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Full Truck or Tractor?

Sleeping Compartment?

Select a Vocation 

Truck or Tractor

Truck or Tractor

Imperial Weights

Metrics Weights

Desired Total GCW/GVW?


Desired Steer GAWR?


Desired Total Drive GAWR?


Steer Axle?

Select Front Axle Style

Rear Axle Style?

Select Rear Axle Style

                Lift Axle Required               

Weight > GAWR or Fed Bridge

Lift Axle/s?

Adding a lift axle allows you to increase GCW/GVW or shorten the wheelbase

No lift axle is being considered

Bridge Law/Permit? 

Select Applicable Bridge Laws or Permits 




Inches measured from centerline of front axle to center of the rear axle group defined under Rear Axle Style.

Rear Axle Spacing?

Spacing should be close as possible for best tire wear, at least 54 inches for most lift axle applications.

FAX to Back of Cab

Enter inches. Varies by model and axle setting. Used to arrive at wheelbase requirement and load space.

Cab to Body Gap

If vehicle is a semi-tractor then this field should be zero. Enter inches for trucks with a body.

Body Length

If vehicle is a semi-tractor then this field should be zero. Enter inches for trucks with a body.

Body Front to Bogie/Trunnion

Takes into account the gap value. Use a zero for Cab to Body Gap if you want to calculate cab to axle.

Cutoff/After Frame (Min)

Tractor values are static. Typically used for bodied trucks.



Overall Bridge

Review Bridge Law to verify the Overall Bridge for calculated Axle Count and compare to Desired GCW/GVW.

Axle Count

Calculated value. 

Minimum Tractor Wheelbase

Does not take into account lift axles, vertical exhaust behind cab/sleeper, or trailer swing/dip clearances.

Constraints Messages- click on constraint to address issue 

1. Typical front axle rating must exceed 13,000 lbs. with a sleeper larger than 75 inches.

2. Federal Bridge allows rounding up to next foot with half feet increments.

3. Reduce Desired Total GCW/GVW to eliminate lift axle requirement

Desired Total Drive GAWR

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