Milestar XPDN4 Cascadia: An Overland Trek Through Oregon’s Many Exciting Landscapes

All-Terrain Tires vs. Mud-Terrain Tires

Consumers have a massive amount of options to choose from when it comes to tires. Going beyond the aesthetics of the tires and breaking down the performance, which is better, an all-terrain tire or a mud-terrain tire?

All-terrain (A/T) tires are designed to cover the most amount of terrains including where the vehicle is most commonly at, on pavement. Able to give decent traction on dirt roads and light snow while still coming with mileage warranties, road hazard warranties, smooth rides and general flexibility.

Mud-terrain (M/T) tires were once used nearly exclusively for mud, deep sand or heavy snow. Now, technology has allowed them to expand further and they are widely used in nearly all forms of off-road and many companies have shifted to naming them Maximum-Traction tires.

There has been a gap between the two, however. In recent years, a new option has become more readily available. Hybrid-terrain (or aggressive all-terrain) tires strive to blend A/Ts and M/Ts for a performance minded consumer that still wants the mileage warranty and good road manners of an A/T while getting more traction like an M/T.

All-Terrain Tires

There are many different off-road terrains out there and many of the vehicles that traverse them also spend the majority of their time on the highways and surface streets going about daily life. “Our philosophy with an A/T is something that’s got a broad range of sizes because this is where most of the light-truck market is at.” Explained Martin Castro, Events and Activation Manager for Milestar Tires. “You need to have confidence in things like mileage warranty, 30-day ride guarantee with our Patagonia AT-R, road hazard assurances and having the peace of mind of having the right load rated tires.”

A/Ts will not be amazing performers on extreme or harsh terrains. The tightly spaced lugs and harder compounds work phenomenal on roads, hardpack dirt, and snowy road conditions but they will not grab rocks or sling/float on mud and soft sand the same way M/Ts do.

Good A/Ts come with 40,000+ mile warranties, staggered tread blocks with zig zag sipping to clear debris and water quickly, maintaining better contact with the road. Many of them also carry the Three-Peak Mountain Snowflake symbol which means it was been independently tested and approved for severe snow conditions.

Mud-Terrain/Maximum-Traction Tires

M/Ts are often the gold-standard of off-road performance. Huge lugs with high void tread designs for debris to be cleared, grippy rubber compounds with extra blocks on the sidewalls for airing down. The wide footprint lends itself well to floating on top of mud and sand, and the specifically designed lugs grab and scoop soft terrain or grab tightly to rocks.

M/Ts are, however, durable beasts.

Where M/Ts lack is longevity. The slightly softer compound and extreme use means they just don’t last as long as A/Ts, especially on highways. They tend to be louder due to the high voids trapping air beneath them and often require more frequent rotations to different positions on the vehicle to keep them properly worn.

M/Ts are, however, durable beasts. Able to take a hit far better, tires like the Milestar Patagonia M/T feature a 3-ply sidewall that provides added strength and impact protection. Many M/Ts have smaller portions designed into the bottom of the voids that act as stone ejectors, helping to keep those areas clear and able to grab more terrain. “M/Ts need to have really good traction in extreme terrains.” Said Martin. “Snow wheeling is a huge part of yearly vehicle use for many people, both for fun and necessity so the M/T has to have great floatation and act like a snowshoe on the snow or sand by dispersing the load out.”

Hybrid-Terrain Tires

Hybrid-terrain tires target the best of what A/Ts and M/Ts have to offer. Larger lugs and voids than a standard A/T, stronger sidewalls and extra shoulder blocks while maintaining all-weather road performance and a Three-Peak rating.

“The hybrid-terrain is the evolution of the standard A/T.” Martin explains. “On the Milestar Patagonia X/T, we have combined the strength of the 3-ply side wall and rugged tread blocks on Maximum-Traction tires with the all-weather traction, longevity and smoother ride of All-Terrain tires.”

A good hybrid tire is designed to be aggressive in some areas and tame in others. Expertly designed tread patterns allow for hybrids to gain more traction by stepping up the block and void sizes without severely compromising ride quality, wet traction and mileage expectations. One of the ways Milestar does this is by using a variable pitch tread pattern that alternates the pitch sequence, staggering them in just the right way that produces a quieter ride.

Keep in mind though that hybrid tires are still a hybrid. A middle ground between two ends of a spectrum. They likely will not out perform a M/T on rocks or in mud and most likely wont beat a mild A/T on the street.

The Final Decision

The final decision is up to you. The fact is, most vehicles that are used off-road end up with far many more on-road miles than they do off-road. Every vehicle and every driver are going to have different requirements, even as simple as looks will have an affect on your final choice. As an enthusiast, you’ll need to decide whether you want some performance with lots of on-road benefits, high off-road performance that sacrifices longevity and ride or a blend between the two.

Does Tire Compound Even Matter?

For many people, the only thing they demand from their tires is that they hold air. They don’t know anything about tire construction, the materials used, or attributes of different tread designs. When it comes time to buy, they believe all tires are the same. They choose the cheapest they can find, or insist on the brand they are most familiar with. “Dad always ran brand x tires, so I will run those too. Dad knows what’s best”. These people are notorious for abusing their tires more than the guy down the street who can’t stop doing burnouts.

I’m sure you’ve had to roll down your window in traffic, or mention to someone in a parking lot that their tire is under-inflated, or sometimes even flat. For those people, the exhaustive work of technicians, test drivers, and product development engineers goes pretty much unappreciated. They purchase tires only when they absolutely have to.

On the other end of the spectrum are the enthusiasts who are pushing the limits of their vehicles on a regular basis. If you find one of them with a low tire, it’s because they set it there. They have all kinds of fancy gizmos to air their tires down for maximum footprint, and increase traction, and then to pump them back up again. They bring their own compressors along, and some even have on board air systems with storage tanks, and other accessories. They use that compressed air for obnoxious train horns, to blow dust or dirt out of their rig, or to pressurize a water tank for a trailside shower. Compressed air can really come in handy.

Then there is TPMS; Tire Pressure Monitoring System. From a gauge on the dash a driver can tell nearly exactly how much air pressure they have in each tire (even the spare on the rack) in real time, while they’re driving. It’s much easier to go online and argue whether 10 pounds is the best pressure to run on the rocks, or if 11.5 pounds works better in the sand when you know exactly how much pressure you are running.

The enthusiasts are the ones who delve into the fine details that make up a tire. They know the difference between a bias ply tire, and a radial; how steel belts vary from polyester, nylon or rayon cords. They understand the tire engineer’s lingo of rock ejectors, tread squirm, high void, staggered blocks, siping, etc. Ask the average person on the street what a tire bead is, and they will just look at you puzzled. Anyone who has ever built a beadlock wheel knows what it is, and that the shape, and thickness is critical to getting a good seal on the wheel.

It’s true that many off-road enthusiasts know quite a bit about tires. They might even know what size tire fits which truck, and what the proper wheel offset is in order to clear the fenders without trimming (the number one asked question on the internet). However, not a whole lot of tire buyers think about the rubber compound used. That information doesn’t show up on websites, in brochures, or in the carefully polished sales pitch from the guy at the tire store. Is it important? Why does it matter?

I can tell you from first-hand experience that the rubber compound used is just as important as any other component of a tire. A friend of mine showed up for a trip we took (way back in the 1980’s actually), with a brand new set of tires. We drove out to the mountains on the pavement, ran some trails, and then did a high speed bomb run down some graded fire roads. Once we got back to the pavement for the trip home, we noticed his tires were literally shredded. He had deep slices in the tread blocks and several chunks missing from the tread. He did not know that the tires he bought had a very soft compound. Although they were new, they got torn up from wheel spin on the rocky fire roads. The tread compound was way too soft for the sharp rocks.

Those tires were perfect for mud, sand, or slick rock, but not suited for sharp rocks. Those tires were too soft, but your tires can also be too hard. At the same time that my friend bought those super soft tires, I had military take offs on my Jeep. They had a very aggressive tread design, and were very tough. The compound on those tires was very hard because they were designed to last a long time. They worked great when they could dig into the ground, but on slick, or smooth surfaces they were junk. In cold temperatures they got hard as a rock. They were bias plies so they rode rough as hell.

Those are two examples of tread compound from both extremes; too hard, and too soft. So what’s the perfect tread compound? That depends on what you need. Tire engineers have to weigh a lot of variables when they make this determination. Usually a tire will be configured for the street, part street, and part off-road, or mostly off road. Of course there is also a choice for off road only; The Milestar Patagonia M/T “Black Label” is super soft by design.

It’s for people who want maximum traction above all else. If you compare the Patagonia A/T R, with the Patagonia M/T you will notice right away that they look differently. The tread pattern of each tire is suited for their intended uses. The A/T R is designed more for the street, than the dirt. It will still perform in the dirt, but is rated higher than the M/T in ride comfort, and mileage. Obviously, if you are driving long distances on the pavement to get to the trail, tread wear is important.

The A/T R comes with a 50K tread wear warranty plan. The tread pattern itself helps to increase mileage by having smaller voids, but the tread compound also makes a big difference. The tread compound of the M/T is softer, and when I say softer I mean more flexible. Engineers can measure how soft the rubber is using a gauge that’s called a Durometer; the firmer the rubber, the higher the number. Which tread design and tread compound you choose depends on what your needs, and desires are. If you want better tread life, go with the A/T R. If you spend most of your time in the dirt, go with the M/T. If you still want more, choose the “Black Label” for the ultimate in traction. 

Choosing the Right Tire

Let’s face it, the weather out on the West Coast is awesome. The conditions are more or less predictable, the climate is almost always in the ’70s and sunny, and it’s generally easy to prepare for changes in conditions if, say, you travel up to Tahoe for some skiing.

But for those of us that live virtually anywhere else, Mother Nature chooses to be comparatively more cruel with her distribution of weather conditions. Those of us residing in the Midwest and on the East Coast, as surely you already know, experience seasons; actual changes in temperature and conditions from winter to summer and vice-versa.

Whether you’re an automotive novice or expert, you know that tires are your vehicle’s direct line of contact to the road. Aside from monitoring your vehicle’s tire pressure, treadwear, etc., it’s essential that you also choose the right tire for the season and conditions you’re driving in. The circumferential grooves, tread blocks, lateral grooves, and even whether or not a tire is siped can have an impact on how a vehicle handles and brakes in both the wet and the dry.

Every kind of tire from all-season to all-terrain has specific conditions in which they excel, and this article will help you decide on what kind of tire to use when.

All-Seasons, Not All-Conditions

These are the most common kind of tire found on standard passenger vehicles and SUVs. As their category name suggests, all-seasons can be used in virtually any weather condition. Most vehicles that are equipped with these kinds of tires are used for commuting, not racing, have tread patterns with wider circumferential grooves (for removing water), more basic lateral grooves and tread blocks, have lower speed ratings (S- or T-speed), and longer-lasting rubber compounds.

For vehicles that are more performance-oriented, a performance or ultra-high performance tire isn’t necessarily more appropriate but will compliment your vehicle’s handling and braking abilities in dry conditions, while maintaining wider circumferential grooves to disperse water. These tires have a more intricate, aggressive tread pattern from the outboard to inboard shoulders, higher speed rating (H- or V-speed), and a softer compound, which tends to wear quicker than regular all-seasons.

The Milestar MS932 Sport and MS932 XP+ tires are great examples of this. Both are high-performance tires that feature optimized tread patterns along with wide circumferential ribs and grooves for improved grip and water dispersion. Compared to the MS70, which has both vertical and variable siping for inclement weather, the Sport features lateral siping while the XP+ features 3D, zig-zag siping, which are geared more for a performance grip. The XP+ has the addition of wider shoulder tread blocks for better handling and cornering.

When it comes to colder and wetter conditions though, the performance-oriented all-season tires aren’t as great. Their rubber compounds aren’t made for colder temperatures and the more aggressive tread patterns mentioned limit the vehicle’s ability to not only grip the road but also disperse precipitation when there is water or snow on the road.

…tires are your vehicle’s direct line of contact to the road.

In extreme cases, this could result in hydroplaning, which is essentially when water cannot effectively pass through a tire’s circumferential grooves causing the tire to ultimately lose contact with the road.

Condition Specific Tires: Winter And All-Terrain 

When temperatures drop below 40 degrees or the terrain becomes rough, rocky, or muddy, an all-season tire isn’t going to cut it. Lower temperatures demand tires with specialized, temperature-specific rubber compounds for better grip, while inclement weather conditions and rougher terrain demand specialized tread patterns for better grip. That’s why winter and all-terrain tires exist.

A tire which has met the required performance criteria in snow testing (like the situations mentioned above) will be branded with a three-peak mountain snowflake (3PMS or 3PMSF) symbol on its sidewall. Traditionally, this designation was used only on winter-specific tires, but as of late, more all-seasons have been receiving the certification as well.

Both winter and all-terrain tires have wider, deeper circumferential grooves for maximum water dispersion along with siping. This is where siping, tiny straight or zig-zagged grooves within the tread blocks, really comes in handy. As the sipes come into contact with a surface, they aid the tread blocks with better grip.

In more extreme cases, adding studs to or wrapping them in chains might be necessary. These studs are small pieces of metal that can literally be installed into the tire’s tread and help the tire dig into ice and snow.

When temperatures drop below 40 degrees or the terrain becomes rough, rocky, or muddy, an all-season tire isn’t going to cut it.

Milestar’s Patagonia A/T W is an excellent example of a studdable tire, which has small indents throughout the tread for stud installation and is supplemented with segmented wishbone tread blocks and silica compound for better overall grip.

Similarly, wrapping a tire in specialized tire chains also helps a tire dig to ice and snow, but can be harmful to the pavement when ice or snow isn’t present. Consulting both your car’s user manual as well as with a tire shop is highly recommended if you choose to go for either of these options.

When it comes to all-terrain tires, their inboard and outboard shoulders are typically comprised of lugs—extra large “chunks” of tread—in addition to most standard tire components. The Milestar Patagonia M/T is a great visual example of this. It features high void, lugged tread for maximum traction on rough terrain.

With All That Being Said…

No matter which brand of tire you decide to purchase for your vehicle, it’s essential to choose the right one for it as it could potentially have a huge financial impact. Driving on a winter tire year-round, for example, will yield much quicker tread wear along with poor overall gas mileage. On the flip side, driving on an ultra-high performance tire in inclement weather puts you at a much higher risk of hydroplaning and even crashing.

“The choice is yours, and yours alone. Good luck!”

Bias Ply vs. Radial Ply Tires: What Is the Difference?

When it comes to your standard driving tires, bias ply hasn’t been a term used in decades to describe the latest and greatest tires coming out on high-performance cars. In the racing, trailer, and even motorcycle worlds we still see bias ply but, even then, it’s quickly being displaced by radial tires. So, what is a bias ply and why has it been replaced by radial ply tires?

What’s being referenced when you talk about bias ply and radial ply are how the cords that make up the carcass of the tire are run from bead to bead. You’ll never see it until you wear the tread beyond its rubber layer. The term “bias” and “radial” are describing how the patterns of the ply are done.

A bias ply tire has its plies in a crisscross pattern as they overlap each other. So, one ply will lay in one diagonal (between 30- and 40-degrees from the direction of travel) while the other will lay in the opposite direction and would make an “X” if you were able to see through them. You can have multiple plies in a bias ply tire, too, usually in 4, 6, 8, or even 10 plies.

Most will be 4 plies, though. Bias ply tires also use far more rubber to create both the sidewall and tread as well as being supported by the plies. This was how tires were done from the 1930s all the way into the 1970s, with the last few cars coming with a bias ply in or around 1974.

A bias ply tire is far more flexible, so they can make for great off-road tires and drag radials where sidewall flex is beneficial. They also exhibit better traction at low speeds and in straight-line travel.

[Bias ply] treads wear faster and exhibit more rolling resistance, so you go through more money as you use up the tires and your gas far more often.

Because so much rubber is used, they are far more resistant to cuts and punctures. However, because they use so much rubber and are more flexible, they lose traction in cornering because they tend to roll-over on to the sidewall.

The treads wear faster and exhibit more rolling resistance, so you go through more money as you use up the tires and your gas far more often. This also means you’ll get flat spots if you allow a bias ply tire to sit on the vehicle’s weight for too long. You’ll also feel like your wandering due to cracks, ruts, and bad driving surfaces as these tires tend to follow those deformations.

While the tread isn’t directional, the way you rotate bias ply tires for maintenance is specific to them. You’ll take a left rear tire and move it to the left front, left front to the right rear, right rear to the right front, and right front to the left rear. Well, unless you have five tires (where you can use the spare as a normal driving tire) and then the left front becomes the spare and the spare moves to the right rear.

A radial tire, however, has its plies in a 90-degree pattern from the direction of travel from bead to bead (or radially from the center of the tire and where they get their name from). They have been around longer than most people realize, with tire patents dating back to 1915 by Arthur Savage in San Diego, California (the patents expired in 1949).

In France, Michelin designed, developed, patented, and commercialized a radial design by their researcher, Marius Mignol, in 1946 and Michelin X radial tires were installed as a factory standard tire for the 1948 Citroen 2CV.

…[Radial ply tires] have been around longer than most people realize…

The first factory standard radial tire for the US is credited to the 1970 Lincoln Continental Mark III after the August 1968 issue of “Consumer Reports” showed that they had better tread life, better steering characteristics, and less rolling resistance.

What makes the radial superior to bias ply tires (outside of high-load capacity) is that those radial cords allow better flex. It makes a tire act more like a spring and improve riding comfort even as load capacity rating increases. This also increased tire life as the flexing required was easier than bias ply, which would resist and begin to overheat the tire. Because of its radial pattern and using less rubber, you’re able to run a much wider and flatter tire footprint.

These tires will also have a rigid set of belts to reinforce the tread, usually made of steel, Kevlar, polyester, Twaron, or sometimes even a combination of them. That means that your sidewall and tread function as two independent part of the tire instead of one like a bias ply.

These belts can also be added between plies to meet specific design goals like reinforcing the sidewall for puncture resistance, increasing load capacity, and many other objectives.

Because of that and the expansion of rubber compounds using silica, we’re starting to see more and more applications that use radial tires over bias ply. In racing, many tires are now radial over bias because of the advantages of feel and character of the radial.

Much like the carburetor, the bias ply won’t go away but it will be only around for the niche.

Even drag radials are offering more straight-line grip and sidewall flex needed for powerful launches on the strip with the added benefit of not needing inner tubes.

For off-road, radial tires offer better flex and more grip on the rocks and sand. Trailer tires have even begun to make the switch to radial, even in higher load capacities typically reserved for bias plies. If you’re trying to look period correct, there are even radial tires for you.

The short story is that the areas where bias ply dominated are no longer solely for them. Radials have become an acceptable replacement in those areas. As ply and rubber technology continues to improve, the need for any type of bias ply will be left for those who are just in it for numbers-matching correct restoration. Much like the carburetor, the bias ply won’t go away but it will be only around for the niche.

Is There an Ultra High Performance Tire Right for You?

You build your car and have made it look like something straight off the race track. However, you don’t plan on driving it on the track all that often. Should you really have a set of Ultra-High Performance tires (or commonly known as UHP tires) on something you don’t track?

Someone who builds a cool looking car that’s low and functional doesn’t always end up on the race tracks across the world. There’s nothing wrong with that and people have been doing that since the early days of hot rodding. Even if they do track their cars, many drivers assume they need UHP Summer or “R-compound” tires for their car when, in reality, they don’t need them for daily driving. They quickly realize they are starting to waste a lot of money on those rubber donuts.

This type of UHP tire is typically designed to be used in environments that are warm and dry enough that they provide the right amount of traction to drive fast. The tread itself is very thin, usually no more than 5/32-inch deep with few sipes and grooves.

They quickly realize they are starting to waste a lot of money on those rubber donuts.

This means the ultra-high performance tread pattern is focused on providing maximum grip to a “clean” driving surface and their tread blocks will have very few voids and channels for water evacuation. Their rubber compound will also be softer to provide more mechanical grip at the limit.

This also equates to a tire that can take some time to learn to drive on the limit with. Many times, they don’t make enough noise or even breakaway slowly. When you go over their limits, it characteristically happens fast and without any audible warnings like you get from your typical street tire. It’s why many track day teachers will tell you not to drive on a UHP tire on your first few events until you get used to your car and how to drive by feel rather than sound.

It’s these characteristics that also make a UHP Summer tire wear faster than a standard street tire and doesn’t work in all seasons. If you drive your car where it rains often or you must drive through even light snow, these tires won’t work. They just aren’t designed to evacuate precipitation that hits the ground and you’ll begin to hydroplane.

UHP Summer and even Winter tires aren’t meant for daily, yearlong driving…

While having a softer compound is great for cold climates—where normal street rubber would become harder and not grip—that compound will also wear much, much faster. Ultra-High Performance Summer and even Winter tires aren’t meant for daily, yearlong driving because they wear much faster in warmer weather.

However, that doesn’t mean there isn’t a UHP tire you can’t take advantage of. You should look at the UHP All-Season tire for your daily driving needs. These tires have the tread pattern to allow for water and even snow evacuation so you have grip in the wet. The tread is usually between 8/32- and 11/32-inch deep but their tread siping is also designed to support their neighboring tread blocks using interlocking sipes. This means, as you corner in a high-G load, the tread blocks support each other and prevent them from bending too much during cornering, decreasing heat that leads to tire tread chunking and degradation.

They also have a specific tread compound that works in both warm and cold environments as they contain more silica in the compound. The black color your tires have comes from carbon black. This carbon black also helps determine the softness of the rubber compound, so the more carbon black, the softer the compound is.

…UHP All-Season tires really can let you have your cake and eat it, too.

Tire manufacturers have begun to use silica (also known as silicon dioxide), a type of compound that many try to describe as sand. Silica is only a part of sand, however, as this compound is also found in quartz and even living organisms.

What makes silica amazing, and why it’s being used in UHP tires more often, is that it provides a lower rolling resistance while also improving the grip of rubber tires and results in a more elastic and flexible compound at lower temperatures versus similar tires with more carbon black. According to Rubber World, “The use of silica can result in a reduction in rolling resistance of 20% and can also improve wet skid performance by as much as 15%, substantially improving braking distances at the same time.”

So, UHP All-Season tires really can let you have your cake and eat it, too. However, if you are participating in a track day and have some experience under your belt, you should be using a set of UHP Summer tires then. If you’re just trying to look the part, you can stick with the UHP All-Seasons all year long. That way, you get the benefits of more grip without the headaches of spending money on constantly replacing worn tires and worrying about hydroplaning in the wet.

Going Big: A General Guide to 40-Inch Off-Road Tires

Going off-roading means you need 40-inch tires, right? Well, it depends. There are some things you need to take into consideration before going oversized.

First, we must confess that this is a bit of a generalization. What we’ll be discussing here might not be exactly what your truck or SUV needs to make that jump to a 40-inch tire. For example, your rig might come with axles strong enough to turn a 40-inch tires without breaking the splines or itself in half. You might be able to remove your fenders on your Jeep but the guy in the F150 can’t.

If you’re just a mall crawler, you might be fine with mostly stock stuff, but if you do go off-road, you’ll need upgrades. So, this will be a guide of things to take into consideration before plunking down cash on those big tires. We won’t touch on anything specific to any single vehicle.

Let’s start with the thing everyone points out as the first thing to change or at least modify: your axles. First, why? Why do you need to consider your axle when changing to larger diameter tires? Much of it has to do with the diameter and additional weight of the tires. Yes, you need to re-gear (and recalibrate your speedometer) to overcome the increased overall gear ratio. A 33-inch tire will have a rollout of 103.7-inches and will rotate 630 times per mile.

A 40-inch tire, on the other hand, will have a rollout of 125.7-inches and will rotate 517 times per mile and means you are going further on each rotation. By changing to a taller tire, you’ve essentially increased your overall gear ratio and will be showing a slower speed than what you’re actually doing. So, if you were doing 65-MPH with a 33×12.50, you’ll be doing nearly 80-MPH with a 40×13.50 while still showing 65-MPH.

…if you’re going with big tires, most likely plan on going with bigger axles at the same time.

This means you would not only have to recalibrate your speedometer but also need to re-gear to keep the engine RPMs close to the same for the corrected speed. Fortunately, there are many online calculators to help you determine what gear you need for the tire size increase as well as handheld tuners that allow you to recalibrate your speedometer for your tire size and gearing.

That won’t be the only problems with your axles, though. Because of the increased weight, you’ve also increased the rotational mass and resistance to rotation. This means you’ll need more torque and you’ll do that by adding power or decreasing your gear ratio or both. This increases stress on the axles and usually leads to failure at the splines and axle shafts on straight axles and, additionally, failure of U-joints or constant velocity joints on independent axles. So, if you’re going with big 40-inch tires, most likely plan on going with bigger axles at the same time.

You’ll probably want to invest in new driveshafts, as those will be the next weakest links when it comes to transferring torque to your axles. Most truck and SUV transmissions and transfer cases can operate fine with big tires, but you’ll want to inspect them more often or consider a swap out for heavier-duty versions from the aftermarket. You won’t necessarily need an Atlas or even an NP205, but definitely look for upgrades for your chain-driven New Process transfer case that will allow it to handle more torque. However, if you have a regular NP241, get something better or at least an NP241HD.

You’ll need a lift, even if you already have a 2- or even 3-inch lift you’ll need to go a bit higher to clear the tires. This is where an IFS suspension starts to lose its advantages as you raise the truck higher, it will continue to ruin the steering and feel of the truck or SUV. You’ll also wear parts out much quicker because of the stresses and the increased load of the lift as well as the tires.

…it’s probably best for only hardcore off-road rigs and showboaters.

You’re looking at a custom suspension regardless if you stay with your IFS or swap the front to a solid axle. For the rear with leaf springs, you’ll be able to find re-arched springs for a decent lift without needing to resort to a huge block for sprung-over axles (where leaf sits on top of the axle). For sprung-under, you’ll have to convert it to sprung-over or you’ll have arches so large it will be pointless.

If you don’t lift, the body will need extensive modification for a 40-inch tire to work. If you don’t want to cut sheet metal, your only other option will be to replace it with fiberglass parts made for prerunners and desert trucks. If you cut metal, most states will require you to have something to cover the tires and have clearance lights on fender extensions to remain legal. Easy to do on a Jeep, not so easy to accomplish on anything with a regular body.

You’ll also have to make sure the wheels you use to give you the right backspacing (offset) to clear those very wide tires. The rear can typically be more aggressive than the front and can get away with higher backspacing (lower offset). The fronts, however, need to be spaced so that you can turn properly and not rub the frame or suspension components. Again, in many states, there are also legal issues with tires rubbing the body and chassis.

Running 40-inch tires isn’t easy, in fact, it’s probably best for only hardcore off-road rigs and showboaters. It’s not impossible to run that big of a tire, but there are many, many things you need to consider before doing it. This is just a short list as there are explicit things you need to do to specific vehicles to run tires this big. The best piece of advice we can give you is to research. Look for who’s done it with a vehicle like yours and see the trials and tribulations they had to go through to make it work. Then, decide if you’re willing to do the same.

If not, there’s nothing wrong with running 35s on your truck, SUV or Jeep and they are plenty capable. Just ask the guys who race in the Ultra4 Every Man Challenge.

38 Inch Special:
A Guide to 38 Inch Tires

Go into any current forum or social media group for Jeeps and 4x4s and you will find the most frequently asked question is “How big of a tire can I fit on my *insert 4×4 here*?” The question is posed so frequently that the query is “stickied” to the top of the forum page with countless replies. “You can fit 35 inch tires if you have…” “37 inch tireswork, but only if you’ve done…” “You need tons in order to run 40 inch tires…” (“Tons” is shorthand for 1-ton axles sourced from a pickup). They’ve all been asked.

These seemingly universal 4×4 questions have been answered in their entirety, which we won’t get into here. The Jeep community has seen the 37×12.50R17 become the ubiquitous size on any new Jeep. Go back just over a decade and 37s were the extreme size tire to have and only a handful of brands to choose from. 33s and 35s were BIG, but 37s meant you were serious! So how did this desire for ever-larger tires come to be so common and why is there such a jump in size going from 37 inch tires to 40 inch tires with no choice in between?

In today’s tire world, nearly every tire manufacturer has an All-Terrain (A/T) and a Mud-Terrain (M/T) in a 33, 35, or 37 inch tire that fits on a 17 inch rim. These sizes have become a standard upgrade for several reasons. First is 4×4 vehicles are bigger than ever before with auto manufacturers adding extra space, seats, and cargo capacity. Second, with the added space and creature comforts comes the weight.

33s and 35s were BIG, but 37s meant you were serious!

Everything gets bigger from the drivetrain, axles, brakes, steering to handle the extra weight and still be a capable vehicle. This transition to more capacity and capability was lead by growing popularity in outdoor activities amongst families. With the vehicles and their components getting bigger and adding capability, enthusiasts took to modifying them with greater earnest and in greater numbers. One of the easiest ways to add capability is by gaining clearance through a larger tire size.

It can be argued that this rapid expansion in tire sizes was brought about by the advent of a single vehicle: the 2007 Jeep Wrangler Unlimited (JK). It dropped the iconic Inline 6-Cylinder for a V-6 that was better suited to a minivan than a 4×4. The improved approach and departure angles showed enthusiasts that Jeep engineers were focused on making a capable vehicle.

But the one change that was seen as heresy initially and is now beloved: 4 full doors. Jeep aficionados scorned the longer Wrangler, thinking it more of a minivan than a true Jeep. But over time, the extra wheelbase lent itself to improved off-road capability, with the right modifications.

Chief among them: Larger tires. Tires are the only thing that connects the vehicle to the ground. They are the easiest and quickest way to gain ground clearance, improve approach and departure angles, and provide that oh-so-desirable “tough” aesthetic that many enthusiasts are after. But there is a canyon in terms of budgets between running a 40 inch tire and the ubiquitous 37 inch tire.

But the one change that was seen as heresy initially and is now beloved: 4 full doors.

40s are an average of 40-60% more expensive than their 37 inch tire counterparts, and a lot of expensive changes have to be made to the vehicle in order to reliably run a 40 INCH tire as well. So what does an owner do when they want more than their 37s, but can’t afford or justify the required upgrades for 40s? Enter the Milestar Patagonia 38 inch.

While the 38×13.50R17 is only one inch taller than its smaller sibling—the 37 inch, it pays off in ways that become greater than one would initially think. It poses less strain on the hard parts that turn and drive the tires when compared to 40 inch tires. The 38 inch tire size clears factory brackets and bumpers and keeps any sort of body modification to a minimum.

Wheel offset, suspension bump stops, steering, and fenders all can stay the same if the vehicle has been properly kitted for 37’s. Where 37’s provide a better “stance”, the 38 inch tire make the vehicle look like it has 40s. All of this is gained with a reasonable bump in price on just the tires. Not only is the 38 inch Patagonia M/T taller, but it’s a bit wider at 13.50 inch giving the wheeler that much more of a footprint.

The tires’ C-Load Range is also a nod to the recreational wheelers as it is commonly thought that having some sidewall give, while still being 3-ply, will allow the tire to “grab traction” or “bite” when aired down. This is further supported when one takes into consideration that tire manufacturers often modify the construction material of the plys depending upon the load the tire is expected to bear and how much air pressure it is rated for.

…the added capability of a 40-inch tire, without the 40-inch wallet.

Strength is upheld with the Patagonia, while being a more focused 4×4 product. At 82 pounds, the 38 inch Patagonia M/T’s optimized construction is shown as it is the same lighter weight as many of it’s 37 inch competitors. This is important because added unsprung weight negatively affects suspension performance and ride quality.

In addition, extra weight also brings down fuel economy and increases wear and tear on the drivetrain and steering components. The 38 inch Patagonia M/T is constructed to balance strength, size, and weight; all major factors when enthusiasts start their 4×4 project.

The 38 inch Milestar Patagonia M/T is the choice when one wants the added capability of a 40-inch tire, without the 40-inch wallet. It is tailor-made for the recreation wheeler with its strong, yet pliable sidewall, all-important 17″ wheel construction, and true 38 inch tire sizing. Your next question is simply where will you buy your set?

All Surfaces, All Traction

What Is an All-Terrain Tire?

Want a tire that gives you traction no matter where you are? Well, that doesn’t exist but there is a tire that gives you great all-around traction with some compromises. That tire is the All-Terrain – or AT – tire, which used to be a single category until recently. We’ll go over the most common versions of the AT in this story.

Unlike the MT tire, the All-Terrain is a compromise between on-road comfort and off-road capability. AT tires don’t generally excel in either area but work at their best in either. They feature smaller tread blocks for the best on-road noise and wet surface grip, but the blocks are still large and aggressive enough to be used in dirt and light rock off-road conditions. However, there has been a change in how an AT tire is designed and now there are two types of tire designs within the AT tire class. Each type of AT gets closer to the MT design.

The classic AT, like the Patagonia A/T W, is designed with more on-road performance than off. Some will call this an AP (All-Purpose) or Trail type All-Terrain but there is a specific All-Purpose tire category. So, calling an AT an AP tire is technically wrong. This is mostly because it’s capable of going off-road, but its smaller tread blocks and grooves allow mud to “stick” to the tire more. This reduces traction in that condition, but the smaller tread and harder tread compound mean that it won’t do well in rock crawling conditions.

The tread also doesn’t travel down into the sidewall and it features fewer belts than the MT tire. The sidewall ply and bead design will also only allow for normal tire pressures of 30-PSI and above. When people think of “truck tires,” like what you’d see on mid- and full-size pickup trucks and SUVs, this tire design is what they will picture. It’s perfect for trucks and SUVs that don’t see much off-road action, but if it does, it’s only going to be down a dirt road.

The next step in the AT ladder is the AT-X or AT-R tire. This type features larger blocks than the standard AT and you can see this in the Patagonia A/T R. The tread blocks are much more aggressive and somewhat larger, and the sidewall of an AT-X has some tread, but not to the extent of a full MT tire. It also features more siping than an MT, but not as much as the AT. Again, the siping is there to reduce squirm and improve wet road surface traction by giving water an evacuation path. The AT-R or AT-X type All-Terrain tire is perfect for vehicles that see more off-road surfaces but still travel mainly on surface streets. It’s probably not going to work well as a rock crawler or dune tire, but you’ll be able to get to your favorite off-road and camping spots with no issues.

What both types of AT tires feature is reduced road noise. This is an integral feature of any tire that has smaller tread blocks and more grooves and sipes. When the tread rotates onto the road surface, it compresses the air. That loads up air like a spring and when it escapes, it does so at Mach speeds from the energy it gains from being compressed. If the air has a path or pocket to escape to, it reduces that compression and potential energy. That slows down the air’s speed and you no longer hear the howl as you do of an MT tire.

The AT tire is the best compromise of on-road manners and off-road capability. You’re not going to be crawling up Jackhammer with either AT tire, but you’ll produce less noise than the MT tire. You’ll be able to get to a spot where you can watch your favorite Ultra4 racer and drive home with more wet surface traction than the mud tire. If you want more off-road traction, then the AT-R or AT-X will be a better choice. You’ll get a more aggressive look than the AT and better performance off the asphalt, too. However, if you need absolute off-road traction, then you’ll have to consider something more aggressive.

Max Traction

What Is a Mud Terrain Tire?

When you think of the ultimate off-road machine, you probably imagine it having Mud Terrain – or MT – tires. What makes an MT such a specific tire? We’ll answer that today.

A Mud Terrain tire, like the Milestar Patagonia M/T, is designed for extreme off-road terrain. Despite its name, the MT is used in more than just muddy conditions. The focus of this tire type is debris ejection, be it mud or stones. Clearing out the grooves naturally with tire rotation allows the tread block leading edge to grab the next portion of the surface and “claw” through it. So, the grooves act sort of like a scoop. Otherwise, the grooves fill up and the tire loses traction.

However, an innovation made by Mickey Thompson in the 1960s and featured on nearly every MT tire since is the sidewall tread. Allowing the tread to continue down the sidewall of the tire gives the MT another area for traction in rocky and silty sand conditions. When aired down, the MT’s sidewall tread also helps to increase the tread width as the tires flatten out under vehicle weight.

Because it’s made to be aired down, the MT tires carcass is also designed much differently than a regular street tire like the Milestar Grantland. It typically features more belts to deal with the additional stress airing down creates on the sidewalls. Those belts are also designed to flex despite adding more of them. The beads are also designed to hold on to the rim at lower pressures, usually down to about 20-PSI before needing beadlocks. However, that’s not true for all MT tires. Some can go lower, some can’t go that low without a beadlock. Again, it’s up to the design so always follow the recommendations and warnings from your tire.

One of the biggest down falls of the MT tire is noise. Large tread blocks compress air into the ground, putting it under extreme pressure at the microscopic level. When the tread rotates, that highly compressed air shoots out at Mach speeds and creates the howling noise that’s typical of a very aggressive and blocky tread pattern. The other disadvantage to those large tread blocks is squirm, traction in wet road conditions, and rubber compound life.

Squirm is the movement of the tread on the road surface as the tire drives down the road. Because of its large size, the large lugs will squirm more and create heat. That heat travels through the lugs to spots where it can’t cool off and creates hot spots. The combination of squirm and hot spots creates weaknesses in the lug and can cause chunking. Squirm is typically worse on the steering axle than the drive axle, but the drive axle can still see some squirm as you accelerate on changing road conditions.

Despite its great off-road traction, wet asphalt or concrete surfaces will be its weakest points. Those large tread blocks with no grooves have a reduced amount of water removal. While the water can travel around the blocks, the blocks contacting the surface is trying to squish down water that’s between it and the road surface. Since the water is a nearly incompressible fluid, the tread rides above the surface. This is hydroplaning, which reduces traction to zero because the rubber can no longer form with the road, which is what creates grip.

A tire’s rubber compound, which arbitrarily describes the softness or hardness of rubber in tires, can also increase grip if its softer. Many MT tires are softer than their road cousins due to the requirement of traction in sand and rocks. That also means that a MT tire won’t always last as long as regular road tires. Not always, but a majority will not.

However, modern MT tires like the Patagonia M/T are designed with mixed surfaces in mind. So, while the tread blocks are still larger than a standard road tire, they feature additional grooves and purpose made sipes. The sipes allow the tread to move in smaller sizes, reducing the squirm when compared to a fully solid tread lug. The combination of grooves and sipes also helps in removing water so the tread can grip on wet asphalt and concrete roads. They also help reduce road noise by giving air an escape route before being compressed into the road.

Do you need a MT tire? Maybe. Maybe not. The only way to answer that is to ask yourself this question. “Where am I using my vehicle the most?” If you’re mostly running on surface streets with little to no off-road use, then you don’t need a MT tire. If you’re response is the opposite, how often are you on those off-road conditions and can you deal with more road noise produced by those tires? If you just want a tire that looks cool and don’t care about noise and wet surface traction, you can’t beat the aggressive looks of the MT but there still might be a tire right for you that isn’t a MT.