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.
The tire is on a wheel that is attached to the vehicle with lug bolts & nuts. The lug bolts are anchored in a hub or axle flange depending on the type of vehicle. The lug bolts go thru the hub, that is a bit more expensive to replace then the bolts themselves. They are still called wheel studs.