Equipment specifications: compare like measures
Equipment specifications become comparable only when the quantity, units, configuration and measurement conditions match. Keep an operating weight separate from a shipping weight, a tipping load separate from rated operating capacity, and engine power separate from PTO or hydraulic output.
Two published numbers can belong to different measures
Bobcat’s non-current S740 specification lists 3,100 lb rated operating capacity and 6,200 lb tipping load. The 3,100 lb difference is not an optional capacity increase: it separates a rated working measure from the tipping measure on that machine. Use the correct label before comparing it with another loader.
Bobcat S740 specification; lift-capacity measurement points.
Read what the weight already includes
Deere’s 245 P-Tier brochure specifies operating weight with a full fuel tank, operator, named bucket, arm, counterweight and shoe option. The excavator transport example shows why adding that same bucket again overstates the configured estimate. A different attachment needs its actual difference, not a second copy of an already included mass.
Use machine weight conventions to distinguish published configurations from the actual machine. For transport, establish the loaded configuration and use appropriate measurements where the decision requires them.
Choose the specification question
| Question | Reference |
|---|---|
| What does this capacity mean? | Lift points, tipping loads and load charts. |
| Which machine class fits the task? | Size classes and sizing to the work. |
| What do hours tell me? | Hours vs age: Hour-meter meaning and service evidence. |
| What will ownership cost? | Annual costs, utilization and cost per hour. |
| What tire fits? | Tire size and rating labels, checked against the model’s approved options. |
Hydraulic power links flow and pressure
The theoretical US-unit relation is horsepower = gpm × psi ÷ 1,714. An illustrative 20 gpm at 3,000 psi is 35.0 theoretical hp. It is not the cutter or implement’s delivered shaft power, and separately quoted maximum flow and pressure may not describe one sustained operating point.
Parker hydraulic power formulas; flow, pressure and power units.
Read the remaining measurement conventions
- Breakout and digging force
Breakout force and digging force describe forces produced by particular tool motions under a stated test basis. They do not give suspended-load capacity or promise that an excavator will break a particular soil or rock. Deere’s 245 P-Tier brochure shows the distinction on one machine with a 2.91 m arm: bucket digging force is 141 kN under its SAE label and 158 kN under its ISO label, while arm digging force is 110 and 114 kN respectively.
- Average ground pressure and contact area
Ground pressure and flotation figures describe a stated weight distributed over a stated contact area; they do not establish that a working surface can support a machine. In a simplified example, an assumed 20,000 lb carried on two rectangular track contacts, each 12 inches wide and 108 inches long, gives 7.72 psi average pressure. Increasing the assumed width to 18 inches gives 5.14 psi with the other inputs held constant.
- Drawbar pull, traction and slip
Drawbar pull and traction describe the force delivered through a towing point and the machine’s ability to transmit force to the ground. Engine horsepower cannot establish either by itself. Keep measured pull beside speed, slip, tires, ballast and the test conditions.
Nebraska Test 2139 for the John Deere 5075E two-post ROPS tractor, published in 2016, describes recording pull, speed, drawbar power, slip and fuel consumption; its 75% and 50% part-load runs are not wheel-slip recommendations.
- Travel speed, gradeability and slope limitations
Travel speed and gradeability need their units, configuration and stated operating basis. Percent grade is vertical rise divided by horizontal run times 100; degrees describe the slope angle, so the two numbers are not interchangeable. A 10 ft rise over 100 ft horizontal run is 10% grade, or about 5.71°, while 45° corresponds to 100%.
Those conversions describe geometry, not an approved slope for a machine. Deere’s 245 P-Tier brochure places a 70% (35°) off-level entry in its engine table and lists maximum travel speeds of 3.5 and 5.5 km/h for its two ranges.
- Earthmoving specification footnotes
Reading an earthmoving spec sheet requires the exact model, market, edition and measurement basis beside each number. Start with the task: access needs configured dimensions, transport needs actual carried mass, digging needs the tool and geometry, and lifting needs the applicable chart. Deere’s 245 P-Tier brochure shows why a footnote can change the comparison.
Its 25,500 kg operating-weight example includes the specified 871 kg bucket; adding that bucket again counts it twice.
- Crane chart configuration and radius
Reading a crane load chart starts with the individual crane’s approved configuration, load radius and required height. A maximum-capacity badge or boom-length headline cannot establish the capacity of another setup. Grove’s GMK3060L Imperial product guide carries an 85% label under ASME B30.5 and warns that its illustrative charts are not for operating the crane.
Use the individual crane’s applicable chart and instructions, including counterweight, support arrangement, boom or jib, working area, reeving and required deductions.
For an identified model, use the Tractor and compact equipment models: model specification directory. The interface and standards reference covers mounting, PTO and hydraulic connections.
The glossary of equipment terms defines the technical labels used with these figures.
Turn the job into a specification question
Write down the work before selecting the headline figure. Loading a pallet calls for the load, center and required placement; excavating a trench calls for the cutting geometry, access and material handling; operating a driven implement calls for the specified input and the installed connection. The same engine-power figure cannot settle all of those questions.
Use the quantity that describes the required output, then establish the configuration in which it is published.
Keep the heaviest or most restrictive individual task visible when deciding machine size. An acreage description does not identify every load or attachment on that property. A large total area can contain straightforward work, while a small site can require a particular reach, lift or access arrangement.
The machine-class and sizing guides help separate those requirements before model figures are compared.
Record the configuration beside the value
For a weight, list the publication's included equipment and operating condition. Then compare that list with the actual machine and the equipment being transported or used. A cab, different undercarriage, counterweight, loader, bucket or other attachment can change the configuration.
An identification plate, a brochure and a current weight measurement provide different information; do not assume every plate states the machine's present loaded mass.
For a capacity, retain the measurement point, height or radius and any required supporting arrangement. A tractor linkage entry, a loader entry and a crane chart use different configurations. Identify the attachment and the load arrangement that the figure covers.
If the required working position differs from the stated point, find the applicable information rather than treating the largest printed number as available everywhere.
For an output figure, keep the rating basis and the driven system together. Engine, PTO, drawbar and hydraulic figures describe different parts of the power path. Claimed and tested entries also need their own labels and conditions.
A calculated ratio between two listed values does not independently measure transmission efficiency or establish the output available throughout a working cycle.
Read hours, ownership cost and tires as separate evidence
An hour meter records the quantity defined by its installation; it does not record every service or the condition of every component. Review identity, meter history, calendar requirements and the work recorded in the service documentation. Compare like evidence between machines instead of assigning remaining life from the displayed number alone.
The hours-and-age guide connects that record with a used-machine inspection.
For cost, separate acquisition and delivery from annual ownership and operating expenses. Include the work needed to make a used package usable and compare the same scope in a rental quotation. Utilization changes the way annual fixed costs are spread over working hours.
The cost guides and calculator provide the structure; the purchase price by itself cannot establish a cost per productive hour.
For tires, record the installed size, construction and load information, then compare it with the machine's permitted options and operating requirements. The sidewall identifies the tire that is fitted, not automatic approval of that tire for the machine. Different axle combinations and fitted equipment need the applicable manufacturer's instructions rather than a visually similar replacement or an unsupported rolling-dimension substitution.
Carry source disagreements through to the decision
When references differ, first compare units, variant, publication date and the definition attached to each entry. Then distinguish a genuine configuration difference from a transcription or conversion problem. Keep both source labels while the discrepancy is resolved.
Averaging two incompatible values produces a new number without establishing which configuration it describes.
For a supplier inquiry, send the full model designation, relevant serial range, fitted equipment and the exact unresolved measurement. Ask for the document or chart that applies to that arrangement. A precise question about a loader position, PTO option or tire combination is more useful than an unqualified request for the specification of an entire model family.
Keep the unit system with the comparison
Read the unit label even when the numerical values look plausible. A volume entry needs its stated gallon or metric basis; a power entry needs its stated power unit as well as the rating definition. Pressure and flow units belong together in a hydraulic calculation.
A conversion changes the expression of a quantity, while a different test or configuration can change the quantity itself.
Do not repair an unexplained discrepancy by silently choosing the larger value or dropping a unit. Retain the original label, identify the applicable source and check the conversion separately from the model match. Apply the same checks to a photograph or seller's transcription: a readable number is only part of the specification when its heading, unit and conditions are missing.