If you’re renting construction machinery, you’ll be faced with the choice of tracks vs. wheeled equipment. Don’t be alarmed. The debate over tires vs. tracks is ongoing. Industry experts agree that there’s no definite line deciding which propulsion system works best. All have opinions about where and when to use tires vs. tracks.
Your decision on whether tracks or tire equipment is best for you is not simple. It depends on when and where you’ll be using the equipment. It depends on job specifics—what you’re using the machine for. It also depends on gaining traction in difficult ground conditions or making the least amount of disturbance to your work surfaces.
While there’s no such thing as a universal choice, it often comes down to a matter of stability vs. mobility. We’ll look at the advantages of tracked equipment as well as tires but first, let’s look at the difference.
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Tracks vs. Tires: What’s the Difference?
You’ll see both tires and tracks on all sorts of construction equipment. Small machines like skid steer loaders (SSL) use rubber tires to maneuver about job sites quickly. Their counterparts, compact track loaders (CTL) are propelled by slower-moving linked tracks. Some CTLs have steel tracks. Some use rubber tracks. A few small loaders even use a system where rubber tracks are fitted over inflatable tires to give the machine extra traction in changing ground conditions.
Moving up to larger construction machinery, the tires vs. tracks dilemma continues. You’ll see large loaders operating on tires, and you’ll see a few on tracks. The same goes for excavators. Tracks are the predominant propulsion choice on excavators, but there’s no shortage of diggers on wheels.
What’s the difference? Why are some on wheels and some on crawlers? It’s all about traction and protection for the particular ground and site they’re operating on. These equipment operators pay attention to what they’re using their machines for. That determines why they choose tracks or tires. Here’s how traction and protection apply in the differences and features between the two.
Traction for Construction Equipment
The main difference between tires and tracks is how they distribute weight. Tires have small areas that contact the ground during their revolutions. The machine’s entire weight, whether loaded or unloaded, has to be continuously transferred to the ground. This concept is called “point loading” where weight is distributed evenly through four sharp points in four-wheeled machines.
Weight transfer is rated in pounds per square inch (PSI). The machine’s complete weight has to travel through each tire’s ground contact point and spread as evenly as possible. Therefore, narrow tires that sit on shallow ground have less contact area, and they distribute higher PSIs. Conversely, wider tires that cover bigger ground areas spread the loads further, and their PSI impact is less.
Tracked machines have a much greater ground contact area than wheeled equipment. The length and width of tracks cover a larger area than wheels do. This significantly reduces load transfer and creates much lighter PSI sharing than wheels can ever accomplish. Tracks actually work to float the machine over the ground rather than cut into it.
On ground conditions that are hard and flat, weight distribution is not a large concern. Solid ground can take enormous point loads without disturbing and causing support failure for a machine. It’s when ground conditions soften that tracks offer a huge stability advantage. The softer and slipperier the ground, the more traction advantage you’ll have with tracked equipment.
Traction is a critically important concept in understanding tracks vs. tires advantages. There’s a scientific principle called the “coefficient of traction” that determines how much traction a tire or track can get. The coefficient is the relationship between the available pull (ground conditions) and the weight acting on the drive unit (track or tire). The traction coefficient formula is “pull = (coefficient of traction) x (weight on drive units)” and it’s measured in a decimal rating with 0.1 being almost no traction and 1.0 being a really good grip.
An interesting study produced a telling graph on how steel tracks and rubber tires compared with their traction coefficient depending on ground conditions. Here’s how tires and tracks stood against each other on various surfaces.
Traction Coefficient Comparison; Tracks vs. Tires
This study rated tracks and tires side by side. You’d think that tracks would provide better traction every time, but the study says otherwise. Surprisingly, tires outperformed tracks in a few areas while tracks clearly won out in others. In some conditions though, neither propulsion method was strong. Let’s look at the traction coefficient results:
It’s apparent from this study that tracks are superior in wet and loose surface conditions; they even perform a bit better on ice and snow. On really hard surfaces like concrete and asphalt, however, tires appear to have the better traction due to rubber’s grip compared to the limited friction offered by steel tracks.
The other main difference that influences your choice between renting track machinery and rubber-tired equipment is the protection you need for both tracks and tires as well as the ground you’re operating on.
Tire and Track Surface Protection
Protecting both your working surface and your machine’s drive parts are strong influencers on whether you’ll choose a track or tire-equipped machine. As the study pointed out, there’s a big difference between the traction abilities of each ride system, due to the weight and traction bearing qualities of the ground conditions.
Some ground is much more delicate than others, not in composition but value. If you’re working in urban areas with already improved surfaces, you may be better off with rubber tired equipment. Think of the damage you can do to road surfaces, sidewalks and parking lots; the same goes for landscaped areas.
If you’re on pioneering ground, like forest clearing, or are doing heavy excavating for building construction, you’ll likely choose tracked equipment. Tracks are notorious for exchanging weight support and traction for chewing up the ground. That attribute doesn’t matter when the ground will later undergo repair works, but it’s a big deal around existing civic projects.
Protection extends to the machine itself. Rubber tires are easily worn or punctured when operated on abrasive surfaces like crushed rock and demolition debris. Tracks, on the other hand, stand up well to rough and loose surfaces. However, tracks suffer premature wear when shifting about on solid ground that restricts slippage.
Site conditions enormously influence your decision to rent a track machine over a wheeled piece of equipment. Traction and protection are part of overall performance. There are other factors to consider before weighing the advantages of tracks vs. tires, which is where stability and mobility factors come in.
Mobility vs. Stability Factors
Rubber tired machines have a big advantage over track machines when it comes to speed. Most pieces of track machinery can only crawl along at a few miles per hour, but those on tires zip along faster than a person can run. Speed is important when you need to make multiple trips over long distances, which is why you’ll see rubber-tired loaders in gravel pits and skid steers with wheels at landscape jobs.
Construction machines with tracks are slower by intentional design. That’s not to say that track machines can’t move fast like army tanks or personnel carriers. It’s that construction sites usually don’t require traveling speed from equipment unless there’s a specialized need for it. Then most machines can be equipped with wheels to fulfill it.
Mobility is more than just speed. Mobility includes the ability to maneuver in tight places. This often puts rubber-tired machines at a disadvantage as they need room to turn about. Track machines are designed to turn within their own footprint or radius. They can swing in a circle without forward or backward motion by braking one track and accelerating the other. Machines with tracks can also shuffle side to side which is impossible for those mounted on wheels.
Machine stability is another factor to include in your decision when choosing tracks or tires. Tracked machines have a wider footprint with considerably more ground contact than wheeled equipment. Because of the heavy undercarriage built into track machines, they have a lower center of gravity than higher and more unstable rubber-tired machines.
Stability is crucial when working on unstable ground and slopes. The massive ground contact given by tracks creates significant friction that stabilizes machinery when forces of gravity pull them sideways and downward. Wheeled machines don’t have this quality — they easily slide and slip on slopes and sink into loose soil and wet ground.
Traction, protection, mobility and stability are the main differences between tracked machines and wheeled equipment. All have benefits you should equally consider in your rental decision, but there are other advantages and disadvantages to both types. Let’s have a detailed look at the advantages of tracked equipment. Then we’ll compare the advantages wheels will give you.
Tracked Equipment Benefits
Tracked equipment clearly has benefits for several reasons. These reasons include mobility in certain applications, traction and stability as well as protection of the drives and running components. There are other important points to take into account when choosing to rent machinery propelled on tracks.
Here are some considerations:
- Seasonal concerns are important. Tracked equipment can get into job sites earlier in the spring in areas that present thawing and high-water challenges. Tracks will float across the wet and soggy ground while wheels simply can’t support a machine’s weight and carrying load. That means a longer operating window and more potential for profit.
- Less Downtime is another benefit of track machines. This estimate includes downtime from seasonal restrictions as well as breakdowns and repairs. Tracks are built to be tough where tires have their limitations. It’s easy to puncture and deflate tires in rough conditions. Sideways jolts can cause rims to pop their tires. When this happens, tires can get severed and shredded, which doesn’t happen to tracks.
- Smoother rides are experienced with track machines. Their long bases and massive footprints let energy absorb better than wheeled equipment. Operators benefit from ride comfort as they’re less likely to be jostled by bumps, dips and hollows.
- Flexibility is another benefit you can get with tracks. Tracked machines can be operated in virtually every working condition, some of which would disqualify rubber-tired machines. From swamps to bare lots, a tracked machine can travel. When working on sensitive sites like improved properties, you can equip your machine with street-friendly rubber cleats or entire tracks.
- Consistency is still another advantage to renting tracked equipment. Wheeled machines experience “power hop”, which happens when one or more tires lose traction and break free. This problem interrupts work and can also be dangerous in losing control. Power hop doesn’t happen in tracked machines. They remain consistent in delivering power to the earth and remain in control.
Common tracked equipment include:
Wheeled Equipment Benefits
Every piece of construction equipment has its place and purpose. Tracked machines certainly have a wide application and are immensely popular with operators who know where tracks are best suited. Experienced equipment operators know track limitations.
They also know these advantages from rubber-tired machines:
- Cost effectiveness is hard to argue when comparing tracks vs. tires. Capital costs of purchasing and renting wheeled machinery are lower than acquiring equivalent equipment with tracks, due to the expensive undercarriage that track machinery requires. Wheeled machines only have tires, hubs and brakes to absorb, not the mass of support that track equipment needs.
- Maintenance is less with rubber-tired equipment. There are fewer moving parts, which translates to less wear and tear, which means there’s less to repair. Maintenance on drive systems that rotate rather than slide is faster and cheaper. That discount equates to less operating overhead, which reflects on the bottom line.
- Transportation is simpler with machinery on wheels. Rubber-tired equipment can often be driven from site to site rather than be transported on a trailer pulled by an additional truck. This factor saves money and the time required to call in a truck and trailer then load, ship and unload it.
- Lifecycles are longer with wheeled equipment. Machinery built on tracks has fewer hours of lifecycle in the drive system compared to ones mounted on tires. Hubs, brakes and rubber tires last longer, which extends the machinery’s lifecycle. Repairs and replacements are required less often with tire propulsion.
- Versatility is another factor to take in when looking at rubber-tired equipment. Most wheeled machines are versatile as they can be fitted with a variety of attachments. This attribute makes them useful for a range of applications from digging and trenching to material spreading and snow plowing. You can even equip wheeled machines with slip over tracks, converting them to versatile track machines where the situation is right.
Common wheeled equipment include:
Which Type of Equipment is Right for Me?
We’ve looked at the benefits of tracks vs. tires as the importance of applying the principles of stability, mobility, traction and protection towards making your decision on which type of equipment is right for you. Again, it comes down to your own unique needs, which depend on different circumstances.
It depends on your particular job requirements and workplace location. It also depends to some degree on your operator proficiency and time allotment. It helps to think of exactly how you’re going to use your rented equipment. To help your envisioning process, here are a few scenarios where track and tire machines excel.
1. Spring Landscaping
You’re doing an early spring landscape job and need to work organic material into rough grades. The ground is wet and soggy and there’s no let-up in sight for dry weather, but the work has to be completed in time for spring lawn seeding. Your best choice in equipment would be a compact track loader or CTL. It’s wide weight distribution from the tracks will let it float over loose material, while a wheeled machine would sink and create ruts.
2. Foundation Backfilling
The task is backfilling a newly poured foundation. You have coarse, dry and free-draining material but it can only be placed on the street by a dump truck. This situation requires you to make many trips carrying buckets of gravel from the pavement, over the sidewalk and then jump the new concrete walls for placement. No doubt you’d be best off using a fast and forgiving machine like a rubber-tired skid steer loader (SSL).
The job entails trenching to repair and replace clogged perimeter drains along the foundation of an old house in an established neighborhood. You want to create minimal collateral damage and there’s limited room for maneuvering. Selecting a mini-excavator on rubber tracks would be the wise choice. It will creep along the foundation and turn within its own radius. Damage to the lawn and hardscapes will be minimal.
4. Lot Clearing
This is a bigger contract. You need to clear a sloping lot of trees and brush then dig a hole for a new house foundation. This job requires a larger excavator with tracks. It will handle anything you can throw at it, be stable on the slope and there’s no concern for damaging vulnerable tires from sharp sticks and rocks. Select the excavator size based on the estimated amount of material to be moved.
5. Ditch Digging
We’re back to wheels here with a ditching job along a busy highway. You have a solid, flat surface to work from but it’s public pavement that needs to be respected. Choosing an excavator with rubber tires is the logical choice. It’s easily rolled along and causes no damage where a metal-tracked excavator would chew up the asphalt.
6. Gravel Pits
A perfect example of heavy equipment where tires are the only solution is when loaders operate in gravel pits. Big front-end loaders handle multiple yards of material at a time. They need speed that tires allow for keeping trucks rotating and reduce pit time. The level surfaces in pits are suitable to high gravity centers and the predictable footing gives good tire traction. Pits are also low risk for tire punctures. This situation makes a track machine impracticable.
Let MacAllister Rentals Help You Choose: Tracks vs. Tires
These six scenarios are only a sample of hundreds of potential situations where tracks and tires are used. Each situation is a bit different but all take into account what traction is needed, how stable the ground is, the mobility requirements and what level of propulsion protection is needed. This combination narrows down your choice and sends you in either the tire or the track direction.
MacAllister Rentals can help you choose. We’re your go-to choice in sourcing the right rental equipment for your job. Since 1999, our professional staff has helped customers decide if they need construction machinery equipped with tracks or wheels. We’re Caterpillar® dealers who supply quality Cat® rental equipment to locations in Indiana & Michigan.
MacAllister Rentals takes pride in Cat machinery. Whether it’s wheeled equipment or tracks you need, MacAllister Rentals is here to give you great advice and service regarding our full Cat line. Contact MacAllister Rentals today for more information on choosing tracks or wheels for your next project.