TESTING FOR TIRE NOISE Noise caused by the normal action of tire treads on various road surfaces is often confused with rear axle gears or other noises in the car The determination of whether tires are causing the noise complained of is relatively simple The car should be driven at various speeds and note taken of part throttle sudden acceleration and deceleration as axle and exhaust noises show definite variations under these conditions while tire noise will remain constant Tire noise is however most pronounced at speeds of approximately twenty or thirty miles per hour The tires may be further checked by driving the ear over smooth pavement with the tires at normal pressure and again over the same stretch of pavement when the tires have been inflated to fifty pounds pressure Reduce the tires to normal pressure one at a time to determine the faulty tire or tires This high inflation pressure should immediately be reduced to normal after test If the noise for which the test is being made is caused by tires it will noticeably decrease when the tire pressure is increased whereas axle noise should show no change in volume If on inspection the tires on the front wheels are found to be creating most of the noise the alignment of the front wheels should be checked as excessive tire noise usually results from low tire pressure incorrect alignment or from uneven tire wear