I've been getting a ton of questions about running 295 70r18 on stock trail boss setups lately, and it honestly makes a lot of sense why this specific size is so popular. If you're driving a Silverado or Sierra Trail Boss, you already have that factory 2-inch lift, which gives you a bit more breathing room than a standard RST or LT. But the stock tires usually look just a little too small for the wheel wells. Moving up to a 295/70R18 is basically the "sweet spot" for many owners who want a beefier look without having to shell out thousands for a bigger aftermarket lift kit.
The short answer is yes, they fit, but there's a little more to the story than just slapping them on and driving away. Depending on how picky you are about a tiny bit of noise at full lock or if you're willing to do a five-minute trim job, your experience might vary.
Why the 295 70r18 is the go-to size
When you look at the math, a 295/70R18 comes out to be roughly 34.3 inches tall and about 11.6 inches wide. Compare that to the stock 275/65R18 (which is about 32 inches) or the 275/70R18 (about 33 inches) that comes on some models, and you're talking about a significant jump in presence.
It's that extra inch and a half of height and the added width that really transforms the truck. It fills out the wheel arches perfectly. It makes the Trail Boss look like it should have from the factory—aggressive, sturdy, and ready for more than just a grocery run. Plus, because it's a 70-series tire, you still have plenty of sidewall. That's great for ride quality and even better if you actually plan on airing down for some weekend trail riding.
The reality of fitment on a stock setup
Here is where we get into the nitty-gritty. If you are running 295 70r18 on stock trail boss wheels, you are generally in a better spot than someone with aftermarket wheels. The factory wheels have a high positive offset, which keeps the tire tucked inside the fender. This is actually your best friend when trying to clear a larger tire on a stock suspension.
If you keep the stock rims, you will likely clear the actual metal fenders just fine. However, the most common "problem" area is the plastic wheel well liner and the brackets for the front mud flaps. At full lock—meaning when you turn the steering wheel all the way to the left or right—you'll probably hear a little bit of a rrrt sound. That's the tire tread catching on the plastic liner or the mud flap.
For most guys, this isn't a dealbreaker. It usually only happens when you're backing out of a driveway or parking in a tight spot. If you can live with that, you can run them 100% stock. But if you're like me and every little noise drives you crazy, you're going to want to do some minor adjusting.
The "No-Cut" modifications
If you find that your 295 70r18 on stock trail boss setup is rubbing more than you'd like, you don't necessarily have to pull out a Sawzall. The modern GM trucks have a bracket behind the front mud flap that is notorious for getting in the way.
A very common fix is the "mud flap delete" or just swapping in some low-profile aftermarket flaps. Some people also use zip ties to pull the felt wheel well liner back an inch or so. It sounds "backyard mechanic," but it's hidden behind the tire and it works perfectly. By pulling that liner back toward the frame, you can often eliminate 90% of the rubbing issues at full lock.
Now, if you decide to go with aftermarket wheels with a lower offset (meaning they stick out further), all of this goes out the window. A 0 offset or a negative offset wheel will push that 295 tire right into the back of the fender flare and the front bumper valance. If you want to keep things simple, stick with the factory wheels.
Performance and gas mileage hits
We have to talk about the trade-offs, because nothing is free when it comes to truck mods. Moving to a 295 70r18 on stock trail boss means you are adding a lot of unsprung weight. Most tires in this size are E-rated, which means they have thicker, heavier sidewalls designed for towing and heavy-duty use.
You're likely going to see a drop in your MPG. On average, most guys report losing about 1.5 to 2 miles per gallon. The truck might also feel a little "slower" off the line because it takes more energy to get those heavier tires spinning.
Your speedometer will also be off by a few miles per hour. Since the tire is taller, your truck thinks it's traveling a shorter distance per revolution than it actually is. When your dash says 65 mph, you might actually be doing closer to 68 or 69 mph. It's not a huge deal, but it's something to keep in mind when you're passing a speed trap on the highway. You can fix this with a plug-in calibrator, but many people just learn to live with the "mental math."
Ride quality and handling
Surprisingly, the ride quality usually stays pretty decent. Since you're staying with an 18-inch wheel, you have a lot of rubber between the rim and the road. This helps soak up the potholes and gravel chatter. However, because most 295s are 10-ply (Load Range E) tires, the ride will feel a bit firmer than the "squishy" P-rated tires that often come from the dealer.
On the highway, you might notice a bit more hum. This depends entirely on the tread pattern you pick. A dedicated Mud-Terrain (MT) is going to howl, while a hybrid or All-Terrain (AT) like the Nitto Ridge Grappler or the Falken Wildpeak AT3W is going to be relatively quiet. In my experience, the Trail Boss cabin is pretty well-insulated, so even a moderately aggressive tire isn't going to ruin your ability to have a conversation.
Is a leveling kit necessary?
A lot of people ask if they should add a leveling kit on top of the factory Trail Boss lift to clear the 295 70r18 on stock trail boss combo. You can, but you need to be careful. The Trail Boss already has upgraded CV axles and upper control arms to handle its factory lift. If you add another 1.5 or 2 inches on top of that, you are starting to push the angles of your suspension components into a "danger zone" where things might wear out prematurely.
If you just want to clear the tires, a small 0.5-inch or 1-inch spacer might help, but most people find that with the stock wheels and a tiny bit of plastic trimming, the leveling kit isn't strictly necessary. It really comes down to whether you want that perfectly level look or if you don't mind the slight factory rake.
Final thoughts on the setup
At the end of the day, running 295 70r18 on stock trail boss trucks is one of the best bang-for-your-buck upgrades you can do. It completely changes the stance of the vehicle and gives you a lot more confidence when you head off the pavement.
Yes, you might have to zip-tie a liner or remove a plastic bracket. Yes, you'll spend a bit more at the gas pump. But when you walk out into the parking lot and see your truck looking that much meaner, you probably won't care about a lost mile per gallon. It's a tried-and-true setup that thousands of owners are running daily. Just pick a good set of tires, keep an eye on your clearances during the first few turns, and enjoy the new look of your rig.