Manufacturers advertise wheelbase according to the distance from the center hub of the steer axle, to the center-point between the two rear wheels on a three-axle truck. So, stick a ruler vertically in the ground right in between the two rear tires, and measure from there to the steer axle. The heavy tube fork was used on the snow plow dodge dana 60 front for several years, it was used on the ford bottom load dana 60 front in '76 and '77. The dana 70 open knuckle front used this same forging but was bored for the 3.56" tube, the 60 is 3.125 tube. steve differential eng. inc. Measure from the straightedge to the frame in front of the wheel and record the measurement. Next measure from the straightedge to the frame in back of the wheel and compare the two measurements. Both dimensions should be the same. Do the same on both sides of the trailer to complete your trailer axle alignment check. A spread axle trailer can haul 12k lbs on the steer axle, 34k lbs on the drive axles, and 40k lbs on the spread axles (or 20k lbs each axle). Although the total for this axle configuration is 86k lbs, you are still only allowed a total of 80k lbs gross. A common misconception is with a spread you load more toward the back.You can,, but the problem is a lot of guys get carried away with it.Having the spread is like sliding half of a sliding tandem up,thereby taking weight off the front of the trailer anyway.A diligent officer using seperate scales can find you over axle weight on the front ... On a combination of a truck tractor and semitrailer having not more than 5 axles, two (2) consecutive tandem axle assemblies shall be permitted at a gross permissible weight of 16,000 lbs. per axle, if there is no other axle within 9 feet of any axle of the assembly. and last axles of such consecutive sets of tandems is 36 feet or more. 4 If the distance between the centers of the first and third axles in a group of consecutive axles does not exceed 96 inches, the group is a tandem. 5 Maximum single axle 20,000 pounds; maximum tandem 34,000 pounds. State Kingpin to Rear Axle Limit Alabama 41 ft to the rearmost axle or a point midway between the two rear axles (only applies to semitrailers greater than 53 ft 6 in). California 40 ft to rearmost axle if semitrailer has two or more axles 38 ft to rear axle if semitrailer has one axle and does not extend forward of the rear of the cab. Connecticut *Commercial Financing provided by Currency Capital, LLC and loans made or arranged pursuant to California Finance Lenders Law license number 60DBO-56173. REAR SUSPENSION. The following is a general list of rear ends and their dimensions to help narrow the search for a possible candidate to replace the torque tube rear end or just get a better set of gears for highway driving. Axle spread measurement ... Measure from the straightedge to the frame in front of the wheel and record the measurement. Next measure from the straightedge to the frame in back of the wheel and compare the two measurements. Both dimensions should be the same. Do the same on both sides of the trailer to complete your trailer axle alignment check. Axle Length Typical quick-release axles are 11 or 12 mm longer than the spacing of the hub locknuts. This gives 5.5-6 mm of axle protrusion on each side. You don't actually need nearly this much, so for respacing hubs to wider spacing, if you're not adding more than, say, 5-6 mm of spacers, you don't need a new axle. Axle Spacings – the amount of space between axles, measured from the center of one axle hub to another. A standard 5 axle rig would be similar to 19-6 between the steer and first drive axle, 4-6 between the two drives, 35-0 between the last drive and the first trailer axle, and 4-6 between the two trailer axles.