Upgrading to 37-inch tires is a major step in any truck or Jeep build. The jump in size delivers increased ground clearance, improved obstacle approach angles, and a commanding presence both on and off the road. However, fitting 37s is not as simple as bolting them on. This size upgrade requires thoughtful planning and supporting modifications to maintain drivability, reliability, and safety.
Before committing to such a large tire, it’s important to understand the suspension, steering, and structural upgrades required. Many builds begin with a properly engineered jeep lift kit, but lift height alone does not guarantee proper fitment or performance. Let’s break down what modifications are typically needed when moving to 37-inch tires.
In This Article:
Lift Height Requirements
The most obvious requirement for running 37-inch tires is additional lift height. Larger tires increase overall diameter significantly compared to stock or even moderate upgrades like 35 in tires. That extra height must be accommodated with adequate clearance during steering lock and full suspension compression.
For most Jeeps and mid-size trucks, a lift of at least 3.5 to 4 inches is typically recommended to clear 37-inch tires properly. Some full-size trucks may require slightly less depending on factory wheel well dimensions, but clearance must always be tested under articulation—not just while parked.
It’s important to remember that lift height affects more than appearance. Raising the suspension alters control arm angles, track bar geometry, and driveline alignment. Installing a complete lift kit designed specifically for your vehicle ensures that critical components remain within safe operating angles.
In addition to suspension lift, trimming or modifying fenders may be necessary. Even with adequate vertical clearance, wide tires can contact fender liners during turning or off-road articulation. High-clearance fenders are common upgrades for builds running 37s.
Wheel offset also plays a role. Incorrect backspacing can push the tire too far inward or outward, increasing the likelihood of rubbing against suspension components or body panels.
Steering and Suspension Reinforcement
Once you move into the 37-inch tire range, reinforcing steering and suspension components becomes essential. Larger tires are significantly heavier than stock options, increasing rotational mass and placing additional strain on critical systems.
Tie rods, drag links, ball joints, and steering boxes must handle greater stress during turns—especially in low-speed off-road scenarios. Many builders upgrade to heavy-duty steering components to prevent premature wear or failure.
Axles are another major consideration. Depending on your vehicle, factory axle shafts may not be designed to handle the torque load associated with 37-inch tires. Upgrading to stronger axle shafts or even complete axle assemblies may be necessary for aggressive trail use.
Brake performance should also be evaluated. Larger tires require more force to stop effectively. Upgraded brake pads, rotors, or big brake kits can help restore stopping performance and maintain safety.
Suspension components like control arms and track bars often need reinforcement as well. Adjustable control arms allow proper alignment after lifting, while heavy-duty track bars help maintain axle centering under load.
Daily driving comfort may also change with larger tires. Added weight can impact steering feel and responsiveness. Installing a quality steering stabilizer can help manage vibration and maintain control.
Finally, practical upgrades such as side steps for trucks may become necessary. With increased ride height from both lift and larger tires, entry and exit can become more challenging. Side steps improve accessibility without compromising the aggressive look of your build.
Drivetrain and Gearing Considerations
Running 37-inch tires effectively changes your vehicle’s gearing. Larger diameter tires reduce effective gear ratio, which can lead to sluggish acceleration and increased strain on the transmission.
Re-gearing is often recommended when moving to 37s. Proper gear ratios help restore lost torque and improve drivability. Without re-gearing, your engine may work harder than intended, especially during highway driving or towing.
Driveshaft angles may also change with taller lifts. In some cases, upgraded driveshafts or slip yoke eliminators are required to prevent vibration and long-term wear.
Fuel economy is another factor to consider. Larger, heavier tires increase rolling resistance, which can reduce efficiency. While many enthusiasts accept this trade-off for improved capability, it’s important to plan accordingly.
Long-Term Maintenance and Real-World Use
Upgrading to 37-inch tires isn’t just about initial installation—it’s about long-term durability. Larger tires increase wear on wheel bearings, ball joints, and suspension bushings. Regular inspections and maintenance become even more important.
Alignment should be checked after installation and monitored periodically. Proper alignment reduces uneven tire wear and helps maintain stable steering response.
For trucks and Jeeps that serve as daily drivers, balancing off-road capability with road comfort is essential. While 37-inch tires offer impressive performance in rugged terrain, they require thoughtful supporting modifications to ensure safe and reliable daily use.
Conclusion
Installing 37-inch tires on a truck or Jeep requires more than just additional lift. Proper suspension height, reinforced steering components, upgraded brakes, and appropriate gearing all play critical roles in building a safe and capable setup.
With the right supporting modifications, 37-inch tires can dramatically enhance off-road performance and visual presence. But skipping necessary upgrades can lead to premature wear and drivability issues.
By planning carefully and reinforcing key systems, you can enjoy the benefits of 37-inch tires while maintaining long-term reliability and confidence—on the road and far beyond it.
