration will be dangerously slow, and you’ll destroy your drivetrain components in short order. Regearing is not optional at this tire size — it’s a fundamental requirement of the build. Learn more about regearing.
How long does a 40-inch build take?
A complete 40-inch build typically takes 2 to 4 weeks in the shop, depending on parts availability and the scope of modifications required. We plan these builds carefully in advance to ensure all components are on hand before we start disassembly. Rush jobs at this level lead to mistakes — we’d rather take the time to do it right.
Ready for the Ultimate Build?
A 40-inch build is the ultimate expression of off-road capability. At Godspeed Off-Road, we have the experience and expertise to plan and execute builds at this level — from initial consultation through final trail testing. If you’re serious about running 40s, let’s talk.
Call us at (941) 706-0071 or visit us at 2858 Clark Road, Sarasota, FL 34231.