The level of accuracy depends on the application. Generally Â±0.5 to 1C accuracy is sufficient in the food industry whereas the pharmaceutical industry may require Â±0.2 to 0.5C accuracy or better. It is important to note the scale used in comparisons though Â±0.2C accuracy is not the same as Â±0.2F accuracy.
All vehicles towing trailers must have chains on one drive axle. Trailers with brakes must have chains on at least one axle. Requirement 2 (R-2): Chains are required on all vehicles except four-wheel-drive vehicles under 6,500 pounds gross weight and equipped with snow tires on all four wheels. Chains for one set of drive wheels must be carried by four wheel-drive vehicles using snow tires. Requirement 3 (R-3): Chains are required on all vehicles without exception. R-1 and R-2 are the most common conditions.
Many car buyers are confused by the matter of which wheels actually drive the vehicle, and which is best for their particular needs. There are four main choices: front-wheel drive, rear-wheel drive, four-wheel drive or all-wheel drive. Each has its advantages, and no single layout is best for all situations. It will help to understand a device known as the differential.