How to Measure Your Trailer Axle for Replacement
The Short Version
Before you order a replacement axle, take these measurements off your existing one:
- Hub face to hub face (HF) — the overall width of the axle, measured between the wheel-mounting faces of the two hubs.
- Outside of bracket to outside of bracket (OSB) — the distance across the outer edges of the two mounting brackets, which has to match your trailer frame.
- Reverse mount? — if your axle is a reverse-mount setup, it's measured differently. Follow that part of the video and tell us it's a reverse mount when you order.
Measure twice. A fraction of an inch matters for fitment.
01 Hub Face to Hub Face
The hub face is the flat surface of the hub that the wheel bolts against. Measure straight across the axle from the hub face on one side to the hub face on the other. This number sets your overall track width — where your wheels sit relative to the fenders and frame.
- Take the wheels off so the tape sits flat against both hub faces.
- Keep the tape straight and taut across the axle — any sag adds length.
- Measure to the mounting face of the hub, not the end of the wheel studs.
02 Outside of Bracket to Outside of Bracket
Next, measure across the axle from the outside edge of one mounting bracket to the outside edge of the other. This is the dimension that has to line up with your trailer's frame rails — if it's off, the new axle won't bolt up where the old one came out.
- Measure from outer edge to outer edge — not bracket center to center, and not inside to inside.
- If the axle is still mounted, the outside of the brackets will usually line up with the outside of your frame rails.
03 Reverse-Mount Setups
Not every trailer has its axle mounted the standard way. If yours is a reverse-mount setup, the measurement is taken differently — follow the reverse-mount section of the video above, and note "reverse mount" when you order or contact us so we can confirm fitment before it ships.
Matching Your Numbers to Our Axles
Our axle listings use the same two measurements. A product named 94HF – 80OSB is a 94" hub face axle with 80" outside of bracket.
While you're under the trailer, also note the weight capacity (check the axle tag or sticker), the lug count and bolt pattern (e.g. 5 on 4.5", 6 on 5.5", 8 on 6.5"), and for torsion axles, the torsion arm angle (e.g. 22.5° down). Those, plus your two measurements, are everything you need to pick the right axle.
Got Your Measurements?
Match them to an axle in stock, or build one to your exact dimensions.
Not sure your numbers are right? Send us your measurements and a photo of your current axle — we'll confirm the fit before you order.
