How to Measure the Hub Face & Spring Center on an Axle
How to Measure Hub Face and Spring Center on Your Trailer Axle
Need a replacement axle or checking specs on your trailer? Getting the axle’s hub face and spring center measurements right is critical for safe towing and proper fit. This quick guide along with the visual above will walk you through everything you need to know.
What You’ll Need
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Tape measure (at least 6 feet)
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Pen and paper or phone to record
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An extra helper (optional, but makes it easier)
Step-by-Step Instructions
Step 1: Measure Hub Face
Measure from the face of one hub to the face of the other hub. This is where the wheel touches the hub. Make sure you’re measuring outside to outside, not from backing plate to backing plate.
Step 2: Measure Spring Center
Measure from the center of one leaf spring to the center of the opposite leaf spring. This is usually where the spring attaches to the axle via U-bolts.
When calling about axles there are a few things we will need to know:
- What kind of axle do you have? torflex straight or drop
- Is the axle grease, EZ lube, never lube or oil?
- What is the capacity of each axle?
- What is the hub bolt pattern? For how to measure bolt patterns, see our resource page.
- 4-4.0
- 5-4.5
- 5-4.75
- 5-5.0
- 5-5.5
- 6-6.5
- 8-6.5 (studs 1/2″, 5/8″ or 9/16″)
- What is the hub face?
- What is the spring center?
- What kind of brakes do you have? idler (no brakes) electric, hydraulic, or disc
- What is the spring orientation? over or under
- What type of spring does the axle have and do you need new springs with the axle?