How to Align a Trailer Tongue to an Axle
by Nathan Fisher
A crucial step in the construction of a homemade trailer is properly aligning the tongue of the trailer --- the point that attaches to the tow vehicle --- precisely with the center of trailer's axle. There is virtually no tolerance for misalignment. If the tongue is not mounted properly to the frame, the trailer will not track properly behind the tow vehicle. The further the attachment point is off-center from the axle, the more the trailer will sway while being towed.
Step 1
Locate the center of the axle by measuring the distance between the inside edges of the wheel hubs, along the length of the trailer's axle. Divide the measurement in half and measure the result from the inside edge of either wheel hub to the center of the axle. For example, if the hub-to-hub measurement is 40 inches, half the distance would equal 20 inches. Measure in, along the axle, 20 inches from one wheel hub and mark with the pen. Double-check by measuring from the center mark to the inside edge of the opposite wheel hub. The measurements should be identical. If not, repeat the procedure.
Step 2
Measure the width of the front cross-member of the trailer's frame and divide the number in half. Measure the result from one edge of the front cross-member to the center of the front cross-member of the frame. As an example, if the front cross-member is 30 inches, half the distance would be equal to 15 inches. Measure in 15 inches from either edge of the front cross-member and mark the center point with the pen. Double check by measuring from the center mark on the front cross-member to the opposite end of the front cross member. The numbers should be identical.
Step 3
Locate the center of the trailer's hitch point (where the tongue of the trailer connects to the ball of the trailer hitch) by measuring the width of the ball-coupling latch that sits on top of the hitch ball socket. Divide the number in half and mark the resulting number on the latch.
Step 4
Push the tongue's attachment supports up against the front cross-member of the trailer's frame. Turn on the laser level and set the level on the center mark on the front cross-member of the frame. Align the laser with the center mark on the axle, then move the tongue assembly left or right to align the mark on the ball-coupling latch with the laser beam. The three center points of the axle, frame and hitch-point are now in perfect alignment.
Step 5
Mark the spots where the tongue attachment supports are lined up on the front cross-member of the trailer; the points where the tongue of the trailer will be connected (welded or bolted) to the trailer's frame.
References
- "Trailers; How to Design and Build"; M. Smith; 1993
Things You'll Need
- Tape measure
- Marking pen
- Laser level
Warnings
- Use caution when using a laser level. While it is perfectly safe to look at the beam, the laser will damage your retina if the end of the beam should strike you directly in the eye.
