Until around 1978, tire sizes were indicated by alpha-numeric codes, such as D78-14. Then, with the adoption of the metric system, the codes changed drastically. Today, the new codes are much longer and provide more information. Tire dealers are required by law to have leaflets available that explain tire grades and ratings. The leaflets also tell you which metric codes replace the old alphanumeric designations.
For example, here’s the information provided by a common "P-metric" tire code, P205/75R-14:
The selection of an impact wrench should be based on the torque and speed required as well as the volume of work. An extra heavy duty tool is not required for a shop that changes four tires per day. It is required for high volume shops. The heavy duty or extra heavy duty wrenches are recommended for truck wheel service.
The portable machine tools classified as either cutting took (straight and machine tools, can quickly and easily be moved to the angle hand drills, metal sawing machines, and metal cutting workplace to accomplish machining operations. The accuracy shears) or finishing tools (sanders, grinders, and polishers). of work performed by portable machine tools is dependent upon the user’s skill and experience.
Gear pumps (with external teeth) (fixed displacement) are simple and economical pumps. The swept volume or displacement of gear pumps for hydraulics will be between about 1 cm3 (0.001 litre) and 200 cm3 (0.2 litre). These pumps create pressure through the meshing of the gear teeth, which forces fluid around the gears to pressurize the outlet side. Some gear pumps can be quite noisy, compared to other types, but modern gear pumps are highly reliable and much quieter than older models.