What Rubber Fits?
Q I have a (any make and model of 4x4 here), and I am ready for some bigger tires. What tires will fit on my 4x4?
A Bigger, more aggressive tires are the epitome of the off-road vehicle. A winch is cool, bright lights are neat, and lower gearing is important, but nothing gives your truck that “I’m ready to wheel” look like big rubber. But looks and performance are two different things. You must decide what you want to do with your 4x4, what type of tires you want (aggressive mud-terrains or more streetable all-terrains), how much you are willing to invest, and how much tire you want.
I usually recommend a mud-terrain tire for off-road use. They have drawbacks in that they are usually more expensive and can have a shorter lifespan than all-terrains, but they work much better over a larger variety of terrain and often have much stronger tread and sidewall construction.
At this point I’m going to send you to our website, 4wheeloffroad.com, to find two specific pages. The first is “How to Measure for Bigger Tires” from our Feb. ’11 issue (“Time, Tires & Tape”). This has a step-by-step procedure to help you determine exactly how much taller and wider a tire you can stuff under your 4x4 as it sits. The next page is the “4x4 Off Road Truck Tire Fitment Guide,” which Feature Editor Ali Mansour wrote for our Nov. ’08 issue (“Just a Guide”). This is a rough guide to help you narrow in on what tires will fit with a certain amount of lift.
level, lift, or trim?
Q OK, I know I can fit bigger tires on my (any make and model of 4x4 here), but I’m still confused. I have heard I need either a body lift, a suspension lift, or to trim. What does this all mean?
A Yes, bigger tires often need clearance. This is to prevent the tires from rubbing the body or frame while you’re driving or under full compression of the suspension. One of the simplest and most common upgrades is a leveling kit. Many 4x4s come from the factory with a slight rake to the body, so if you add a leveling kit (usually a spacer above the front suspension coil or strut) the truck will sit level and can usually clear a slightly taller tire.
Another spacer type of lift is a body lift, but they only work on 4x4s that have body-on-frame construction. Where the body bolts to the frame, there are usually small bushings to keep road noise out of the cabin. Body lifts increase the size of these bushings, in effect lifting the body slightly off the frame a few inches. Body lifts can require lengthening or relocating parts like brake lines and shifter or steering columns that run from the body to the frame. I like to see no more than 2 inches of body lift for off-road use. Anything more than that results in long mounting bolts and unsafe shifting possibilities between the body and frame.
The next type of lift is a suspension lift. The 4x4’s suspension is the spring that supports the body and frame over the axles. A suspension lift uses a taller coil spring, an arched leaf spring, or lower mounting points to raise the vehicle. I like the suspension lift, as it not only raises the body but also the frame to give better ground clearance.
As with anything, there can be a problem with too much suspension lift. Off-road, it is usually good to have a low center of gravity. Oftentimes any suspension lift over 8 inches can harm vehicle handling. Some extremely tall lifts have very stiff springs and can reduce wheel travel, making for a rough ride. Imagine your 4x4 is a pyramid. The taller you go, the wider you should be for more stability. But this can also have issues, as you may eventually need custom axlehousings and you might not be able to fit down the road or trail.
Trimming is when you cut or trim fender openings and bumpers to clear bigger tires. Trimming is a personal decision that many 4x4 owners are not comfortable with, while others are ready and willing to cut with abandon. If your truck is old and rusty around the wheel openings, then trimming may not seem so bad. If it’s brand-new and has a hefty monthly payment, then you may not be as keen on firing up the plasma cutter or Sawzall. I have often found that a lift kit will say it can clear one size tire—say, 35s with a 6-inch lift—but you can often go up 1-2 inches in tire size by slightly trimming the back of the front bumper or by pounding flat the inner-fender pinch seams.
My personal preference is as low a lift as possible, maybe a 1-inch body lift max and some slight fender trimming to clear as big a tire as possible.