Issue link: http://read.dmtmag.com/i/34501
If the governed speed for a vehicle originally equipped with 455/55R22.5 tires is 75 mph, the top speed with 11R24.5 will be (495/473) (75 mph) = (1.05) (75 mph) = 78.8 mph. The speedometer will read 75 mph when the vehicle is actually traveling 78.8 mph. Rule of Thumb: When going from a lower Tire Revs./Mile to a higher Tire Revs./Mile, the actual vehicle speed is less than the speedometer reading. When going from a higher Tire Revs./Mile to a lower Tire Revs./Mile, the actual vehicle speed is greater than the speedometer reading. 2. WHEEL DIAMETER Overall Width 5. TIRE CLEARANCES All clearances around a tire should be checked: • To the nearest fixed part of the vehicle, i.e., to parts that are not affected by spring deflection or steering mechanism. • To the nearest part of the vehicle, which can be moved, i.e. parts that are affected by spring deflection or steering mechanism. Consideration should be given to any additional clearance required by the use of chains. Minimum clearances recommendation: 1" a. Lateral Clearances Lateral clearance is the smallest distance horizontally Wheel Outset Wheel Inset Section Height Radius Width Diameter Loaded Radius Nominal Wheel C L Rim Overall Diameter Free between the tire and the nearest fixed point of the vehicle. Lateral clearance will be reduced by an increase in the offset of the inner wheel plus half of any increase in the tire section. Lateral Clearance X One® Deflection 3. RIM WIDTH An increase in the tire section may require a wider rim with a greater outset. 4. WHEEL OUTSET/INSET FOR DUAL WHEELS The minimum wheel outset required is determined by the tire minimum dual spacing. Outset is the lateral distance from the rim centerline to the mounting surface of the disc. Outset places the rim centerline outboard of the mounting (hub face) surface. Inset is the lateral distance from the rim centerline to the mounting surface of the disc. Inset places the rim centerline inboard of the mounting (hub face) surface. OFFSET for front wheels: When retrofitting steer axles with tires/wheels of a width different from the OE size, wheel offset must be considered. Wheel offset should be chosen to avoid interference with vehicle parts and also to avoid exceeding overall vehicle width regulations. Note: When using a 2" outset wheel, the MICHELIN® tire should be mounted so that the tire sits outward similar to an outer dual tire. However, use of outset wheels may change Gross Axle Weight Rating (GAWR). Consult vehicle manufacturer. Incorrect Lateral Clearance Correct Lateral Clearance Section Two: Mounting the Tire 31