Putting The Urban Back In A 1991 4×4 Suburban

Not long ago, we took our 1991 Chevrolet Suburban project and performed an LS swap. The old truck came from the factory with a throttle-body-injected (TBI) 350 Chevy, rated at a minuscule 210 horsepower, and while we knew that switching to a more modern 440 horsepower powerplant would help the ‘Burbs drivability, we didn’t realize how much more we would enjoy using the heavyweight. 

We stopped by 4Wheel Performance to get our new tires and wheels mounted and balanced.

Since the swap, this now 30-year old vehicle has become one of our primary modes of transportation, as we use it daily. The only problem is that the 35×12.5×15-inch mud-terrain tires that were once tolerable on short commutes are no longer manageable. Call us old, but the cool “waaa-waaa-waaa” noise the tires make driving down the highway leaves a lot to be desired. You can’t talk to the co-pilot on a road trip, listen to the radio, or even hear yourself think. The good news is that a new set of tires can remedy this problem. Sure, we could have just put new tires on the “old school” 15-inch wheels, but the wheels are pretty beat due to off-roading. So, the hunt was on for a new set of tires and wheels for the Suburban. The only problem is, there are so many choices nowadays, with thousands of options to choose from, that it’s hard to choose just one. 

With a budget in mind, billet wheels were undoubtedly out of the question, and we didn’t want anything larger than 20-inches either. Another concern is buying a quality tire and wheel, so we started our search with Mickey Thompson tires and Weld. Both of these companies have an exemplary reputation in the automotive aftermarket industry, and make great products. 

Why So LOUD?

Since we’ve already tried mud-terrain tires for daily driving, we knew that wasn’t the direction to go….  we needed something quieter on the road but still aggressive enough for the off-road elements. We reached out to Jason Moulton, Senior Product Development Manager of Mickey Thompson Tires, to help us figure out the best solution. After listening to us ramble about our needs Moulton recommended the Mickey Thompson Baja ATZp3s. Our next question was, is the ATZ quieter than a mud-terrain tire, and why? 

In this image, you can see the difference between the two tread designs. The Mickey Thompson ATZp3 tire on the left allows less air between the tread, making it quieter at speed. Our mud terrains on the left allow more air in, making them loud on the highway.

Moulton said, “Yes. One component of tire noise is the amount of air that is being pumped or traveled through the tire design. Tires having more void, common to mud terrains, allow more air to travel through the design, resulting in more noise. For comparison sake, the Baja ATZp3 has about 12-percent less road surface void than the Baja MTZp3. That does not necessarily mean it is 12-percent quieter, but it illustrates the difference.” 

So now we know why our mud-terrain tires were so loud after looking at them: the void between the tread is almost as large as the tread itself, resulting in the unbearable noise level at 75 mph on the highway. 

Mickey Thompson Baja ATZp3 

While Mickey Thompson considers the Baja ATZp3 an “all terrain” tire, some in the market consider it more of a hybrid, between a traditional all-terrain and mud-terrain. 

“The Baja ATZp3 shares PowerPLY construction with angled third ply used in the popular Baja MTZp3 — this gives the Baja ATZp3 the same puncture resistance as our popular mud tire, with the added benefit of quicker steering response and handling under heavy loads. The tires have a Silica reinforced tread cap-stock for long-life, excellent wet traction, handling, and braking on-road, and superior cut and chip resistance off-road. The large surface area tread elements provide you with all-terrain-like handling characteristics, while the wide voids give mud-terrain-like off-road traction,” explained Moulton.

The Baja ATZp3 is an excellent tire with the carcass and Siderbiters of a mud tire combined with an all-terrain tread.

Since the Baja ATZ p3 is much closer to a conventional all-terrain tire from a noise perspective, this tire seemed like the perfect choice for our vehicle. The only problem now was to choose a tire size. Since the Suburban is set up for 35-inch tall tires, we decided on the 35×12.5×20 Baja ATZp3, after briefly considering the taller 37-inch size. But since these tires will be 60-percent street and 40-percent offroad, larger tires didn’t make sense. With the Mickey Thompson tires on the way, we turned our attention to the wheels. 

Weld’s Rotary Formed Off-Road Wheels

Weld recently introduced a new line of wheels geared for the off-road enthusiast. Its rotary-formed wheels offer several different styles to choose from, with a quality wheel that starts at only $255. While we were scrolling through Weld’s website, the Chasm W103 caught our eye. This wheel is a split eight-spoke design that offers bold looks with a glossy black finish and milled accents. We could tell that fitment with this wheel wasn’t going to be a problem, because the Chasm is available in five, six, and eight-lug patterns and multiple offsets. We added the Chasms to our cart in a 20×10-inch, six-lug configuration, but before we hit the checkout button, we had some questions for Vincent Wong, Vice President of Product Development at Weld.

Weld now offers a new line of off-road wheels at an affordable price with several different styles to choose from.

Rotary Formed Perfection

The Rotary Formed process is a unique solution to a common problem: making light and strong wheels. The process starts with a low-pressure type casting which uses a unique machine that spins the casting, heats the outer portion, then uses steel rollers pressed against the rim area to pull the rim to its final width and shape. The heat, pressure, and spinning of this process give the wheel strength to a forged wheel. This unique process also translates to 15-percent less weight when compared to a standard cast wheel. 

We liked the looks of Weld’s Chasm wheel and thought the split-spoke design would complement the Suburban.

“As the rotary-formed process pioneer, we’ve been looking to incorporate the technology into the offroad market. With our technology, we have been able to optimize our designs and target them for specific trucks,” Wong explained. “This allows us to make wheels on average five pounds lighter than the competition without sacrificing strength. The rotary forming process also creates a more accurate and straighter weight, requiring fewer wheel weights to balance.”

Weld Chasms 

The Weld Chasm was the second wheel to be released in WELD’s Off-Road rotary formed lineup. Wong said, “The team was looking for a split-spoke sporty truck wheel that would look good on any truck. The side milling and Weld Offroad branding on the lip are nice finish touches that break up the black and give the design great depth and contrast.”  

Currently, WELD offers eight designs, with more on the way for the second quarter of 2021. The wheels are built in popular widths, offsets, and truck fitments, and are generally ready to ship out the same day.

Mounted and Balanced

With our new tires and wheels loaded up, we headed down to 4 Wheel Performance in Wichita Falls, Texas to get the set mounted and balanced. This process was nothing out of the normal, but we were impressed at how balanced the wheel and tire combination was. We only had to add a couple of ounces of weight to get the tires and wheels in sync. This was not the case with the old 15-inch setup. It looked like they had a pound or two on each wheel with some of the weights coming off. 

Jesse Smith of 4Wheel Performance mounted and balanced our new tire and wheel combo for the Suburban.

With the new rollers mounted on the Suburban, we ran into a bit of snag. The center caps would not go on the fronts due to the locking hubs. All we had to do was use a die grinder and open the hole up, allowing the caps to slide over the hub. Jeremy Nichols, Shop Manager of 4 Wheel Performance took care of this for us, before he torqued the new tire and wheel combination on the Suburban. 

With the ‘Burb in the 4WP parking lot, we took a minute to check out the new 20-inch setup. And to be honest, we were a little nervous about putting a 20-inch tire and wheel on the Squarebody, and we were hoping it wasn’t a mistake. But after looking at it, we think the Weld Chasm’s and 35×12.5×20-inch Mickey Thompson’s look stellar. And our thoughts have been confirmed with cash offers on the truck and countless thumbs up as we cruise around town. 

The Drive

On the highway, the Mickey Thompson Baja ATZ p3 tires are fantastic, especially when compared to the mud-terrain tires. The Suburban drives like a completely different vehicle. While the road noise is about a third of what it was, other noticeable improvements include straight-line stability, cornering, and improved braking. It even feels more stable at speed on the dirt and gravel roads. And while we haven’t found ourselves in the mud yet, Moulton assures us the Baja ATZ p3 is up to the challenge. 

“The Baja ATZp3 is a true all-terrain tire, performing well across all elements. It has the carcass and Siderbiters of a mud tire with an all-terrain tread,” Moulton explained.

While the LS swap transformed our old worn-out Suburban, we would argue that the new tire and wheel combination was just as significant an improvement as the new powerplant. The Squarebody is much more stable and lacks the dreaded tire noise on the highway. The Weld Chasm wheels also set the Suburban off whether it’s sitting still in a parking lot or rolling down the road. Our only problem now is since the tire noise is gone, we can hear nothing but the wind creeping in from the worn-out weather stripping. As they say, “If it’s not one thing, it’s another,” but, we’re heading in the right direction with our family hauler and turning heads while we do it.


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Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
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