Suspension Tyres 1 Tyres 2 History of Wheels 1 History of Wheels 2 History of Wheels 3 History of Wheels 4 History of Wheels 5 History of Wheels 6 Tyre label History Sec. Wheels Winter Tyre Snow Chains All-weather Tyres Where to mount new tyres? Radial Ply Tyre Cross-ply Tyre Low Cross-section Tyre fitting Additional information Wheel Balancing Bus Wheel Balancing Tyre Production 1 Tire Production 2 Speedlimits Wheel Load Limits Roller Reststance 1 Stiction Emergency Running 1 Emergency Running 2 Tyre Press. Control 1 Tyre Control 2 Tyre Press. Control 3 Rims Alloy Rim Alloy Rim (production) Drop-center Rim Spoked wheel Rim Hump Rim (truck) Emergency Wheel Offset Wheel Positions Wheel-measuring Wheel Base Steering Offset Castor Steering axis incl. Wheel Alignment Relative Steering Angle Track Camber Obl./Side slip angle Axle Alignment 1 Axle Alignment 2 Axle Alignment 3 Tyre Calculation Inch -> mm Slip Axle Load Distrib. Payload Distrib. Roller Resistance 2 Wheels Wheels 2
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fine tread profilesolid wheel rimslow payloadclean road surfacesmooth road surfacefast driving
The road resistance is one of the constant driving resistances, always present, but not, e.g., like the wind resistance, which increases rapidly with the driving speed. This makes it difficult to reduce.
In this case, not only the friction between the road and the tyre plays a part, but also the movement within the tyre (churning). The tyre is, depending on internal pressure, burden and dimension, more or less compressed when rolling on the road surface. Even the driving speed is relevant, because at higher speeds, the dynamic wheel radius increases. Actually, one must also add the losses through friction, which e.g., rims with a lot of openings or tyres with a chunky tread profile cause when interacting with the surrounding air. Not to mention, in particular, the air-flow to cool the brakes. Just as one can hear the different noises that the same vehicle causes on various road surfaces, is, in these cases, also the road resistance different. This has to do with the road itself, but also with the surface covering, e.g., black ice. The previously mentioned factors can be slightly influenced by the driver, the following, hardly at all. They are partly dependent on the construction, and partly on the maintenance requirements. Belonging to this is the rolling friction in the sometimes adjustable wheel bearings and the friction within the brakes. The question here is, how much play does the brake disc or drum need, to prevent the brakes dragging shortly after the braking operation or permanently? Some modern braking systems also use the drag to keep the discs free of water.
