If you're looking into a leveling kit trail boss with 35 inch tires, you've probably realized that while the factory stance is okay, it's not quite "finished." The Chevy Silverado Trail Boss (and its GMC AT4 cousin) comes from the factory with a two-inch lift, which is great for a stock truck, but it still has that annoying nose-down rake. Most guys want that perfectly level look, and more importantly, they want to fill those wheel wells with some meatier rubber.
The jump to 35s is the gold standard for half-ton trucks these days. It gives the truck a much more aggressive profile and actually provides some functional ground clearance for the dirt. However, stuffing 35-inch tires under a Trail Boss isn't always as simple as just bolting them on and driving away. There's a bit of physics and geometry involved that you'll want to wrap your head around before you drop a couple of grand on parts and labor.
Why the Trail Boss is a bit different
The first thing to understand is that the Trail Boss isn't a standard Silverado. Since it already has a factory two-inch lift, adding a "standard" two-inch leveling kit on top of that actually puts you at four inches of lift over a base model truck. That sounds awesome in theory, but it changes the angles of your CV axles and your upper control arms (UCAs) significantly.
If you just throw a cheap spacer on top of the factory struts, you might find that your ride quality goes down the drain. The truck can feel stiff, and you'll likely hear some popping sounds when you turn the wheel or hit a bump because the UCAs are hitting the springs or the ball joints are maxed out. If you're planning on running a leveling kit trail boss with 35 inch tires, you really need to consider how that extra height affects the rest of the front end.
Choosing the right leveling height
Most people find that a 1.5-inch to 2-inch leveling kit is the "sweet spot" for the Trail Boss. This usually levels the truck out perfectly with the rear. If you go much higher than two inches in the front, the truck starts to look "squatted" (nose-high), which most people try to avoid unless they're into that specific style.
There are two main ways to go about this. You can do the top-mount spacers, which are affordable and easy to install, or you can go with replacement struts or adjustable coil-overs. If you have the budget, the replacement struts—like those from Bilstein or Eibach—are almost always the better choice. They actually improve the ride rather than just changing the height, and they handle the extra weight of 35-inch tires much better than the factory setup.
Will 35-inch tires actually fit?
This is the million-dollar question. The short answer is: yes, but with a "but."
If you try to run a true 35x12.50 tire on stock Trail Boss wheels with just a leveling kit, you're going to run into some rubbing issues. The most common spot for rubbing is on the frame or the sway bar when you're at full lock (turning the steering wheel all the way). It also likes to catch the back of the wheel well liner and those plastic mud flaps that Chevy decided to bolt on there.
To make 35s work without a headache, many owners opt for a "skinny 35," such as a 285/75R18 or a 295/70R18. These tires are roughly 34.5 to 35 inches tall but are a bit narrower than a traditional 12.50-wide tire. This extra narrowness helps clear the internal components when you're turning. If you absolutely must have the wide 12.50 look, you're probably looking at some minor trimming.
The importance of wheel offset
Wheel offset is the "make or break" factor for a leveling kit trail boss with 35 inch tires. If you stick with the factory wheels, the high positive offset keeps the tire tucked inside the fender. This is good for keeping the side of your truck clean, but bad for rubbing on the frame.
If you move to an aftermarket wheel with a lower offset (like a +18, +1 or even a 0 offset), you push the wheels outward. This clears the frame but creates a new problem: now the tire wants to hit the metal at the back of the wheel well when you turn. This is where the "NorCal Mod" or some basic plastic trimming comes into play. You basically have to push back the liner or trim a tiny bit of the metal bracket behind the liner to give the tire a clear path to swing.
Don't forget the Upper Control Arms
I mentioned this earlier, but it's worth its own section. When you add a leveling kit to a Trail Boss, your factory upper control arms are pushed to their limit. The angle of the ball joint becomes pretty steep, which can lead to premature wear. Even worse, the factory stamped-steel arms aren't exactly "beefy."
If you're serious about this setup, especially if you plan on taking the truck off-road, upgraded UCAs are a smart investment. Brands like Readylift, Rough Country, or Cognito make arms specifically designed for leveled trucks. They have a different angle built into the ball joint cup that restores your factory geometry and allows for more "droop" travel. It makes the truck feel much more planted and saves you from a ball joint failure down the road.
Real-world performance and MPG
Let's talk about the stuff no one likes to hear: your gas mileage is going to take a hit. Those 35-inch tires are heavy. You're increasing the rotating mass significantly compared to the stock 32 or 33-inch tires. Most guys report a drop of 2 to 4 miles per gallon after switching to a leveling kit trail boss with 35 inch tires.
The truck will also feel a little "sluggish" off the line. The 5.3L or 6.2L V8 engines have plenty of power, but the larger tire diameter effectively changes your gear ratio. It's not a dealbreaker, but you'll notice the transmission shifting a bit differently. Some people choose to use a programmer or a Pulsar LT module to recalibrate the speedometer and adjust the shift points, which helps the truck feel more like its old self.
The "Look" is worth it
Despite the trimming and the slight drop in MPG, there's a reason why this is one of the most popular mods for the Silverado. A leveled Trail Boss on 35s looks exactly how the truck should have come from the factory. It gives it a commanding presence on the road and makes it look like it can actually handle the "Trail Boss" name.
When you pull up next to a stock Silverado, the difference is night and day. The leveled stance removes that "stinkbug" look where the rear is sticking up in the air, and the 35s fill the gaps perfectly without looking like you're trying too hard with a massive six-inch lift.
Maintenance and long-term care
Once you've got your leveling kit trail boss with 35 inch tires installed, you can't just forget about it. Big tires put more stress on your steering rack, wheel bearings, and brakes. You'll want to make sure you're rotating those tires every 5,000 miles to prevent uneven wear, especially with aggressive mud-terrain or all-terrain treads.
Also, get a high-quality alignment done immediately after the install. A lot of shops will just "toe it and go," but you want to make sure your caster is set correctly so the truck doesn't wander on the highway.
At the end of the day, building a truck is all about personal preference and finding the right balance between form and function. Adding a level and 35s to a Trail Boss is a classic move that, when done right, makes for one of the best-looking trucks on the road today. Just do your homework on the offset, keep an eye on your UCAs, and be ready to do a little trimming to make everything clear.