Champion has several major families of full sized Graders-- The 720, 740 and 780 models (there are also 710, 730, and 750 models around). The weights of the machines are 33,000, 36,000 and 47,000 lbs respectively. Within these families, if the model ends in an "A" it is implied that the machine has an articulated frame, as in "720A", and if the model number ends in a '6' as in "726A" it is implied that it is a six wheel drive--articulated frame machine.
The VHP models feature an variable horsepower motor. In the above lineup, all of these graders are very close to the same physical size. The 720 series uses the smaller Cummins C8.3 engine set at 160 HP while the larger models use the Cummins M11 engine. In these models the electronic controls of the engine are interlocked to the powershift transmission so as to reduce the horsepower of the unit from 235 hp to 210 hp when the grader is in the lower gears. The 780A unit features a 14 foot blade and a wider wheel track than the others (9'2" overall width). Most of the extra weight is extra steel in the frame at critical locations. Consequently, the Champion 780A can be thought of as a construction sized grader while the 720 and 740 series can be thought of as maintenance graders.
Since this article was first written, Champion has become part of Volvo.
Clark bought up the old Austin-Western Grader company and in 1977 produced a model they called the 501S. It weighed in at 32,000 lbs and was all wheel steer, and all wheel drive. Power was either a tripple nickle Cummins (Vt-555) or a Detroit 6V-71N. either produced around 185 flywheel HP. Blades of 13' and 14' widths were available. They were apparently not big sellers, as this writer doesn't recall ever seeing one.
Allis Chalmers, and more recently Fiatallis have been in the road grader business for a long time. One of their more recent units is the FG35 which offeres either a rigid or articulated frame in the 31,000 lb class. It features the Cummins C8.3 engine set at 135 hp. and a 12 foot blade with 13' and 14' blade options. Fiatallis also produced larger FG 45 and FG 95 models with 150 and 180 hp. respectively.
Dateline: 1/5/2013: The FiatAllis name seems to be gone. New Holland seems to be the replacement, however New Holland Construction equipment doesn't appear to be in the North American Market. A couple New Holland graders appear to be available in other parts of the world.
Cat made the "G" series graders for many years. A 1971 'Spec' sheet descibes the 12G as an artiuclated frame machine with a Cat 3306 set at 135 hp. The weight was 31,000 lbs with cab and Scarifier and a 12' blade. (Notice any similarity to the FG35 from FiatAllis here?).
Meanwhile, the Cat 14G used the same engine set at 200 hp and weighed in at 40-45000 lbs depending on equipment, and featured a 14' foot blade.
The "G" series which was produced from 1972 to 1994 actually contained at least 6 models which included the following:
Turning the Clock back a little, Cat's last model before the "G" series was the 12F grader. It used the D333 engine set at 125 hp. and weighed in at 27,000 lbs. It was a transitional model for Cat. It featured power assisted mechanical controls for the blade. This means that it still had drive lines and gears moving the blade around instead of hydraulics, but instead of finger slappers, it had power assisted finger slappers which was supposes to reduce the finger slapping feature of the classic dog clutch driven blade control.
More than anyone, John Deere is the company that did something about road graders during the last 50 years. I give them credit for inventing the articulated grader, and hurrying the trend toward all hydraulic controls. For example the JD770 grader was a 142 HP unit with a weight of 29-33,000 lbs. depending on equipment. With no history (or old style tooling) Deere came in the market with the articulated grader with all electric blade controls. Except for the main blade lift controls all other blade functions were simply electric rocker switches. Instead of the large row of levers, there was a switch panel on the left, and 2 blade lift levers next to each other on the right. These machines sold well and have made Deere a major force in the grader market. To be sure the JD 770 was not their first grader, but the technology based on the Deere closed center hydraulics was there from the beginning. This writer recalls snorting at the first JD graders as being not big enough to push anything, but that problem was solved with this model.
Presently, Deere lists to basic models in a number of variations on their home page. Like Champion, they offer variable horsepower models in the 150 to 200 hp range. They do not, however, have a heavy construction grader.
Komatsu has Galion graders sharing their homepage. Galion is an old line domestic manufacturer, presumably part of the Dresser line which Komatsu for which Komatsu has an interest. Komatsu has a full line of graders from 30,000 lbs to 58,000 lbs. with most models being in the 30,000 maintenance class. All 3 Galions are of this lighter variety.
The great similarity in graders is no doubt accounted for in the fact that the biggest marker for graders is in the public sector for road maintenance. Public entities usually buy graders by a bid process so what you seen is a larger number of graders that hover around the typical 'bid specs' for government work. Presently that seems to be a machine that weighs around 15 tons, is 28 feet long, 8 feet wide, and has a 12 foot blade and from 150 to 180 HP. These 'bid graders' dominate the manufacturers offerings, as well as the used market. Graders more than 20 years old are likely to weigh a little less and have a bit less power. To be sure there are both larger and smaller graders, but there are few pieces of heavy machinery as standardized as the grader, and other than some weight and horsepower inflation, they have hardly changed in 50 years.