What size nut is on an axle nut?
Axle nuts don’t have a single universal size. Across the automotive landscape, the nut that secures the axle hub to the shaft typically ranges from about 27 mm to 36 mm across flats, with 30 mm, 32 mm and 34 mm being the most common on modern passenger cars. The exact size depends on the vehicle’s axle diameter, hub design, and the manufacturer’s torque requirements.
Common axle nut sizes
Automakers standardize several sizes, and most drivers will encounter a subset of these on everyday vehicles. The list below covers the most frequently seen across-flats measurements.
- 27 mm
- 28 mm
- 29 mm
- 30 mm
- 32 mm
- 34 mm
- 36 mm
These sizes cover a broad range of cars and light trucks, but yours may fall outside this set. Always confirm the exact size for your specific model before attempting removal or installation.
How to determine the exact size for your vehicle
To avoid guessing and risking damage to the nut, wheel, or hub assembly, follow these steps to identify the correct size for your vehicle.
- Check the vehicle’s owner’s manual or the official service manual, which often lists the axle nut size or torque specification.
- Look up your car model on a parts retailer or manufacturer site using the year, make, and model. Search for “axle nut” or “hub nut” to find the recommended size for your exact configuration.
- Inspect the existing nut and hub: remove the dust cap if present, then measure the nut across flats with a caliper or ruler, or try fitting sockets in increasing sizes to find the snug fit.
- If you’re unsure or the hub assembly uses a special fastener, consult a professional mechanic or parts counter at a trusted auto parts store to verify the correct size and torque.
Always tighten an axle nut to the manufacturer’s specified torque after installation, and replace any center caps or dust caps if removed. Using the wrong size or overtightening can strip threads or damage the hub assembly.
Notes on variation by vehicle type
While the sizes listed above satisfy many common passenger cars and light trucks, some models—particularly certain European brands, SUVs, or vehicles with unique hub designs—may require nonstandard sizes. In those cases, relying on the manufacturer’s documentation or a professional lookup is essential.
Safety considerations
Working with an axle nut involves wheel removal and lifting the vehicle. Take proper safety precautions: use a stable jack and jack stands, chock wheels, wear eye protection, and ensure the vehicle is securely supported before removing any fasteners.
Summary
There is no one-size-fits-all answer to “what size nut is on an axle nut.” Expect common sizes in the 27–36 mm range, with 30 mm, 32 mm, and 34 mm being the most frequent for modern cars. Always verify the exact size for your specific vehicle by consulting the owner’s or service manual, checking an official parts lookup, or inspecting the existing nut and hub. When in doubt, seek professional assistance to ensure correct sizing and torque.
