4. Routine maintenance, inspection and operational testing of the emergency generator and associated. components must be overseen by a properly trained person [see MSFC(07), Sec. 604.5; NFPA. 99(99), Sec. 3-4.4.1.1(b)3; NFPA 110(99), Sec. 6-4.7; NFPA 110(02), Sec. 8.4.7].
Replace the tires at least every 6 years. If you're not sure, the minimum replacement time that is recommended by the NHTSA is six years regardless of use, with 10 years being the maximum service life for tires. Check your owner's manual for specific recommendations related to your car.s the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).
This means fitting the right tyres and for safety ensuring that they are inflated to the manufacturer's recommended pressure. The legal limit for minimum depth of the tread on your tyres is 1.6 millimetres, across the central  of the tread around the complete circumference of the tyre. For safety reasons it is recommended that you replace your tyres before the legal limit is reached. Many vehicle manufacturers recommend replacing at 3 millimetres. At 1.6 millimetres in wet weather it takes an extra two car lengths (8 metres) to stop at 50 mph than if your tread was 3 millimetres. A regular check of your tyres can help you to avoid 3 penalty points and 2,500 in fines for having tyres worn beyond the legal minimum limit on your vehicle.