To create the dozer, machinists in the early 20th century began to affix a blade to the front of early tracked machines, combining the traction of the heavy engine units and the brute force of the blade. This combination was the hallmark configuration of a bulldozer for many years. In the 1960s-70s, however, wheeled dozers began to be developed and today are utilized in situations where mobility and pavement protection are factors.
In keeping with the ongoing trend to incorporate compact equipment into a contractor’s inventory of machines, push blades are being attached to smaller pieces of equipment such as skid steers. One manufacturer has come up with a track loader-dozer combination that has been engineered with genuine dozing capability. So, the evolution continues.
Buyers of dozers mostly are pros and essentially know their needs. Still, deciding between a crawler dozer or wheeled version and the various renditions of each requires a buyer to establish some base lines of knowledge. Some things to consider:
1) In what ground conditions will the dozer be operated?
If the job will be pushing around less than a full blade of dirt — say, a 40 percent blade load — you really don’t need the gripping power and weight of a tracked dozer. A wheeled machine can do the job with greater speed and maneuverability. Planning to gouge out a hillside? A crawler dozer digs deeper and pushes more easily and would be the best choice. Cleaning up a swampy site? A crawler with a longer undercarriage and wider — three feet wide or so — tracks will do the work without becoming mired. Where ground pressure is important, a crawler dozer with wide tracks is king.
2) What will be the most common application?
Not every utilization of a dozer can be anticipated, but identifying expected general usage goes a long way to picking the right machine. Can you get by with a 100-hp midsize dozer or do you need a 350-hp model? Is 6 mph fast enough in moving around a site or will 10 mph be more efficient? Do you need 10 tons of push power or 100 tons? If you need to rip up earth before pushing it around, will a single ripper do the job or do you need a triple shank? Disappointment is a certainty if you fail to plan and end up with a dozer too small, too slow, or too light to do the work.
3) What type of blade will be best for your application?
Without a blade, dozers are just good for packing soil, and are used for such. But a blade moves dirt and having the right blade means the dirt will be moved most efficiently. The standard S (for straight) blade is a rectangular piece of steel slightly cupped to enhance slicing. A U (universal) blade is slightly bowed to contain material and has a spill plate on each end for further containment. Other blade types include straight and universal combination blades and angle blades that can be tilted and pivoted for sloping and ditching. Blades commonly vary in width from eight ft. to 16 ft., sometimes wider.
4) How much blade automation do you need?
Everything comes back to what you will be doing with a dozer. If you are moving dirt to produce a rough approximation of level, your eye is fully capable of directing your hands to control the raising and lowering of the blade. But if exactness is required — leveling a site for a concrete pad or defining the grade of a new roadbed — than a dozer with GPS or laser blade positioning is a necessity. It can finish a site in fewer passes and thereby dramatically increase productivity. Even smaller 75 hp dozers can be factory configured for grade control. Such a system can raise the cost of a dozer about 5 percent.
5) Can you shop around or are you wedded to one brand?
In the lexicon of construction work, sometimes people will slip and use “Cat” to refer to all dozers. Such is the pervasive branding of Caterpillar. However, there are numerous manufacturers of excellent dozers. If you are wedded to one of them for some reason, then a dealer of that brand is where you should be shopping. If you have less loyalty to a particular brand, do your due diligence online and in dealer lots, comparing prices, features, warranties and reputations. You might surprise yourself in the end and select a brand you hadn’t considered in the beginning.
6) If price is the principal concern, consider buying at auction.
Dozers have been around for nearly a hundred years, so there are many, many used machines to be considered. Auctions are one buying venue to consider. The reputation of auction houses continues to be burnished as best practices take root. Inspection reports can be thoroughly scrutinized before auction day, as can a piece of equipment itself. Often the condition of a dozer is certified by an auction house, meaning less risk for the buyer. The internet can safely bring into your office used machinery auctions from around the country and world. The rest is up to you.
If conserving working capital is crucial, foregoing ownership of a dozer can make sense. Plus, transporting a machine is shared by the rental company and you don’t have to worry about a covered place to park the machine between jobs. Here are rent/lease considerations:
1) How many weeks or months will you need the dozer?
How does the rental of a dozer fit into your business plan? You need it for a week to finish a job, two months to knock down woods, clear acreage and prepare a job site for a 300-home development, or do you need it for a year of road-building? You’ll want to find leasing terms that best serve you over the course of your lease. If you sign a contract unwisely, you may get the job done fine but at needlessly extra cost.
2) Don’t lose sight of the intended use of the machine.
Sometimes a leasing offer will be made that’s very enticing — even though it’s for a machine that’s less than fully suitable for your work. The leasing rate on a 130-hp Caterpillar D6 seemed just too good a deal to pass up, you say, even though you knew you needed the versatility of a 240 hp wheeled model? What you’re feeling is regret. So, is the blade the right size? Engine powerful enough? Know what you need and get it.
3) Be aware of a leasing company’s record of service.
National and independent rental houses and OEM dealerships stay in business because they provide needed equipment at acceptable rates. The differentiator among the businesses often is the service they offer in support of the equipment. How well do you know management — will they be there in an emergency? What is the service reputation of this dealer or that one? Will they show up after a breakdown? Rates aren’t everything.
As with any equipment investment, research a dozer line before inspecting a particular second-hand machine. Have some idea of where wear-and-tear shows up on a dozer. Be able to recognize the telltale signs of misuse. Suggestions:
1) If you are not a dozer authority, invite one along for the inspection.
Familiarity with a crawler dozer is crucial, so have someone with you who knows its operation. Unusual leakage on the inside of tracks is not a good sign, but you have to know what is usual. Are pins or bushings in the undercarriage greatly scored? It could mean the tracks were run too tight, another red flag. Someone who has operated a tracked dozer knows when a used one sounds, runs, and looks OK. Lean on his expertise.
2) Has it been abused in its operation?
Dings are to be expected in construction machinery, but punctures are something else. Welded places on blades suggest the dozer experienced rough usage or severe operating conditions. Low operating hours on a dozer don’t necessarily equate to good condition if an operator has been abusive. While a generally good appearance is a favorable sign, new paint or replaced major components also could cover underlying machinery exhaustion.
3) Make a track undercarriage an inspection priority.
Looking ahead, this is where you can sink money. A new undercarriage in a midsized crawler dozer can cost upwards of $10,000. Hiring a true expert to probe and measure wear on undercarriage components could be a good investment. Sprockets, idlers, rails, rollers — they all are wear pieces and replacement of a few is expected. Wholesale rebuilding is another. Look underneath the chassis before you buy.
4) Do you know its maintenance history?
Looking at the dozer closely is important but looking at the papers on the machine is almost as important. (If there is no maintenance record available, you have to rely on observation alone. Good luck.) Was the dozer on a preventive maintenance schedule? Were usual service intervals honored? If a major component was replaced, was it from poor operation or just the failure of a part? Be curious.
Because dozers have been around for more than 90 years, makers of new models compete on price and quality, and used machines are widely available. This is in your favor. Still, the machines are pricey.
Manufacturers of crawler dozers offer a broad selection of sizes and prices. Hereafter are general categories of pricing:
Dozers — both tracked and wheeled — do not wear down because they were raced. Slow and steady characterizes their work, but operating hours add up regardless of pace. Prices reflect a dozer’s built-in durability. Any used dozer with fewer than a thousand hours is virtually new. Some general pricing guidelines:
Some Financing Options
1) Crawler or wheels
Of the two types, a wheeled dozer is the quicker and more nimble. This is important in certain applications, such as keeping haul roads clear in surface mines yet staying out of the way of haul trucks. Elsewhere in a mine, the pushing power of a heavy crawler machine is the better choice. A tracked machine can dig deep in early stages of road-building and a wheeled dozer can more speedily perform finish earth work. If mobility on a job site isn’t important — all the work being done at one place — go with a crawler.
2) Pyramid or oval undercarriage
In the beginning — and still mostly today — tracks on a dozer rotated on an oval carriage. Some manufacturers now offer what is termed a pyramid carriage with an elevated drive sprocket mounted higher than front and rear track idlers. The principal advantage of this triangular arrangement is that it keeps the drive train component out of mud and sand and clogs less easily. But it is a heavier undercarriage and more expensive to maintain. The oval design is fine for most applications and can produce more traction on hard surfaces.
3) Horsepower and weight
Horsepower and operating weight are nowhere more important than in a dozer. That is because together they translate into oomph! How much oomph! a dozer can generate determines how much dirt or rock it can dislodge and push away. Small dozers are in the 80-hp category and weigh 9 tons. The heaviest dozers are crawlers, with really big ones employing 360-hp engines to move 40+ tons. Really really big dozers approach 1,000 hp and weigh 115 tons or more. Somewhere in that range is an optimum size for you.
4) Blades and rippers
Dozers can be configured to accept a variety of attachments, but mostly they are hosts for blades, rippers and, sometimes, winches. As previously discussed, blades come in a handful of basic designs and widths. Rippers generally loosen soil for grading and are available in single shank or multiple-shank designs. A winch affixed to the rear of a dozer is handy for retrieving stranded vehicles, lowering tower structures and other pulling applications that leverage a dozer’s weight and stability.
5) Cabs and comfort
Classic photos show Seabees in World War II toiling in the sun at the controls of cab-less dozers. Today, most dozers have pressurized, factory-installed operator cabs with AC and heat units. Many used dozers, however, have simple rollover-protection open-air operator spaces, which is sufficient in some seasons. In repetitious applications like quarry and mining work, having an environmental-controlled workstation is an investment in productivity: Dust and noise can take a toll on operators after a few hours.
Case — Beginning as a Wisconsin threshing machine manufacturer, Case today offers a wide variety of construction equipment including six dozers ranging from 68 hp to 214 hp. A concept CTL dozer-loader, the DL450, awaits production.
Caterpillar — This Illinois manufacturer has a dozer history that dates to the beginning of dozers almost a hundred years ago. It offers six wheeled models, the largest a 907 hp 11-ton unit. Its crawler models number 17, from the 80-hp D3K2 to the 850-hp D11.
John Deere — This Moline, Ill., equipment manufacturer built its first crawler tractor in 1949 and it evolved into a dozer. The company today produces eight crawler models, the smallest the 60-hp, nine-ton 450K, the largest being the 350-hp, 47-ton 1050K.
Komatsu — — This Japanese firm produced Japan’s first crawler tractor in 1931 and its first dozer 12 years later. It markets 10 small crawler dozers—the smallest an 89-hp unit—12 midsize, 10 large, and three mining dozers including an 890-hp, 119-ton model.
Liebherr — This German manufacturing company was launched after World War II with the invention of the tower crane. Its construction industry products today include seven crawler dozers, the largest (the PR776 Litronic) an 80-ton, 1,000-hp model.
LiuGong (Dressta) — The Polish firm Dressta became a subsidiary of the Chinese company LiuGong in 2011. Today, the combined companies market 11 crawler dozers. Dressta’s vary from 93-hp to 500-hp. Of LiuGong’s three models, the largest is 344-hp.
Crawler dozers are a mainstay of the construction industry. Even the smallest of the machines can significantly impact a project with its ability to turn a raw site into a future landscape. Wheeled dozers are secondary earthmovers, and just as effective in their applications. Having one or more dozers in a company’s inventory of equipment means the firm has positioned itself to undertake serious construction projects. Carefully choosing a model and size of dozer is key to productivity.