Build a Complete Dexter Trailer Axle

Every Dexter axle beam Southwest Wheel sells ships as the beam only. That is true of a stock beam, a Pre-Configured Dexter Trailer Axle and a Custom Built Dexter Trailer Axle. Hubs, brakes, springs, hangers, U-bolts, wheels and tires are sold separately. This guide walks through each part you add to turn a beam into a complete, working axle, and how to keep every part rated for the same capacity.

If you have not picked a beam yet, start with Custom Built vs Pre-Configured Dexter Axles: Which to Order. If you need measurements first, use How to Measure for a Custom Dexter Trailer Axle.

Key takeaway

• The beam is only the start: A complete axle needs two hubs (idler or brake), a suspension kit, and two wheels and tires. Brakes are added with a brake kit.
• Match the spindle and bolt circle: Hubs and brake kits are sold by axle capacity, spindle and bolt circle. The wheels must use the same bolt circle as the hubs.
• A suspension kit covers the rest: One kit includes the springs, hangers, U-bolts, tie plates, nuts, shackles and bolts. A tandem kit adds the equalizers.
• Rate every part the same: The axle is only as strong as its lowest rated part. Springs, wheels and tires must add up to at least the axle capacity.
• Seats on stock beams ship loose: Southwest Wheel does not weld spring seats on stock beams. You weld them at your spring center before the springs go on.

Terms you need

• Idler hub: A hub with no brake.
• Brake hub: A hub that carries a brake drum or a disc brake rotor.
• Bolt circle: The number of wheel studs and the diameter of the circle they sit on, such as 5 on 4.5".
• 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.
• 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 and does not use the same hanger as a double eye spring.
• GAWR (Gross Axle Weight Rating): The load capacity of the axle system measured at the tires. It includes the wheels and tires and is limited by the lowest rated part.

What each beam includes

All three beam types are sold as the beam only. The table shows what comes on the beam and what you add.

Stock beams by capacity are listed in Trailer Axles, for example the Dexter 3,500 lb. Standard Spring Trailer Axle Beam. See Returns for the return policy.

Step 1: Choose your hubs

Every axle needs two hubs, one for each spindle. Pick idler hubs if the axle will not have brakes. Pick a brake kit in Step 2 if it will. A brake kit includes its own hub and drums, so do not order idler hubs as well.

Hubs must fit the spindle on your beam and use the bolt circle of the wheels you plan to run. The table shows the spindle and the bolt circles offered for each capacity.

A hub with parts includes the hub, bearings, seal, grease cap and lug nuts, and is sold individually, so order two per axle. Hubs ship without grease or oil. Pack the bearings and install the seal before the hub goes on the spindle. Shop Trailer Hubs with Parts or bare hubs in Trailer Hubs.

Before you pick a 5 on 4.75" or 5 on 5.5" hub, check that the wheel you want comes in that bolt circle.

Step 2: Add brakes

Dexter recommends brakes on all axles of any trailer design, and commercial trailers must meet federal rules that call for brakes on each wheel for most applications. Trailer brakes also help the tow vehicle brakes last longer.

Electric drum brake kits

Electric brakes are applied by magnets that get their power from the brake controller in the tow vehicle. One electric brake kit covers one axle. It includes two hub and drums, a left and right brake, bearings, seals, caps, spindle hardware, lug nuts and brake hardware.

• 2,000 lb.: 7" x 1-1/4" brakes, BK2KELE, for a 5 on 4.5" bolt circle. It needs a beam with a brake flange. The stock 2,000 lb. beam does not have one, so order the Dexter Custom Built 2,000 lb. Standard Spring Trailer Axle Beam with the brake flange option.
• 3,500 lb.: 10" x 2-1/4" brakes, for example BK545ELE-IPS. A self-adjusting version is BK545ELEAUTO-IPS.
• 5,200 lb.: 12" x 2" brakes, for example BK13ELE-IPS.
• 7,000 lb.: 12" x 2" brakes, for example BK42865ELE-IPS.
• 8,000 lb.: 12-1/4" x 3-3/8" electric or hydraulic brakes. The brakes and the hub and drums are sold separately. See the 8,000 lb. Standard Spring Dexter Trailer Axle Beam.

Shop Electric Trailer Brake Kits or Self-Adjusting Electric Brake Kits.

Hydraulic drum brake kits

Hydraulic brakes are controlled by the output pressure of a master cylinder. A hydraulic kit also covers one axle, for example BK545HYD-IPS for a 3,500 lb. axle. Shop Hydraulic Trailer Brake Kits.

DeeMaxx hydraulic disc brakes

DeeMaxx Hydraulic Disc Brakes are built for shorter stops than drum brakes. A disc brake uses a rotor in place of the drum and a caliper that grips the rotor when hydraulic fluid extends the piston. DeeMaxx kits are offered for 3,500, 5,200, 7,000 and 8,000 lb. axles.

A DeeMaxx kit is sold for one wheel, so order two per axle. The DM35KGOLD integral kit, for example, includes the rotor and hub, bracket, caliper, pads, bearings, seal, cap, wheel nuts and brake flange mounting hardware. The calipers come in Gold zinc or MAXX coating. The kits work with surge and electric over hydraulic actuators. See DM35KGOLD, or shop DeeMaxx Trailer Disc Brakes.

Brake flange notes

• The stock 3,500 lb. beam has a four-bolt brake flange. The stock 5,200 and 7,000 lb. beams have a five-bolt brake flange. The 8,000 lb. beam has a four-hole flange.
• The 5,200 and 7,000 lb. beams do not come with brake mounting bolts. The brake kits for those capacities include the mounting studs, nuts and lock washers.
• The stock 2,000 lb. beam does not have a brake flange, so it takes idler hubs only. For brakes on a 2,000 lb. axle, the custom 2,000 lb. beam offers a brake flange on the order form as an added cost, and the BK2KELE kit fits it.

Step 3: Add the suspension

Leaf springs attach to the axle with U-bolts, and the hangers are welded to the trailer frame. The parts that hold it all together normally come in a kit.

Single axle suspension kits

One suspension kit covers one axle. It includes the springs, hangers, U-bolts, tie plates, U-bolt nuts and lock washers, shackle straps, and shackle bolts and nuts. Because the kit already has the U-bolts and tie plates, you do not need a separate U-bolt kit.

• 2,000 lb.: 2000-KIT, two 1,250 lb. double eye springs, 3/8"-24 U-bolts.
• 3,500 lb.: 3500-KIT-SINGLE, two 1,750 lb. double eye springs, 1/2"-20 U-bolts.
• 5,200 lb.: 5200-SINGLE, 9/16"-18 U-bolts.

Shop Single Trailer Axle Suspension Kits. Kits without hangers are listed on each kit page for trailers that already have hangers.

Tandem axle suspension kits

A tandem kit covers two axles. It has four springs, the hangers for both axles and two equalizers, along with the U-bolts, tie plates and shackle hardware. Equalizers help transfer load from one axle to the other as the trailer travels over uneven ground.

• 3,500 lb.: 3500-KIT-TANDEM
• 5,200 lb.: 5200-TANDEM
• 7,000 lb.: 7000-KIT, four 3,500 lb. double eye springs
• 8,000 lb.: 8000-KIT-TANDEM, four 4,300 lb. slipper springs

Not every equalizer and hanger combination works together, so order the kit made for your axle capacity.

Buying suspension parts one at a time

If you are replacing a single part, each piece is sold on its own:

• Trailer Leaf Springs
• Hanger & Shackle Kits
• Trailer Equalizers
• U-Bolt Kits
• U-Bolt Plates
• Trailer Axle Seats

Spring ratings are listed per spring, and a pair carries one axle. Two 1,750 lb. springs equal one 3,500 lb. axle. U-bolts must fit the tube size of your beam. All of these parts are in Suspension Kits, Springs, Hangers, and Ubolts.

Spring seats

On a stock beam the spring seats come loose with the axle. Southwest Wheel does not weld spring seats on stock beams. You weld them at your spring center before the springs go on. Pre-configured beams have the seats pre-welded. On a custom beam, the order form sets welded or loose seats.

Step 4: Add wheels and tires

Each axle needs two wheels and tires. The two together must be rated for at least the axle capacity. For example, a 15" wheel and tire rated for 1,820 lb. each gives 3,640 lb. for the pair, which covers a 3,500 lb. axle.

• The wheel bolt circle must match the hub bolt circle.
• Never mount a tire with a higher capacity on a wheel with a lower capacity.
• Wheels are hub piloted or stud piloted. The cone angle of the lug nut must match the wheel.
• Do not mix radial and bias tires on the same trailer.
• The minimum overhang listed on each beam page is based on zero offset wheels.

Shop Trailer Wheels, Tires, and Assemblies. For more on ratings, see Choosing Trailer Axle Capacity: Hitch Weight, GAWR, Wheels and Tires.

Parts by axle capacity

Example: a complete 3,500 lb. single axle

Here is one way to build a 3,500 lb. single axle with 5 on 4.5" wheels:

1. Beam: One Dexter 3,500 lb. Standard Spring Trailer Axle Beam, a pre-configured 3,500 lb. beam, or a custom 3,500 lb. beam.
2. Hubs and brakes: Two 545LB1E hubs with parts for an idler axle, or one BK545ELE-IPS electric brake kit, or one BK545HYD-IPS hydraulic brake kit, or two DeeMaxx DM35KGOLD kits.
3. Suspension: One 3500-KIT-SINGLE. On a stock beam, you weld the loose seats at your spring center first.
4. Wheels and tires: Two 5 on 4.5" assemblies rated for at least 1,750 lb. each, such as the 128693WT31B-PMK.

For a 3,500 lb. tandem, order two beams, two sets of hubs or two brake kits, one 3500-KIT-TANDEM and four wheels and tires. Shipping is one charge for the entire order.

Keep every part rated for the same capacity

The GAWR of the axle is set by its lowest rated part. A beam rated for 6,000 lb. with springs rated 2,500 lb. each is limited to 5,000 lb. by the springs. Check each line before you order:

Installation reminders

• Dexter axles are directional. Install the axle with the front facing forward and the top facing up.
• Spring eyes and equalizers must be free to rotate.
• Torque the U-bolt nuts and wheel nuts per the Dexter service manual, using the tables below.
• On a new axle, check wheel nut torque at 10, 25 and 50 miles, and check brake adjustment at 200 and 3,000 miles.

U-bolt and suspension fastener torque

Per the Dexter service manual, torque the suspension fasteners to these values whenever they are loose or replaced. For 1/2"-20 U-bolts, the value depends on the nut: use the row for a hex nut or a flange nut.

Wheel nut torque

Per the Dexter service manual, start every nut by hand, then tighten in stages, following the torque sequence the manual shows for 4, 5, 6 and 8 bolt wheels. Torque before first road use and after each wheel removal, and recheck at 10, 25 and 50 miles. Use lug nuts that match the cone angle of your wheel.

The manual gives this chart for Dexter steel wheels made before June 2004. For other wheels, it says to get the torque level from the vehicle manufacturer, and never to exceed the stud limits in the second table.

Complete axle checklist

1. Pick the beam: stock, pre-configured or custom, at the capacity you need.
2. Note the spindle and pick a bolt circle that your wheels come in.
3. Choose idler hubs (two) or a brake kit (one electric or hydraulic drum kit per axle, or two DeeMaxx kits per axle).
4. Choose a single or tandem suspension kit for the same capacity.
5. On a stock beam, plan to weld the loose seats at your spring center yourself. Southwest Wheel does not weld seats on stock beams.
6. Choose two wheels and tires per axle rated for at least the axle capacity.
7. Check that the lowest rated part still meets your load.
8. Torque the U-bolt nuts and wheel nuts per the Dexter service manual and recheck the wheel nuts at 10, 25 and 50 miles.

Verify fitment before ordering or contact Southwest Wheel for assistance. Call 1-800-866-3336.

Frequently asked questions

Does a Dexter axle beam come with hubs?

No. Stock, pre-configured and custom beams are sold as the beam only. Hubs, springs, hangers and U-bolts are sold separately.

Do I need idler hubs if I buy a brake kit?

No. A drum brake kit includes two hub and drums, and a DeeMaxx kit includes the rotor and hub.

Can I put brakes on a 2,000 lb. axle?

Yes, with a beam that has a brake flange. The stock 2,000 lb. beam does not have one, so order the custom 2,000 lb. beam with the brake flange option and the BK2KELE electric brake kit. BK2KELE is for a 5 on 4.5" bolt circle.

How many DeeMaxx kits do I need for one axle?

Two. Each DeeMaxx kit is for one wheel.

Does a suspension kit include the U-bolts?

Yes. A suspension kit includes the U-bolts, tie plates, nuts and lock washers along with the springs and hangers.

What does a tandem kit add?

A tandem kit has four springs, the hangers for both axles and two equalizers.

Are the spring seats welded on a stock beam?

No. Southwest Wheel does not weld spring seats on stock beams. The seats ship loose, and you weld them at your spring center.

How do I know my wheels are rated high enough?

Add the ratings of the two wheels and the two tires on the axle. Each pair must equal or exceed the axle capacity.

Can I return the beam?

Stock axles, pre-configured and standard, are returnable within 30 days. Custom axles are built to spec and cannot be altered, changed, cancelled, or returned.

Welding new hangers for the suspension? See Hanger Spacing for Single and Tandem Leaf Spring Axles.

Southwest Wheel - Your Trailers Best Friend Since 1919.

References

• Trailer Axle Terminology, page 1 (Hub face, Spring center, Overhang), 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 8 (Brake Requirements; Wheels And Tires), page 9 (Running Gear Systems: Brake Types, Leaf spring, Axle Attachment Systems), page 10 (Running Gear Systems: Disc brakes), page 12 (Installation Suggestions).
• Dexter Trailer Axle Service Manual, 2,000 to 8,000 lb., page 5 (Getting Started - Setup and Adjustment), page 66 (Suspension Fastener Torque Values), page 71 to 72 (Torque Requirements), page 73 (Wheel Torque Requirements), page 74 (Maximum Wheel Fastener Torque).