2010 BMW 128 Owner's Manual - Page 197

heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law. The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.< of 1/6 in/4 mm, they become perceptibly less suitable for winter conditions. In the interest of safety, new tires should be installed. RSC - run-flat tires You will recognize run-flat tires by a circular symbol containing the letters RSC on the side of the tire, refer to page 196. Wear indicators in the base of the tread groove are distributed around the tire's circumference; the letters TWI, for Tread Wear Indicator, on the tire's sidewalls identify tires that incorporate these wear indicators. Once the tire tread has worn down to the wear indicators, the tire has worn to a depth of 1/16 in/1.6 mm. Wheel/tire damage Please note that low-profile tires cause wheels, tires and suspension parts to be more susceptible to road hazard and consequential damages. Unusual vibrations encountered during normal vehicle operation can indicate tire failure or some other vehicle defect. This can, for example, be caused by driving over curbs. The same applies to any other abnormal road behavior, such as pulling severely to the right or left. In these cases, reduce speed immediately and have wheels and tires thoroughly checked. To do so, drive carefully to the nearest BMW center or tire shop that works according to BMW repair procedures with correspondingly trained personnel. If necessary, have the vehicle towed there. Otherwise, tire damage can pose a lethal hazard to vehicle occupants and other road users.< M+S Winter and all-season tires. These have better winter properties than summer tires. XL Designation for specially reinforced tires. Tire condition Inspect your tires frequently for tread wear, signs of damage and for foreign objects lodged in the tread. Check the tread depth. Minimum tread depth The tread depth should not drop below 1/8 in/ 3 mm, although, for example, European legislation only specifies a minimum tread depth of 1/16 in/1.6 mm. At tread depths below 1/8 in/ 3 mm there is an increased risk of high-speed hydroplaning, even when only small amounts of water are present on the road surface. When winter tires wear down past a tread depth 195 Online Edition for Part no. 01 41 2 602 846 - © 08/09 BMW AG Reference Mobility Communications Entertainment Navigation Driving tips Controls At a glance