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davidbrady · (This post was last modified: 11-05-2014 20:06 by davidbrady.)

The trick is to calculate the location of the center of gravity of the bus without the tongue weight, add the tongue weight and calculate the shift in the center of gravity, then take the sum of the moments about the steer axle assuming a 35/65 weight split on the tag/drive axles.

Assumptions:
Coach weight: 50000 lb
Wheelbase: 300"
Front overhang: 80"
Rear overhang: 100"
Tag to Drive axle spacing: 55"
Tag/Drive split: 35%/65%

Center of gravity location without tongue weight: 219" behind steer axle.
Steer: 15715 lb
Drive: 22285 lb
Tag: 12000 lb

Center of gravity with 1000lb tongue weight added: 225" behind steer axle.
Steer: 15056 lb
Drive: 23364 lb
Tag: 12580 lb

Delta off steer axle: 658.7 lb