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on the scribe line, and measure the distance between the lines on the left and right tire at the paint can height. Subtract front from rear: positive result indicates toe-in, negative is toe-out. At this paint can height: total toe-in should be positive +1 mm so that the tires will run in a straight line under a dynamic, loaded condition. Recommended toe setting is +1⁄16" (1.5 mm). 6. If checking for camber, with wheels straight ahead, drop a plumb line off the front fender over the tire assembly center and measure the distance, using millimeters, between the string and rim flange at the top and bottom. Divide your difference by 10 to convert millimeters to degrees. Use the paint can to extend out from the fender if necessary. Repeat the procedure on the other steer position. Consider any floor slope, mismatched air pressures, or mismatched tread depths. Rear of Vehicle 1.Measure for drive axle offset by measuring, at each drive axle wheel position, from the inner wheel flange to the inside of the frame rail (tolerance: 3⁄16" or 5 mm side to side). 2. Check ride height by measuring the distance from the lower part of the frame rail to the bottom of the air spring (bag) housing. Verify manufacturer’s recommendation for vehicle type. ATTACC PLUS WORKSHEET Front Tandem Axle Skew String to Wheel for Drive Axle Thrust Spring to Flange 3.Measure for tandem axle skew by measuring between the rim flanges. Kneel between the outside of the tires. Hook the metric tape measure at hub-height on one, and by using a swinging arc on the other, determine the shortest distance between them. Take a similar measurement on the other side of the vehicle (tolerance is 1⁄8" or 3 mm between axle ends). 4.Measure for drive axle thrust by using the string from the front drive axle to the steer position. Attach the string to the drive tire at hub-height, bring it across the rear sidewall, move to the steering axle, bring the string in toward the front rim until it touches the drive tire’s front sidewall, and measure the distance between the string and disc face of the rim (just below the dust cap). Repeat this method on the other side. With all data recorded, review measurement of drive axle offset. Any significant drive axle offset, if found (± 3⁄16" or ± 5 mm), must be factored into the readings of drive axle thrust as determined above by adding or subtracting the offset from the appropriate side (string to front wheel flange measurement ± offset). Draw a picture of the steer and drive axle orientation using recorded axle skew measurements. Drive axle skew tolerance is based on wheel base. 19⁄32" or 15 mm < 150", 3⁄4" or 20 mm 150-200", 1" or 25 mm > 200". Drive Axle Offset Drive Axle Offset Steer Offset Grease Zerk to U-Bolt Drive Axle Offset Drive Axle Offset Steer Offset Grease Zerk to U-Bolt Spring to Flange String to Wheel for Drive Axle Thrust Front Tandem Axle Skew Section Nine: Appendix 119