Drum Brakes vs Disc Brakes on Trailers: Which Is Right for You?

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You hook up a gooseneck carrying a skid steer, gooseneck carrying a skid steer, bring the loaded trailer close bring the loaded trailer close to its rated capacity, and start to its rated capacity, and start down a long grade on State Road 46 down a long grade on State Road 46. As the combination. As the combination gathers speed, the trailer brakes gathers speed, the trailer brakes have to convert have to convert a tremendous amount of moving a tremendous amount of moving energy into heat. That is not the moment to discover energy into heat. That is not the moment to discover that the brake system, that the brake system, controller settings, or maintenance schedule controller settings, or maintenance schedule does not match the work does not match the work you are asking the trailer to do. The drum you are asking the trailer to do. The drum-versus-disc decision matters-versus-disc decision matters before the load is on, not during the descent.

before the load is on, not during the descent.

Both drum and disc systems stop trailers safelyBoth drum and disc systems stop trailers safely every day when they are correctly every day when they are correctly sized, properly adjusted sized, properly adjusted, matched to, matched to a compatible brake controller, and maintained. They do not, a compatible brake controller, and maintained. They do not, however, respond to however, respond to repeated heat, moisture repeated heat, moisture, high annual mileage, or hard, high annual mileage, or hard commercial use in exactly the same way. Here commercial use in exactly the same way. Here is an honest breakdown so is an honest breakdown so you can spec your you can spec your next trailer correctly from the start instead next trailer correctly from the start instead of paying to of paying to convert it later.

How Each System Works

Con>How Each System Works

Conventional electric drum brakes use twoventional electric drum brakes use two curved brake shoes mounted curved brake shoes mounted inside a drum. When the inside a drum. When the tow vehicle’s brake controller sends current tow vehicle’s brake controller sends current through the trailer wiring, an electrom through the trailer wiring, an electromagnet contactsagnet contacts the rotating armature surface inside the drum. That movement operates the rotating armature surface inside the drum. That movement operates a lever and cam that press a lever and cam that press the shoes outward against the drum’s inner the shoes outward against the drum’s inner braking braking surface. Increasing current to the magnet increases the braking surface. Increasing current to the magnet increases the braking force, provided the shoes force, provided the shoes are properly adjusted, the drum and are properly adjusted, the drum and magnet surfaces are in magnet surfaces are in good condition, and the brakes have been correctly good condition, and the brakes have been correctly burnished after installation.

Electric burnished after installation.

Electric drum brakes drum brakes do not need do not need hydraulic fluid, an electric hydraulic fluid, an electric-over-hydraulic actuator, hydraulic lines, or calipers-over-hydraulic actuator, hydraulic lines, or calipers. That relative. That relative simplicity is one reason they remain simplicity is one reason they remain the standard system the standard system on many utility, equipment, dump, flatbed, car on many utility, equipment, dump, flatbed, car-hauler, and enclosed trailers. Current forward self-adjusting assemblies-hauler, and enclosed trailers. Current forward self-adjusting assemblies maintain shoe maintain shoe-to-drum clearance during normal forward braking-to-drum clearance during normal forward braking after the initial setup after the initial setup,, although inspection and occasional manual although inspection and occasional manual correction may still be needed if correction may still be needed if performance changes performance changes.

Trailer disc brakes.

Trailer disc brakes use a rotor attached use a rotor attached to the wheel hub and a to the wheel hub and a hydraulic caliper that clamps friction pads against the hydraulic caliper that clamps friction pads against the rotor. On heavy equipment and rotor. On heavy equipment and gooseneck trailers, the usual setup is electric-over-hydraulic, gooseneck trailers, the usual setup is electric-over-hydraulic, commonly abbreviated EOH. The tow vehicle’s brake commonly abbreviated EOH. The tow vehicle’s brake controller sends an electrical signal to an actuator controller sends an electrical signal to an actuator mounted on mounted on the trailer. That actuator creates hydraulic pressure, which travels the trailer. That actuator creates hydraulic pressure, which travels through brake lines to the calipers.

through brake lines to the calipers.

The disc system’s clamping action is direct

The disc system’s clamping action is direct, and much of the rotor remains, and much of the rotor remains exposed to airflow. That helps the system release exposed to airflow. That helps the system release heat between heat between brake applications. The hydraulic pressure brake applications. The hydraulic pressure also gives EOH systems also gives EOH systems strong, strong, progressive brake progressive brake application when the controller, actuator, wiring, battery application when the controller, actuator, wiring, battery, hydraulic circuit, hydraulic circuit, tires, and axle, tires, and axle loading are all working together loading are all working together correctly.

Diamond C correctly.

Diamond C currently offers electric drum, electric-over-hyd currently offers electric drum, electric-over-hydraulic drum, and electric-over-hydraulic disc systems on qualifying configurationsraulic drum, and electric-over-hydraulic disc systems on qualifying configurations. Availability depends. Availability depends on the model, GVWR package, on the model, GVWR package, axle count, axle rating, and axle count, axle rating, and selected options. selected options. Current premium Current premium Diamond C lines such as the FMAX, HDT, Diamond C lines such as the FMAX, HDT, LPT, and LPX use Lippert axles as their LPT, and LPX use Lippert axles as their standard axle platform, with brake standard axle platform, with brake choices changing as choices changing as the trailer moves from 7,000 lb the trailer moves from 7,000 lb axle packages into heavier 8,000, 10,000, 12,000, axle packages into heavier 8,000, 10,000, 12,000, or 16,000 lb configurations.

< or 16,000 lb configurations.

Electric drums are common from 3,500 lb utilityp>Electric drums are common from 3,500 lb utility-trailer ax-trailer axles through much heavier commercial axleles through much heavier commercial axle packages. EOH disc brakes are available on selected packages. EOH disc brakes are available on selected heavy-duty configurations, heavy-duty configurations, including Diamond C trailers with total including Diamond C trailers with total GVWR ratings ranging from the GVWR ratings ranging from the mid-15,000 lb class mid-15,000 lb class into substantially heavier into substantially heavier FMAX builds FMAX builds. That means the decision. That means the decision should be based on the exact should be based on the exact trailer build, not a trailer build, not a general statement that every trailer above general statement that every trailer above or below one weight or below one weight needs a particular brake type.

< needs a particular brake type.

Heat: Where the Difference Shows Up Most

h2>Heat: Where the Difference Shows Up Most

Heat is the enemy of every friction brake system,Heat is the enemy of every friction brake system, and repeated high-energy and repeated high-energy stops are where the stops are where the practical difference between drums and discs becomes easiest practical difference between drums and discs becomes easiest to notice.

A to notice.

A drum encl drum encloses the shoes, springs, magnet, adjustoses the shoes, springs, magnet, adjuster, and friction surface inside a metal cylinder. During sustained brakinger, and friction surface inside a metal cylinder. During sustained braking, the drum absorbs heat, the drum absorbs heat while the enclosed design while the enclosed design limits direct limits direct airflow across the friction surfaces. If the driver airflow across the friction surfaces. If the driver rides the rides the brakes down brakes down a grade, approaches a grade, approaches the trailer’s capacity the trailer’s capacity repeatedly, or has repeatedly, or has the controller adjusted too the controller adjusted too aggressively, temperatures can rise enough to reduce friction aggressively, temperatures can rise enough to reduce friction and increase and increase stopping distance. The drum can also expand as it becomes hotter stopping distance. The drum can also expand as it becomes hotter, increasing the clearance, increasing the clearance the shoes must travel the shoes must travel before making before making full contact.

This loss full contact.

This loss of braking effectiveness of braking effectiveness is commonly called brake fade. It is not unique to is commonly called brake fade. It is not unique to drums, and disc drums, and disc brakes can also be brakes can also be overheated, but conventional overheated, but conventional trailer drums generally have trailer drums generally have less ability to shed less ability to shed accumulated heat during accumulated heat during repeated hard applications. repeated hard applications. Poor adjustment makes the problem worse because an under-adjusted shoe must move farther before contacting the drum, while an over-adjusted shoe can drag and create heat even when the driver is not braking.

A disc rotor exposes Poor adjustment makes the problem worse because an under-adjusted shoe must move farther before contacting the drum, while an over-adjusted shoe can drag and create heat even when the driver is not braking.

A disc rotor exposes a larger portion a larger portion of its braking surface to moving air. As the rotor turns of its braking surface to moving air. As the rotor turns, heat can, heat can move away from the pads and rotor move away from the pads and rotor more quickly than it can escape more quickly than it can escape from an enclosed drum assembly. That from an enclosed drum assembly. That does not make does not make an EOH disc system immune to fade an EOH disc system immune to fade, but it usually gives the brakes, but it usually gives the brakes better heat recovery and better heat recovery and more consistent performance during repeated heavy more consistent performance during repeated heavy stops, long descents, and high-mileage stops, long descents, and high-mileage commercial use.

Driving commercial use.

Driving technique still matters. The tow vehicle should be technique still matters. The tow vehicle should be in an appropriate gear before in an appropriate gear before the descent begins, engine braking the descent begins, engine braking should be used where available, and the driver should be used where available, and the driver should avoid continuously riding the service brakes should avoid continuously riding the service brakes. Trailer brakes. Trailer brakes and tow-vehicle brakes and tow-vehicle brakes are designed to stop the combination together. are designed to stop the combination together. Neither system should be expected to control Neither system should be expected to control the entire loaded combination by itself.

the entire loaded combination by itself.

For towing on mild terrain atFor towing on mild terrain at moderate weights, properly burnished and adjusted electric drums normally moderate weights, properly burnished and adjusted electric drums normally handle heat handle heat without difficulty. For without difficulty. For a trailer that spends its a trailer that spends its life near maximum life near maximum payload, crosses steep terrain payload, crosses steep terrain, makes repeated stops, makes repeated stops in traffic, or runs thousands of commercial in traffic, or runs thousands of commercial miles each month, the miles each month, the heat-management advantage of EOH discs becomes much heat-management advantage of EOH discs becomes much more valuable.

Stopping more valuable.

Stopping Performance

EOH disc brakes Performance

EOH disc brakes generally deliver strong, predictable braking because generally deliver strong, predictable braking because hydraulic pressure applies hydraulic pressure applies the calipers directly to the calipers directly to the rotors. The the rotors. The relationship between actuator relationship between actuator pressure and caliper clamping force pressure and caliper clamping force is progressive, which can make the is progressive, which can make the system easier to modulate during repeated system easier to modulate during repeated heavy applications. heavy applications. Conventional electric drums can also stop Conventional electric drums can also stop smoothly, but their performance is smoothly, but their performance is more sensitive to shoe adjustment more sensitive to shoe adjustment, burnishing, magnet condition, drum condition,, burnishing, magnet condition, drum condition, wiring voltage, and brake wiring voltage, and brake-controller calibration.

Brake type alone does not determine stopping distance-controller calibration.

Brake type alone does not determine stopping distance. Tire condition, tire. Tire condition, tire load rating, road load rating, road surface, trailer balance surface, trailer balance, tongue or gooseneck pin, tongue or gooseneck pin weight, axle loading, brake-controller settings weight, axle loading, brake-controller settings, tow-vehicle brakes,, tow-vehicle brakes, speed, and driver reaction speed, and driver reaction all matter all matter. A neglected disc. A neglected disc system with system with contaminated pads contaminated pads or air in the hydraulic lines or air in the hydraulic lines can perform worse than a properly maintained drum system. Likewise can perform worse than a properly maintained drum system. Likewise, new drum brakes, new drum brakes that have not been burn that have not been burnished may not produce their fullished may not produce their full expected braking force.

In expected braking force.

In wet conditions, water can temporarily reduce friction in wet conditions, water can temporarily reduce friction in either system. A drum can retain moisture around either system. A drum can retain moisture around the shoes and internal hardware, particularly after deep the shoes and internal hardware, particularly after deep water exposure or pressure water exposure or pressure washing. A rotating disc usually washing. A rotating disc usually clears ordinary road clears ordinary road spray from spray from the rotor more quickly, although a recently the rotor more quickly, although a recently submerged or heavily soaked submerged or heavily soaked disc system should disc system should still be tested carefully at still be tested carefully at low speed before normal towing low speed before normal towing resumes.

Current Diamond C configurations resumes.

Current Diamond C configurations illustrate why the exact model matters. The FMAX207 illustrate why the exact model matters. The FMAX207 is a 15,500 lb GV is a 15,500 lb GVWR single-wheel tandem gooseneck with two 7,WR single-wheel tandem gooseneck with two 7,000 lb Lippert axles and forward000 lb Lippert axles and forward self-adjusting electric drums self-adjusting electric drums as the base brake system, as the base brake system, with electric drum ABS and EOH disc choices with electric drum ABS and EOH disc choices available. The FMAX208 uses two 8,000 lb Lippert ax available. The FMAX208 uses two 8,000 lb Lippert axles at an 18,000 lb GVWRles at an 18,000 lb GVWR and currently and currently lists electric drum ABS lists electric drum ABS and EOH disc configurations. Qual and EOH disc configurations. Qualifying HDT, LPT, LPX, and heavierifying HDT, LPT, LPX, and heavier FMAX builds also offer EOH disc packages based on the selected FMAX builds also offer EOH disc packages based on the selected axle and GVWR package.

Diamond C has built axle and GVWR package.

Diamond C has built trailers in Mt. Pleasant, Texas trailers in Mt. Pleasant, Texas since 1985. Its current online configur since 1985. Its current online configurators show that brake equipment is tied to the completeators show that brake equipment is tied to the complete engineering package engineering package rather than treated as an rather than treated as an isolated accessory. Axle capacity, tires, suspension isolated accessory. Axle capacity, tires, suspension, coupler, frame, GVWR, and, coupler, frame, GVWR, and brakes must brakes must all work as one system.

all work as one system.

Many H&H

Many H&H utility utility, car-hauler, equipment, and enclosed configurations continue to use electric brakes, car-hauler, equipment, and enclosed configurations continue to use electric brakes on tandem axles, on tandem axles, while exact while exact brake availability varies by model and build. The same brake availability varies by model and build. The same is true across the is true across the trailer industry: electric drums remain the trailer industry: electric drums remain the dominant standard system, dominant standard system, while EOH discs are normally reserved for selected heavy-duty, while EOH discs are normally reserved for selected heavy-duty, high-mileage, or specialized applications.

high-mileage, or specialized applications.

Maintenance: Honest Numbers

Maintenance: Honest Numbers

Electric drums usuallyElectric drums usually win on system simplicity and roadside win on system simplicity and roadside familiarity. They have familiarity. They have fewer hydraulic fewer hydraulic components, most trailer components, most trailer shops understand them, and complete shops understand them, and complete backing-plate assemblies can often be replaced rather backing-plate assemblies can often be replaced rather than rebuilding every spring, shoe than rebuilding every spring, shoe, magnet, and adjuster individually.

As, magnet, and adjuster individually.

As a current a current parts-price reference, genuine parts-price reference, genuine Lippert 12-inch-by- Lippert 12-inch-by-2-inch electric brake assemblies for many 5,200 to 7,2-inch electric brake assemblies for many 5,200 to 7,000 lb axles are commonly priced around $80 to $115 per wheel000 lb axles are commonly priced around $80 to $115 per wheel before labor, shipping, drums, bearings before labor, shipping, drums, bearings, seals, and shop, seals, and shop supplies. Replacement supplies. Replacement shoe-and-lining kits may be near shoe-and-lining kits may be near $40 per wheel assembly, $40 per wheel assembly, although installing a complete backing although installing a complete backing plate can be more economical plate can be more economical once labor and the once labor and the condition of the magnet and hardware are considered. condition of the magnet and hardware are considered. Prices change, so the axle Prices change, so the axle identification tag identification tag and exact part number should always and exact part number should always be checked before ordering be checked before ordering.

Forward self-adjusting electric brakes.

Forward self-adjusting electric brakes do not require routine manual adjustment after every trip, but the do not require routine manual adjustment after every trip, but the term “self-adjusting” does not mean term “self-adjusting” does not mean maintenance-free. The wiring, maintenance-free. The wiring, magnets, lin magnets, linings, drums, bearings, seals, adjusters, and mounting hardware still need inspection. Lippertings, drums, bearings, seals, adjusters, and mounting hardware still need inspection. Lippert’s general service guidance uses’s general service guidance uses an annual or approximately an annual or approximately 36,000-mile inspection interval as a baseline for normal use, with 36,000-mile inspection interval as a baseline for normal use, with more frequent checks appropriate for commercial more frequent checks appropriate for commercial duty, repeated heavy duty, repeated heavy loading, water exposure, or any change in braking behavior loading, water exposure, or any change in braking behavior.

Disc brake pads can be.

Disc brake pads can be quicker to inspect because quicker to inspect because the caliper and the caliper and rotor are visible without rotor are visible without removing a drum. Current Lippert parts removing a drum. Current Lippert parts listings put a four listings put a four-pad set-pad set for certain 7,000 to 8,000 lb trailer for certain 7,000 to 8,000 lb trailer disc applications at disc applications at roughly $110 and a four-pad set for some roughly $110 and a four-pad set for some 10,000 to 16,000 lb applications at roughly $10,000 to 16,000 lb applications at roughly $140. That does not include140. That does not include labor, caliper service, labor, caliper service, hydraulic fluid, hoses, bearings, seals hydraulic fluid, hoses, bearings, seals, or rotor work.

Rotor, or rotor work.

Rotor and hub costs vary dramatically and hub costs vary dramatically with axle rating. with axle rating. A heavy 10,000 lb oil A heavy 10,000 lb oil-bath rotor-and-hub assembly can cost several hundred dollars-bath rotor-and-hub assembly can cost several hundred dollars per wheel, substantially more than the per wheel, substantially more than the inexpensive rot inexpensive rotors found on passenger vehiclesors found on passenger vehicles. Calipers, hydraulic lines, fittings, and the EOH actuator also. Calipers, hydraulic lines, fittings, and the EOH actuator also add service items add service items that a conventional electric drum system does not have.

that a conventional electric drum system does not have.

An EOH actuator is not simply a brake

An EOH actuator is not simply a brake controller mounted on the trailer. It is an electrically controller mounted on the trailer. It is an electrically powered hydraulic pump and reservoir assembly powered hydraulic pump and reservoir assembly that must receive adequate that must receive adequate battery voltage, a compatible battery voltage, a compatible controller signal, a sound controller signal, a sound ground connection, and a functioning breakaway circuit ground connection, and a functioning breakaway circuit. Air in the lines. Air in the lines, low fluid,, low fluid, a leaking fitting, a damaged hose a leaking fitting, a damaged hose, a weak trailer, a weak trailer battery, or an incompatible controller can reduce braking performance. If battery, or an incompatible controller can reduce braking performance. If the actuator or shared hydraulic circuit fails, the actuator or shared hydraulic circuit fails, braking can be reduced or lost across the wheel brakes braking can be reduced or lost across the wheel brakes connected to that circuit.

The connected to that circuit.

The tow vehicle’s factory controller tow vehicle’s factory controller must specifically support electric must specifically support electric-over-hydraulic operation. Some controllers-over-hydraulic operation. Some controllers designed only for electric designed only for electric drums will not activate drums will not activate an EOH actuator correctly or may produce fault an EOH actuator correctly or may produce fault messages, messages, delayed application, delayed application, or insufficient pressure. Diamond C’s current build or insufficient pressure. Diamond C’s current build information specifically advises using a information specifically advises using a compatible aftermarket controller when the factory-installed controller does not support hydraulic compatible aftermarket controller when the factory-installed controller does not support hydraulic trailer brakes.

trailer brakes.

Bottom line on maintenance: electric drums are familiarBottom line on maintenance: electric drums are familiar, mechanically straightforward, and inexpensive, mechanically straightforward, and inexpensive to repair with widely to repair with widely available parts. EOH discs available parts. EOH discs can offer longer can offer longer service life and lower service life and lower routine friction routine friction-material labor-material labor in high-mileage use, but the complete hydraulic in high-mileage use, but the complete hydraulic system costs more to purchase and requires technicians who understand trailer actuators, hydraulic bleeding, controller compatibility, and heavy axle components.

Corrosion: The Factor Most People Ignore

If your trailer is system costs more to purchase and requires technicians who understand trailer actuators, hydraulic bleeding, controller compatibility, and heavy axle components.

Corrosion: The Factor Most People Ignore

If your trailer is launched into water launched into water, operated near, operated near salt water, driven through Indiana salt water, driven through Indiana road brine, pressure washed frequently road brine, pressure washed frequently, or stored outside in a wet environment, corrosion deserves, or stored outside in a wet environment, corrosion deserves as much attention as stopping as much attention as stopping power.

Drum assemblies power.

Drum assemblies contain steel springs, hold contain steel spings, hold-down hardware, adjust-down hardware, adjusters, magnets, shoeers, magnets, shoe tables, and friction tables, and friction surfaces inside an enclosed housing. The surfaces inside an enclosed housing. The enclosure helps shield components enclosure helps shield components from ordinary road debris, but it can also retain from ordinary road debris, but it can also retain water, salt, mud water, salt, mud, or condensation, or condensation after contamination gets after contamination gets inside. A trailer inside. A trailer parked while parked while the shoes and the shoes and drum are wet can develop surface rust, sticking drum are wet can develop surface rust, sticking hardware, or shoes that temporarily adhere hardware, or shoes that temporarily adhere to the drum.

Disc rot to the drum.

Disc rotors and calipers are easier to seeors and calipers are easier to see, inspect, and rinse, inspect, and rinse, which, which is one is one reason disc brakes reason disc brakes are widely selected are widely selected for boat trailers and other repeatedly for boat trailers and other repeatedly immersed applications. Light immersed applications. Light surface oxidation can surface oxidation can appear on a cast appear on a cast-iron rotor after rain or washing and may clear during normal brake-iron rotor after rain or washing and may clear during normal brake application. Heavy p application. Heavy pitting, a sticking caliper, corroded slideitting, a sticking caliper, corroded slide hardware, damaged piston hardware, damaged piston seals, or flaking friction seals, or flaking friction surfaces are not normal surfaces are not normal and should be and should be serviced.

Exposure serviced.

Exposure cuts both ways. A disc rotor and cuts both ways. A disc rotor and caliper are open to road spray and salt, so caliper are open to road spray and salt, so ordinary automotive-grade components are not automatically corrosion-proof ordinary automotive-grade components are not automatically corrosion-proof. For repeated saltwater. For repeated saltwater immersion, corrosion-resistant cal immersion, corrosion-resistant calipers, coated or stainlessipers, coated or stainless components where specified components where specified, sealed electrical, sealed electrical connections, compatible brake connections, compatible brake fluid, and thorough fresh fluid, and thorough fresh-water rinsing are more-water rinsing are more important than simply choosing a important than simply choosing a rotor instead rotor instead of a drum.

For of a drum.

For Indiana winter use Indiana winter use, neither design, neither design should be ignored after should be ignored after brine exposure brine exposure. Rinse the under. Rinse the undercarriage and wheel-end components with lowcarriage and wheel-end components with low-pressure fresh water, allow-pressure fresh water, allow them to dry, and inspect them to dry, and inspect wiring, flexible wiring, flexible hoses, hard hoses, hard lines, fittings, ble lines, fittings, bleeders, caliper slides, drumeders, caliper slides, drum adjuster openings adjuster openings, and breakaway connections. Do not direct, and breakaway connections. Do not direct high-pressure water into seals, electrical high-pressure water into seals, electrical connectors connectors, bearing cavities, or drum, bearing cavities, or drum openings.

Diamond C openings.

Diamond C’s DM Difference Maker multi-stage coating system protects’s DM Difference Maker multi-stage coating system protects the trailer’s coated the trailer’s coated steel structure, but no frame steel structure, but no frame coating eliminates the need to service brake friction coating eliminates the need to service brake friction surfaces, axle hardware, hubs surfaces, axle hardware, hubs, hydraulic parts, hydraulic parts, or electrical connections. The brake system has, or electrical connections. The brake system has its own materials and its own materials and maintenance requirements.

In maintenance requirements.

In corrosive environments, discs corrosive environments, discs offer easier offer easier inspection and flushing inspection and flushing, while drums offer more physical, while drums offer more physical enclosure from ordinary enclosure from ordinary debris. The better ownership result debris. The better ownership result comes from selecting components intended comes from selecting components intended for the environment and maintaining them for the environment and maintaining them, not from assuming, not from assuming that either system can that either system can be exposed be exposed to salt indefinitely to salt indefinitely without attention.

Cost: Where the Budget Math Lands without attention.

Cost: Where the Budget Math Lands

On a typical

On a typical 7,000 lb GVWR tandem-axle utility trailer, electric drum 7,000 lb GVWR tandem-axle utility trailer, electric drum brakes are generally part of the base axle brakes are generally part of the base axle package. A good package. A good example is the Diamond C GTU, a premium tandem example is the Diamond C GTU, a premium tandem-axle bumper-pull utility trailer-axle bumper-pull utility trailer rated at 7,000 lb GVWR with rated at 7,000 lb GVWR with two 3,500 lb axles and a 4-inch channel frame two 3,500 lb axles and a 4-inch channel frame. A trailer. A trailer in that class does in that class does not normally need the expense or not normally need the expense or complexity of an EOH disc system for routine complexity of an EOH disc system for routine landscaping, property landscaping, property maintenance, or equipment maintenance, or equipment hauling on moderate hauling on moderate terrain.

Indiana law terrain.

Indiana law requires brakes on trailers over requires brakes on trailers over 3,000 lb GVWR under IC 9-19-3- 3,000 lb GVWR under IC 9-19-3-3. That rule establishes3. That rule establishes the need for an adequate braking system; it does not require the need for an adequate braking system; it does not require every qualifying trailer to have every qualifying trailer to have disc brakes. Electric disc brakes. Electric drums satisfy the requirement drums satisfy the requirement when they are properly equipped, maintained, and capable when they are properly equipped, maintained, and capable of controlling, stopping, and holding the trailer as of controlling, stopping, and holding the trailer as required.

The common claim that a required.

The common claim that a heavy-trailer disc upgrade costs heavy-trailer disc upgrade costs only $500 to $1,500 only $500 to $1,500 is no longer a reliable budgeting is no longer a reliable budgeting rule. On rule. On several current Diamond C heavy-duty configurations, the listed several current Diamond C heavy-duty configurations, the listed factory EOH disc option is approximately $2,500 to $ factory EOH disc option is approximately $2,500 to $3,100,3,100, depending on the model and axle package. For depending on the model and axle package. For example, current online configurations have shown roughly $3 example, current online configurations have shown roughly $3,105 on selected 7,000 lb axle,105 on selected 7,000 lb axle packages and about $2,500 on packages and about $2,500 on certain 8,000 or 10, certain 8,000 or 10,000 lb axle packages. Manufacturer pricing, regional factors, component000 lb axle packages. Manufacturer pricing, regional factors, component availability, model-year availability, model-year changes, and dealer pricing can alter the final amount.

That factory upp>

That factory upcharge covers morecharge covers more than pads and rotors. An than pads and rotors. An EOH build requires the EOH build requires the correct wheel-end components, actuator, reservoir correct wheel-end components, actuator, reservoir, hydraulic lines, fittings, wiring, battery support, hydraulic lines, fittings, wiring, battery support, breakaway integration, and compatible control, breakaway integration, and compatible control strategy. Con strategy. Converting an existing electric-dverting an existing electric-drum trailer later can cost more because the installerrum trailer later can cost more because the installer must source compatible components, remove the must source compatible components, remove the old system, route and bleed hydraulic old system, route and bleed hydraulic lines, verify hub lines, verify hub and spindle compatibility, and correct and spindle compatibility, and correct any controller or electrical any controller or electrical limitations.

The premium can limitations.

The premium can make economic sense on a trailer that accum make economic sense on a trailer that accumulates high annual mileage, routinelyulates high annual mileage, routinely works near capacity, crosses steep works near capacity, crosses steep grades, or experiences grades, or experiences frequent stop frequent stop-and-go commercial use-and-go commercial use. It is harder to justify on. It is harder to justify on a 7,000 lb utility trailer hauling a 7,000 lb utility trailer hauling lawn equipment a lawn equipment a few times each week over few times each week over flat or gently rolling roads. In flat or gently rolling roads. In that application, serviced that application, serviced electric drums can deliver dependable braking electric drums can deliver dependable braking throughout the trailer’s working life.

Do throughout the trailer’s working life.

Do not choose brakes not choose brakes by purchase by purchase price alone. Compare expected annual mileage price alone. Compare expected annual mileage, downtime cost, downtime cost, local parts, local parts availability, shop capability availability, shop capability, tow-vehicle controller compatibility, replacement, tow-vehicle controller compatibility, replacement-part prices, and how-part prices, and how long you long you plan to keep the trailer. A lower initial plan to keep the trailer. A lower initial price is price is not a not a bargain if bargain if the system is underspecified the system is underspecified for the work, and a premium for the work, and a premium system is not a system is not a good investment if its advantages will good investment if its advantages will never be used.

Which Trailer never be used.

Which Trailer Types Benefit Most from Disc Brakes

• • High-GVWR equipment trailers and goosenecks used>High-GVWR equipment trailers and goosenecks used commercially receive commercially receive the clearest benefit when they routinely the clearest benefit when they routinely operate near rated capacity, accumulate substantial operate near rated capacity, accumulate substantial mileage, or make repeated high-energy stops. Tra mileage, or make repeated high-energy stops. Trailers in the 20,000 lb-andilers in the 20,000 lb-and-higher class are-higher class are strong candidates for E strong candidates for EOH discs, but actualOH discs, but actual need still need still depends on terrain, duty depends on terrain, duty cycle, axle package, and manufacturer availability.

  cycle, axle package, and manufacturer availability.

  • Hotshot and long
  • Hotshot and long-distance flatbed-distance flatbed trailers can benefit because consistent braking trailers can benefit because consistent braking, quick heat, quick heat recovery, and easier pad recovery, and easier pad inspection become more inspection become more valuable as annual mileage increases valuable as annual mileage increases. Current Diamond C FMAX configurations. Current Diamond C FMAX configurations offer EOH disc choices on qualifying builds offer EOH disc choices on qualifying builds, including heavier axle packages intended for demanding, including heavier axle packages intended for demanding commercial service.
  • commercial service.
  • Horse and livestock trailers may benefit from aHorse and livestock trailers may benefit from a correctly tuned correctly tuned E EOH disc system when theOH disc system when the trailer is heavy trailer is heavy, frequently used, or operated in, frequently used, or operated in hilly terrain. Smooth braking depends on hilly terrain. Smooth braking depends on controller calibration and load balance controller calibration and load balance as much as much as brake type, so a well-adjusted electric drum system can as brake type, so a well-adjusted electric drum system can also provide controlled also provide controlled stops.

  stops.

  • Car haulers and enclosed cargo trailers used
  • Car haulers and enclosed cargo trailers used for valuable for valuable vehicles, race equipment vehicles, race equipment, tools, or commercial cargo may justify discs, tools, or commercial cargo may justify discs when high mileage and terrain make when high mileage and terrain make consistent braking more important than minimizing the initial purchase price.

  consistent braking more important than minimizing the initial purchase price.

  • Trailers used near or in
  • Trailers used near or in water, especially boat water, especially boat trailers that are repeatedly immersed, often benefit trailers that are repeatedly immersed, often benefit from corrosion-resistant disc components because the rotors and calipers can from corrosion-resistant disc components because the rotors and calipers can be inspected and rinsed more easily. The be inspected and rinsed more easily. The system still needs system still needs fresh-water flushing fresh-water flushing, corrosion-resistant hardware, and regular service.

  <, corrosion-resistant hardware, and regular service.

Electric drum brakesp>Electric drum brakes remain the practical choice for most remain the practical choice for most utility trailers, medium-duty utility trailers, medium-duty equipment trailers, dump trailers, enclosed cargo equipment trailers, dump trailers, enclosed cargo trailers, and flatbeds used on moderate terrain trailers, and flatbeds used on moderate terrain with predictable loads. Many current trailers with predictable loads. Many current trailers from Diamond C, Legend, Wells Cargo, H&H, and other established from Diamond C, Legend, Wells Cargo, H&H, and other established manufacturers use electric drums because they are effective, serviceable, compatible manufacturers use electric drums because they are effective, serviceable, compatible with common brake controllers, and economical to with common brake controllers, and economical to maintain.

GVWR by maintain.

GVWR by itself should not make the decision. A properly itself should not make the decision. A properly maintained 18,000 lb trailer used occasionally maintained 18,000 lb trailer used occasionally on flat roads may place on flat roads may place less thermal demand on its brakes less thermal demand on its brakes than a 14,000 lb trailer that runs every than a 14,000 lb trailer that runs every day in steep day in steep terrain. Start with the actual terrain. Start with the actual work, then work, then choose the system.

A Quick Comparison

>A Quick ComparisonFactor

>

< to adjustment during repeated hard braking

< with conventional proportional electric brake controllers

Factor	Drum Brakes	Drum Brakes	Disc Brakes
Disc Brakes
Heat management
Heat management	Enclosed design retains>Enclosed design retains more heat and more heat and is more sensitive is more sensitive to adjustment during repeated hard braking	Exposed rotor generally releases heat andtd>Exposed rotor generally releases heat and recovers more quickly between applications
Wet performance	Can>
Wet performance	Can retain water or contamination inside retain water or contamination inside the drum and the drum and may need careful low may need careful low-speed drying	Rotor-speed drying	Rotor usually clears road spray faster, but immersion still usually clears road spray faster, but immersion still requires testing, rins requires testing, rinsing, and inspection
ing, and inspection
Upfront cost	CommonUpfront cost	Commonly standard or included in the base axle package	Approximately $2,500 to $3,td>	Approximately $2,500 to $3,100 on many current Diamond C heavy-duty configurations;100 on many current Diamond C heavy-duty configurations; exact pricing varies
Brake exact pricing varies
Brake controls	Works controls	Works with conventional proportional electric brake controllers	Requires an EOH-compatibletd>Requires an EOH-compatible controller, actuator, hydraulic circuit, and adequate trailer electrical controller, actuator, hydraulic circuit, and adequate trailer electrical supply
Repair ease
Repair ease	Widely serviceable; complete backing-platetd>	Widely serviceable; complete backing-plate assemblies are readily available assemblies are readily available	Pads are	Pads are accessible, but actuator, caliper accessible, but actuator, caliper, rotor, fluid, and hydraulic, rotor, fluid, and hydraulic repairs require appropriate repairs require appropriate knowledge
Cor knowledge
Corrosion considerations	Internal hardwarerosion considerations	Internal hardware can retain moisture, can retain moisture, salt, or mud after contamination enters salt, or mud after contamination enters	Easier to inspect and rinse	Easier to inspect and rinse, but exposed rotors,, but exposed rotors, calipers, lines, and fittings can also calipers, lines, and fittings can also corrode
Best use corrode
Best use case	Moderate mileage case	Moderate mileage, predictable loads, common, predictable loads, common service access, and mild-to service access, and mild-to-moderate terrain	High mileage, repeated heavy stops-moderate terrain	High mileage, repeated heavy stops, long grades, demanding commercial use, or properly, long grades, demanding commercial use, or properly equipped water applications equipped water applications

What to Ask Before You Buy

What to Ask Before You Buy

When you are speccing a trailer, run through these questions:

<

When you are speccing a trailer, run through these questions:

1. What will the trailer actuallyol>
2. What will the trailer actually weigh when loaded, including attachments weigh when loaded, including attachments, fuel, tools, chains, pallets, fuel, tools, chains, pallets, spare tires, and other cargo?

<, spare tires, and other cargo?

3. How close will the normal loaded weight be to the trailerli>How close will the normal loaded weight be to the trailer’s GVWR and rated’s GVWR and rated payload capacity?
4. Does the regular payload capacity?
5. Does the regular route include long downhill route include long downhill grades, mountain driving grades, mountain driving, stop-and-go traffic, or repeated high, stop-and-go traffic, or repeated high-speed stops?
6. How many miles will the trailer travel each-speed stops?
7. How many miles will the trailer travel each year, and will it be used occasionally or as a year, and will it be used occasionally or as a daily commercial asset?
8. Will the daily commercial asset?
9. Will the trailer be immersed in trailer be immersed in water, exposed to salt water, driven through winter br water, exposed to salt water, driven through winter brine, pressure washed frequently, or stored outside?
10. Does the tow vehicle’s factoryli>
11. Does the tow vehicle’s factory brake controller explicitly support electric-over-hydraulic trailer brake controller explicitly support electric-over-hydraulic trailer brakes?
12. Can brakes?
13. Can nearby shops diagnose nearby shops diagnose and service the selected actuator, calipers, hydraulic circuit and service the selected actuator, calipers, hydraulic circuit, hubs, and axle components?
14. How important is roadside, hubs, and axle components?
15. How important is roadside parts availability compared parts availability compared with heat recovery and high with heat recovery and high-mileage performance?
16. What-mileage performance?
17. What are the current factory are the current factory-option price-option price, replacement-part cost, warranty terms, and expected downtime, replacement-part cost, warranty terms, and expected downtime for each system?

If the answers lean toward high for each system?

If the answers lean toward high annual mileage, frequent near-capacity loading, repeated annual mileage, frequent near-capacity loading, repeated stops, long grades, or properly equipped marine use, EOH discs deserve serious consideration. If the answers point to moderate loads, mild terrain, common service access, and occasional or predictable use, quality electric drums are usually the better value.

Remember that brake type does not change the trailer’s legal weight rating, the tow vehicle’s capacity, or the driver’s licensing requirements. For commercial operation, the stops, long grades, or properly equipped marine use, EOH discs deserve serious consideration. If the answers point to moderate loads, mild terrain, common service access, and occasional or predictable use, quality electric drums are usually the better value.

Remember that brake type does not change the trailer’s legal weight rating, the tow vehicle’s capacity, or the driver’s licensing requirements. For commercial operation, the federal Class A CDL threshold generally federal Class A CDL threshold generally applies when the combination has a GCWR or actual applies when the combination has a GCWR or actual gross combination weight of at least 26, gross combination weight of at least 26,001 lb and the001 lb and the towed unit has a GVWR or actual gross weight towed unit has a GVWR or actual gross weight over 10,000 lb. A trailer over 10,000 lb. A trailer exceeding 10,000 lb by exceeding 10,000 lb by itself does not automatically create a federal itself does not automatically create a federal Class A CDL requirement when the qualifying Class A CDL requirement when the qualifying combined threshold is not met, combined threshold is not met, although operating purpose, state rules, exemptions although operating purpose, state rules, exemptions, and actual, and actual weights still need to be reviewed.

Before towing weights still need to be reviewed.

Before towing, verify the certification labels, verify the certification labels on both the on both the truck and trailer, confirm the hitch and coupler ratings, test truck and trailer, confirm the hitch and coupler ratings, test the service brakes the service brakes and breakaway system, and breakaway system, and set the controller for and set the controller for the current load. Re the current load. Recheck the controller whenever the load changes significantly.check the controller whenever the load changes significantly. Brake lock Brake lockup, delayed application, weakup, delayed application, weak braking, pulling braking, pulling, noise, overheating, noise, overheating, or a controller fault should be investigated, or a controller fault should be investigated before the trailer returns to the before the trailer returns to the road.

The team at Spencer road.

The team at Spencer Trailers can walk you through current inventory and brake options across Diamond C, Legend Trailers can walk you through current inventory and brake options across Diamond C, Legend, and Wells Cargo trailer lines. Browse available[https://www.spencertrailers.com/all-inventory/](https://www.spencertrailers.com/all-inventory/)”>Browse available inventory here or reach out directly at (812) ers.com/contact-us/”>reach out directly at (812) 829-0226. If you are replacing a trailer and want to see what829-0226. If you are replacing a trailer and want to see what sold recently and how sold recently and how it was equipped, the recently sold pagewww.spencertrailers.com/recently-sold/”>recently sold page provides real-world examples of the provides real-world examples of the trailer sizes, axle packages, loading systems, and specifications trailer sizes, axle packages, loading systems, and specifications buyers are buyers are choosing.

So what is your next trailer carrying, how choosing.

So what is your next trailer carrying, how often will it run, and where is it often will it run, and where is it going? Those answers tell you far more about the right brake specification than a going? Those answers tell you far more about the right brake specification than a one-size one-size-fits-all marketing claim ever will.