trailer axle diagram

How to Measure a Trailer Axle Leave a comment

Measuring your trailer axle correctly is very important when ordering a new one. The last thing you would want is to order a new axle and order the wrong size.  Most trailer axles are measure by the Hubface and Spring Center. Even with a bent trailer axle you usually can still get the correct measurements. See the Diagrams below to show how to correctly measure a trailer axle and if you have any questions or need more help call us at 602-292-9690.

  • Hub Face
    • The measurement from the face of one hub to the face of the other. (The hub face is where the back of the wheel sits against the face of the hub.)
  • Spring Center
    • The measurement from the center of one spring pad to center of the other. (Generally adding 2” to the Spring Center measurement can determine the Frame Width.) 
  • Axle Beams
    • Most 3,500 lb round tube axle beams are 2 3/8″ diameter.
    • Most 5,200 lb to 7,000 lb round tube axle beams are 3″ diameter.
  • Bolt Pattern
    • 3,500 lb axles are typically 5 lug.
      • The most common is 5 lug on 4.5″ bolt pattern.
      • There are 4 different 5 lug bolt patterns.
      • See our post here on how to measure a 5 lug bolt pattern.
    • 5,200 lb axle are usually 6 lug on 5.5″ bolt pattern
    • 7,000 lb axles are usually 8 lug on 6.5″ bolt pattern.


How to Measure a Trailer Axle
How to Measure Axle Hubface and Spring Centers


  • Check out our Documents Page for more information on trailer axles and even Safe Towing Tips!
  • Rockwell American Light Duty Axle Service Manual.

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