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How to Identify Your Old Trailer Axle and Order a Dexter Replacement
Replacing a worn or damaged trailer axle starts with knowing exactly what is under the trailer now. The replacement has to match the old axle's capacity, hub face and spring center, and fit the springs, hubs and brakes already on the trailer. Replacing an axle with a different size or capacity can affect alignment, suspension performance and safety, so match the original whenever you can.
This guide shows what to read off the old axle, what to measure when the label is gone, and how to turn those numbers into a pre-configured, stock or custom built Dexter axle. For the full measuring steps, see How to Measure for a Custom Dexter Trailer Axle.
Key takeaway
- Start with the label: The Dexter axle label is generally in the middle of the axle. It carries the axle description number.
- No label? Measure: Measure the hub face, the spring center and the brake size, then note the rest of the setup.
- Match the capacity: Use the capacity on the label, or the capacity you know you need. Do not estimate capacity from the size of the axle tube.
- Then pick how to order: A pre-configured Dexter axle if your numbers match a listed part number, a stock beam, or a custom built beam made to your measurements.
- Returns: Stock axles, pre-configured and standard, are returnable within 30 days. Custom axles are built to order and cannot be returned.
Terms you need
- Axle description number: A coded number on the axle label. It identifies the axle model, hub face, spring center, brake setup, lubrication and other features.
- Hub face: The measurement from the wheel mount on one hub to the same point on the other hub.
- Spring center: The distance from the center of one spring seat to the center of the other spring seat.
- Overhang: The hub face minus the spring center.
- Straight or drop: On a straight axle the spindle center is in line with the axle tube. On a drop axle the spindle center sits below the tube.
- Overslung or underslung: Overslung springs mount on top of the axle tube. Underslung springs mount under the tube.
- Double eye and slipper springs: A double eye spring has an eye at each end. A slipper spring has an open slipper at one end.
- Idler or brake: An idler axle has hubs with no brakes. A brake axle has brakes at the wheels.
- Bolt circle: The number of wheel studs and the diameter of the circle they sit on, such as 5 on 4.5".
Step 1: Read the axle label
Look in the middle of the axle. That is generally where the Dexter label is. If the label is there, write down the axle description number and the capacity printed on it. The capacity may be on the label, or it may be part of the description number.
The label has to be readable. If it is faded, painted over or torn, do not guess at the missing characters. Measure the axle instead, as shown in Step 2.
Every pre-configured Dexter axle at Southwest Wheel ends its name with the Dexter part number. That number matches the number on your old label only if the old axle was bought from Southwest Wheel. An axle bought from Dexter directly, or from another trailer manufacturer or distributor, will not show the same number. If your old axle came from Southwest Wheel, you can compare its number to the list in Pre-Configured Dexter Trailer Axles. Either way, still check the hub face and spring center before you order.
Dexter stamps a serial number in every axle, but only Dexter knows what the serial number means. Do not try to order from it. Use the label and your measurements instead.
Step 2: Measure the old axle
If the label is missing or cannot be read, the measurements become your replacement specifications. Take these with the axle still on the trailer if you can:
| Item | What to record | Why it matters |
|---|---|---|
| Hub face | Wheel mount on one hub to the same point on the other hub | Sets how wide the axle sits under the trailer |
| Spring center | Center of one spring seat to the center of the other | Lines the axle up with the springs and hangers |
| Brake size | Brake drum size, or no brakes (idler) | Tells you whether you need a brake flange and which brake kit fits |
| Capacity | From the label, or the capacity you know you need | The new axle should match it |
| Straight or drop | Spindle in line with the tube, or below it | Changes the trailer height |
| Spring mounting | Springs over the tube (overslung) or under it (underslung) | Overslung raises the frame. Underslung lowers it. |
| Spring type | Double eye or slipper | The springs and hangers have to match |
| Bolt circle | Number of studs and the circle they sit on | Your wheels must match the hub bolt circle |
Measure the hub face carefully. Do not guess this number. If you cannot get a clean measurement, call 1-800-866-3336 before you order.
Standard stocking axles come in 1" increments. Custom built axles can be fractional, so if your hub face or spring center falls between whole inches, plan on a custom built axle.
Check one more thing: is the old axle a leaf spring axle or a torsion axle? Every Dexter axle in this guide is a standard spring (leaf spring) axle. If your trailer rides on a torsion axle, see Torsion Axles instead.
Step 3: Confirm the capacity
Order the capacity printed on the old label, or the capacity you know the trailer needs. Do not estimate capacity from the size of the axle tube or the size of the parts on it. Also remember that an axle is only rated as high as its lowest rated part, so the hubs, springs, wheels and tires have to carry the same load.
Stock and pre-configured Dexter axles come in 2,000, 3,500, 5,200, 7,000 and 8,000 lb. capacities. Custom built beams also come in 4,400, 6,000 and 7,200 lb. If you are not sure what capacity the trailer needs, read Choosing Trailer Axle Capacity: Hitch Weight, GAWR, Wheels and Tires.
Step 4: Choose how to order the replacement
| Option | Order it when | What you get | Returns |
|---|---|---|---|
| Pre-configured | Your capacity, hub face and spring center match a listed Dexter part number in whole inches, and the old springs mount under the axle | Exact Dexter part number. Straight, cambered and underslung, with spring seats welded, E-Z Lube spindles and brake flanges | Stock item, returnable within 30 days |
| Stock beam | You need a straight or 4" drop beam in a stock capacity (2,000 lb. is straight only) and will weld the spring seats yourself | Beam with loose spring seats. Southwest Wheel does not weld seats on stock beams. | Stock item, returnable within 30 days |
| Custom built | Your hub face or spring center is a fraction of an inch, or your size, drop, capacity or options are not in the pre-configured list | A beam built to the numbers and options you enter on the order form, with a 45" to 95" hub face. Fractional measurements are allowed. | Built to order. Cannot be altered, changed, cancelled or returned |
All three are the beam only. Hubs, brakes, springs, hangers and U-bolts are sold separately, so reuse or replace them to match the old setup. If the springs mounted over the old axle, or you need welded seats on a custom beam, see Overslung vs Underslung and Camber: Spring Seat Options for a Custom Dexter Axle.
Notes for 2,000 lb. axles with brakes
The stock 2,000 lb. beam is straight only and does not have a brake flange, so it takes idler hubs only. If your old 2,000 lb. axle had brakes, the pre-configured 2,000 lb. axle with a 71" hub face and 58" spring center (Dexter 12460340) has a brake flange, and the custom 2,000 lb. beam offers a brake flange on the order form. The BK2KELE electric brake kit fits the 2,000 lb. brake flange and is for a 5 on 4.5" bolt circle.
How to choose
- If the label is readable, record the description number and capacity. If it is not, measure.
- Compare your capacity, hub face and spring center to the pre-configured list. Stocking axles come in 1" increments. If one matches and your springs mount under the axle, order that part number.
- If you only need a straight or 4" drop beam in a stock capacity and you can weld the seats, a stock beam works.
- If your hub face or spring center is a fraction of an inch, or your size, drop, capacity or options are not on the list, order a custom built beam made to your measurements.
- Match the hubs, brakes, springs and wheels to the new axle's capacity and bolt circle.
Replacement axle checklist
- Axle description number and capacity from the label, or a note that the label is missing
- Hub face
- Spring center
- Brake size, or idler (no brakes)
- Straight or drop
- Springs over or under the axle
- Double eye or slipper springs
- Bolt circle
- Leaf spring or torsion
- Single or tandem axle setup
Verify fitment before ordering or contact Southwest Wheel for assistance. Call 1-800-866-3336.
Installing the replacement
Dexter axles are directional. Install the new axle with the front facing forward and the top facing up. After it is installed, the axle must be square to the trailer within 1/2 degree, and on a tandem the axles must be parallel within 1/16" at the wheel centers.
Frequently asked questions
Where is the label on a trailer axle?
On a Dexter axle, the label is generally in the middle of the axle. It carries the axle description number.
Will the part number on my old label match the Southwest Wheel listing?
Only if the old axle was bought from Southwest Wheel. An axle bought from Dexter directly, or from another trailer manufacturer or distributor, will not show the same number. Check the hub face and spring center either way.
Can I order from the serial number on the axle?
No. Dexter stamps a serial number in every axle, but only Dexter knows what it means. Use the label and your measurements.
What if the axle label is missing or I cannot read it?
Measure the hub face, the spring center and the brake size, and use the checklist above. Those measurements become your replacement specifications.
Can I tell the capacity from the size of the axle tube?
No. Use the capacity on the label, or the capacity you know you need. Do not estimate capacity from the tube or the parts on it.
Should the new axle match the old one?
Yes, whenever possible. A different size or capacity can affect alignment, suspension performance and safety.
Can I return the replacement axle if it does not fit?
Stock axles, pre-configured and standard, are returnable within 30 days. A custom built axle cannot be altered, changed, cancelled or returned once the order is placed.
Does Southwest Wheel weld the seats on a stock beam?
No. The seats ship loose, and you weld them at your spring center. Pre-configured axles come with the seats welded.
Are Lippert and Dexter axles interchangeable?
Modern 8,000 lb. Lippert and Dexter axles are the same. That was not always the case, so if your axle is older, measure it and use the checklist above before you order.
Not sure if your size is stocked? Compare Custom Built vs Pre-Configured Dexter Axles: Which to Order.
Did the old axle have a drop? See Drop Axle vs Straight Axle: Deck Height Guide.
Moving or replacing the spring hangers? See Hanger Spacing for Single and Tandem Leaf Spring Axles.
Replacing the springs, hubs and brakes too? Plan them with Build a Complete Dexter Trailer Axle.
Found a match for your old axle?
Shop Pre-Configured Dexter Trailer Axles
Need a size that is not listed? See Custom Built Dexter Trailer Axles or call Southwest Wheel at 1-800-866-3336.
Southwest Wheel - Your Trailers Best Friend Since 1919.
References
- FAQs About How to ID Your Trailer Axle, page 1, sections 2, 3, 4, 5, 6 and 7.
- Trailer Axle Terminology, page 1 (Hub face, Spring center, Overhang), page 3 (Straight axle, Drop axle, Overslung and underslung), page 4 (Double eye, Slipper), page 5 (Idler and brake, Bolt circle).
- LIT-008-00, Dexter Axle applications guide, page 3 (Definition of Terms: GAWR), page 9 (Axle Types), page 12 (Installation Suggestions), page 19 (Axle Alignment).
