We just explored the numerous measures Lexus has taken in order to make Lexus LS 600h – the world’s quietest vehicle – a reality.
In order to further reduce road noise, Lexus has also innovated in the area of the wheels. The result of that effort is noise-reduction wheels that are adopted to reduce weight, enhance rigidity, and suppress noise generated by the tires.
The weight reduction has been achieved through a hollow outer rim design. The weight saved by hollowing out the areas with no negative effect on the overall rigidity of the wheel has instead been allocated for reinforcement of the key areas.
The shape of the hollow structure is optimized, and a resonator hole has been installed, reducing the tire’s air column resonance. Five resonator holes for the 18-inch wheels or four resonator holes for the 19-inch wheels have been installed.
Tire air column resonance is generated as follows.
1. Tire deforms due to input from the road surface, and air pressure inside the tire changes.
2. Air inside the tires vibrate due to changes in pressure, and sound waves are generated in the tire’s air layer (air column).
Air forcefully enters and exits the resonator holes (friction is generated), and sound waves are converted to heat, causing a muffling effect.
The noise-reduction wheels are available for the LS series in the following sizes and tire dimensions (availability varies market by market):
Disc wheel size Tire size
18 x 7 1/2 J 235/50R18 97W 10 Spoke
18 x 7 1/2 J 235/50R18 97V
19 x 8J 245/45R19 98Y 10 Spoke
19 x 8J 245/45R19 102Y (summer)
19 x 8J 245/45R19 98V (all season)
Images courtesy by Lexus
To learn more about cars and sound/noise, get your copy of the Quiet Cars eBook – Your Guide to a Quieter Ride – plus join the Quiet Cars online community.
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