Part 2: Tires and Wheels—Where the Rubber Meets the Road (and Rock)
Welcome back to the build! If Part 1 was about setting the stage with the right lift kit Part 2 is about selecting the engine's power band: the tires and wheels. These are the components that actually translate your Jeep’s torque into forward motion and are, without a doubt, the most significant factor in determining your vehicle’s off-road grip, on-road comfort, and overall visual presence.
The Core Decision: A/T vs. M/T vs. R/T
Before you obsess over the size (we’ll get there), you need to choose the type of tire based on where you spend 80% of your driving time.
1. All-Terrain (A/T)
The A/T tire is the daily-driver king. It features a dense tread pattern, often with smaller, tightly packed blocks, making it quiet, comfortable, and long-wearing on asphalt.
- The Down-to-Earth Takeaway: An A/T is excellent for fire roads, sand, and light snow, and it handles wet pavement safely. If your Jeep is primarily a commuter that sees mild trail action, this is your choice. You’ll appreciate the long tread life and the ability to hold a conversation without screaming over tire noise.
2. Mud-Terrain (M/T)
The M/T tire is built for serious abuse. It has large, aggressive, widely spaced tread blocks designed to dig into and clear out mud, clay, and soft dirt. They often feature reinforced sidewalls for sharp rocks.
- The Down-to-Earth Takeaway: M/Ts offer legendary grip when traction is scarce, but they are loud on the road, wear out faster, and are substantially heavier. If you spend most of your weekends deep in the backcountry, the trade-off is worth it. But be honest about your usage—many weekend warriors buy M/Ts for the look and regret the highway drone.
3. Rugged-Terrain (R/T)
The R/T, or Hybrid-Terrain, is a modern compromise. It combines the aggressive, open-tread look of an M/T on the shoulders with the tighter, quieter center tread of an A/T.
- The Down-to-Earth Takeaway: The R/T is ideal for those who want the tough aesthetic and moderate trail performance without the headache of daily M/T road noise. It’s often the best blend of on-road civility and off-road capability for the average builder.
The Numbers Game: How Big is Too Big?
Once your lift is installed, you need to match your tire size to your suspension height. This is where the geometric limitations of the factory drivetrain come into play. Tires are measured in three sizes (e.g., 35x12.50R17):
- 35 (Height in inches): The overall diameter of the tire.
- 12.50 (Width in inches): The tread width.
- 17 (Wheel diameter in inches): The diameter of the wheel it mounts to.
Lift Height
Common Tire Size Goal
Drivetrain Component Impact
2.5" - 3"
33" or 35"
Minimal impact, but may need flat fender flares for 35s. Stock gears are manageable but sluggish.
3.5" - 4"
35" or 37"
Requires Re-gearing. Places significant stress on factory axles and joints. Brake performance suffers.
4.5" +
37" or larger
Requires axle reinforcement/replacement, heavy-duty brakes, and a full long-arm suspension.
The Critical Need for Re-gearing
Lifting and installing tires larger than 33 inches dramatically changes your effective final drive ratio. Your engine now has to work much harder just to spin those massive, heavy tires.
- The Down-to-Earth Takeaway: If you run 35s or larger on stock gears (like 3.73 or 4.10), your Jeep will feel sluggish, the transmission will constantly hunt for the right gear, and your engine will run hotter. You must re-gear the axles (install new, numerically higher ring and pinion gears) to bring the power and RPM back into the engine's optimal range. This is an expensive, mandatory upgrade for safety, performance, and drivetrain longevity.
The Wheel: Backspacing and Offset
The wheel is more than just a mounting point; it dictates your vehicle’s stance and, more importantly, provides the clearance you need to turn those huge tires without rubbing the frame or suspension.
- Offset: The distance (in millimeters) from the center line of the wheel to the hub mounting surface. A negative offset pushes the wheel out from the Jeep, widening the track.
- Backspacing (The Key Number): This is the distance from the wheel's inner lip to the mounting surface. For most lifted Jeeps running 35-inch or 37-inch tires, you typically want a backspacing in the 4.5" to 4.75" range. This number pushes the tire far enough out to clear the control arms and sway bar links while turning.
If you skip correcting backspacing, your new large tires will guarantee rubbing issues, potentially damaging your expensive rubber and suspension components.
Beadlocks: When You’re Serious About Airing Down
For dedicated off-roaders who need extreme traction, beadlock wheels are the ultimate upgrade.
- The Difference: A beadlock uses an external ring that physically clamps the tire bead (the edge of the tire) to the wheel rim. This allows you to safely lower tire pressure (air down) to single digits (5-8 PSI) for maximum contact patch and grip on rocks and sand, without the risk of the tire coming off the bead.
- The Reality: Beadlocks are heavy, expensive, and often require more maintenance. Critically, some jurisdictions consider them "not street legal" because they can be difficult to balance and inspect, so check local laws before committing.
Finalizing the Build: Budgeting for Five
When budgeting for tires and wheels, remember that your spare tire is no longer optional. A stock spare won't fit on your upgraded carrier, and it certainly won't help you on the trail or the highway if you're running 37-inch tires.
Always buy a set of five matching tires and wheels.
Finally, the added weight of larger tires (a 35-inch tire and wheel combo can weigh 100+ lbs) places enormous stress on your tailgate and spare tire carrier. Factory carriers are simply not designed to handle that kind of weight long-term. Budget for a reinforced tailgate hinge or an aftermarket bumper-mounted tire carrier to prevent structural failure.
Matching your tires and wheels to your lift is a delicate balancing act of capability, geometry, and cost. Get the specs right, and you'll have a Jeep that not only looks incredible but performs flawlessly wherever you point it.
Add comment
Comments