Thin factory panels
Plastic and light-gauge metal covers can deflect, crack or tear when they contact rocks or deep ruts.
Devon 4x4 Buyer’s Guide
4x4 Underbody Protection Buyer’s Guide
Protect vulnerable components beneath your 4x4 with vehicle-specific skid plates, bash plates and underbody protection. This guide explains steel and aluminium construction, 3mm, 4mm and 6mm plate thicknesses, coverage, impact protection, servicing access and leading systems from ARB and RIVAL.
ARB and RIVAL systems
Steel and aluminium
3mm, 4mm and 6mm plates
Vehicle-specific protection
Protection Beneath the Vehicle
What is underbody protection?
Underbody protection uses shaped metal panels to shield vulnerable components beneath a 4x4 from rocks, ruts, tree stumps, compacted mud and other trail hazards. Depending on the vehicle and kit, protection may cover the radiator, steering components, engine sump, front differential, transmission, transfer case, AdBlue tank or fuel tank.
The panels are commonly described as skid plates, bash plates, sump guards or under-vehicle protection. A well-designed system does more than place a flat sheet beneath the vehicle. It uses pressed forms, folded edges, ribs, mounting brackets and carefully positioned fasteners to spread impact loads into approved structural locations.
Underbody protection does not make a vehicle indestructible. It reduces the chance of direct contact with sensitive components and can allow the vehicle to slide over an obstacle rather than catching on exposed housings, pipes or crossmembers.
Why Upgrade?
Why factory protection may not be enough
Factory undertrays are often designed around aerodynamics, splash protection, noise control and light road debris rather than repeated off-road impacts.
Exposed drivetrain parts
Sumps, transmissions, transfer cases and differentials may sit close to the vehicle’s lowest points.
Low front components
Radiator supports, intercooler plumbing and steering components can be vulnerable during steep approaches.
Ruts and hidden obstacles
Mud, water and vegetation can hide rocks, branches and eroded ground from the driver.
Remote-area reliability
Preventing damage beneath the vehicle can avoid fluid loss, immobilisation and expensive recovery.
Repeated trail use
Green laning, forestry work and overland travel expose the underside to more frequent contact than road driving.
Match Protection to Use
Who benefits from underbody protection?
The level of protection should reflect the terrain, vehicle weight, tyre size, driving style and consequences of component damage.
Touring and Green Laning
General off-road protection
Vehicle-specific protection provides useful insurance against unexpected contact during moderate trails, farm access, forestry work and overland travel.
- Engine sump and front protection are common priorities
- Weight and corrosion resistance matter on touring builds
- Service access should remain practical
- Factory ground clearance should be preserved where possible
Technical and Rocky Terrain
Comprehensive protection
Frequent contact and sharper impacts make broader coverage, stronger formed sections and secure chassis-mounted systems more important.
- Protect multiple drivetrain components
- Choose panels designed to slide over obstacles
- Inspect mounts after hard contact
- Driving technique remains essential
Know What the Kit Protects
Which components need protection?
Coverage varies by vehicle. Some kits are single panels; others form a multi-piece system running from the front crossmember to the transfer case or fuel tank.
Radiator and front support
Front panels help deflect branches and rocks away from low cooling-system components and supports.
Steering
Protection can shield steering racks, linkages and vulnerable components behind the front axle line.
Engine sump
A punctured or heavily deformed sump can cause immediate oil loss and serious engine damage.
Front differential
Selected kits protect exposed differential housings and nearby driveline components.
Transmission
Gearbox casings, sumps and cooling lines may be vulnerable behind the engine protection panel.
Transfer case
Transfer cases often sit centrally beneath the vehicle and may require a separate rear protection panel.
Fuel tank
Tank guards reduce direct contact with rocks and sharp obstacles on vehicles with exposed tanks.
AdBlue and auxiliary tanks
Modern vehicles may have additional low-mounted tanks and lines that need vehicle-specific protection.
Single Panels or Complete Systems
How much coverage do you need?
A front or sump guard may be sufficient for light trail use where one component is clearly the lowest and most exposed. It adds less weight and can be simpler to remove for servicing.
A multi-piece system extends protection rearwards across the engine, transmission and transfer case. Overlapping panels can create a smoother underside and reduce the chance of an exposed leading edge catching on an obstacle.
More coverage is not automatically better if the additional panels are unnecessary, poorly mounted or too heavy for the intended build. Choose the protection that covers actual vulnerable areas without compromising cooling, drainage, servicing or safe mounting.
Check exactly what is included
Product names such as “underbody protection kit” do not always mean full front-to-rear coverage. Confirm the number of plates and the component protected by each one.
Material Choice
Steel or aluminium underbody protection?
Steel and aluminium can both provide effective protection. Plate design, forming, mounting and coverage matter alongside material and thickness.
| Material | Main Advantages | Points to Consider | Typical Use |
|---|---|---|---|
| Steel | High impact resistance, strong formed sections and good resistance to gouging on sharp rock. | Greater weight; damaged coatings should be repaired to prevent corrosion. | Hard trail use, rocky routes and builds where maximum protection is prioritised. |
| Aluminium | Lower system weight and strong corrosion resistance, allowing thicker plates without the mass of equivalent steel. | Softer material can gouge or deform differently under sharp concentrated impacts. | Touring, overlanding and vehicles where payload or front-axle weight matters. |
Thickness alone does not define strength
A thinner pressed and folded panel can be more rigid than a thicker flat sheet. Material grade, folds, ribs, spans, bracket positions and fastener layout all affect the finished system.
Understanding Plate Thickness
3mm, 4mm and 6mm protection explained
The same thickness should not be compared directly across steel and aluminium. Material properties and panel design are different.
| Construction | Characteristics | Common Application | Important Note |
|---|---|---|---|
| 3mm steel | Strong impact protection with good rigidity when pressed, folded and supported correctly. | ARB vehicle-specific UVP systems and heavy-duty general off-road protection. | ARB uses 3mm laser-cut, pressed and folded steel on many UVP applications. |
| 4mm steel | Additional plate mass and resistance where the application or design calls for heavier steel construction. | Selected heavy-duty guards and vehicle-specific applications. | More thickness also means more weight; mounting design remains critical. |
| 4mm aluminium | Lightweight protection suitable for moderate touring and selected guards. | Weight-conscious builds where lighter coverage is appropriate. | Not directly equivalent to 4mm steel in impact behaviour or stiffness. |
| 6mm aluminium | Thicker aluminium construction balances increased panel depth with lower density than steel. | RIVAL vehicle-specific skid plates and comprehensive touring protection. | RIVAL commonly uses marine-grade aluminium in its underbody protection range. |
Do not choose by the largest number
A 6mm aluminium plate is not automatically stronger in every situation than a 3mm formed steel plate. Compare the complete engineered system rather than only the quoted thickness.
Panel Engineering
Why pressed and folded plates matter
Flat sheet metal can flex across a broad unsupported span. Pressed ribs, folded edges and shaped returns increase stiffness without requiring the entire panel to become excessively thick or heavy.
ARB describes its UVP panels as 3mm laser-cut, pressed and folded steel. The formed design helps maximise strength while recessed mounting bolts reduce exposed fastener heads beneath the vehicle.
RIVAL uses precision-cut marine-grade aluminium shaped around the vehicle’s underside. The thicker aluminium plate and formed construction provide protection while controlling system weight.
Vehicle Weight and Handling
Protection strength versus added weight
Underbody protection is mounted low, but its mass still counts toward payload, axle loads and gross vehicle weight.
Payload
Every plate, bracket and fastener reduces the payload available for passengers, luggage and accessories.
Front axle load
Front guards combine with bull bars, winches and dual-battery systems, so axle limits must be considered.
Suspension setup
Permanent accessory weight may affect ride height and suspension selection on heavily equipped vehicles.
Fuel consumption
Weight can influence fuel use, although smooth panel design may also reduce turbulence beneath some vehicles.
Touring priorities
Aluminium can preserve more payload where long-distance equipment and family loads already add substantial mass.
Impact priorities
Steel may be preferred where repeated hard contact and sharp rock exposure outweigh the penalty of added mass.
Clearance and Shape
Will underbody protection reduce ground clearance?
A well-designed vehicle-specific system follows the underside closely, but any added plate may alter the lowest point or ramp-over clearance.
Practical design goal
Maximum Coverage + Minimum Lost Clearance
The strongest plate is not useful if it hangs unnecessarily low or creates a leading edge that catches on obstacles. Vehicle-specific guards should fit close to the protected components and present a smooth path beneath the vehicle.
Inspect after severe impacts
A plate may absorb an impact by deforming. If it is pushed into a sump, transmission casing, exhaust or rotating component, stop and inspect before continuing.
Cooling, Drainage and Ventilation
Protection must not trap heat or debris
Underbody panels can influence airflow around the engine, transmission and exhaust. Vehicle-specific systems include openings, formed channels and spacing intended to preserve cooling and drainage.
Mud, grass and stones can collect above a plate after off-road use. Trapped debris may hold moisture against the vehicle, obstruct drainage or sit close to hot components.
Clean the space above the panels regularly, especially after deep mud, sand, forestry tracks and winter road use. Never add extra sheets or block designed openings without checking thermal and mechanical clearance.
Leading Protection Systems
ARB versus RIVAL underbody protection
Both brands offer vehicle-specific systems, but they use different material strategies and construction methods.
Pressed Steel Protection
ARB Under Vehicle Protection
ARB UVP systems are engineered for specific vehicles and commonly use 3mm laser-cut, pressed and folded steel. Coverage varies by application, with systems designed to shield steering, sump, transmission and transfer-case components.
- 3mm pressed and folded steel on many applications
- Laser-cut vehicle-specific panels
- Zinc-plated and powder-coated finish
- Recessed mounting bolts
- Removable panels for servicing
- Multi-piece coverage on selected vehicles
Marine-Grade Aluminium
RIVAL Underbody Protection
RIVAL produces precision-cut aluminium skid plates for a broad range of SUVs and pickups. The marine-grade aluminium construction provides substantial vehicle-specific coverage while limiting added weight.
- Marine-grade aluminium construction
- Thicker plate with lower mass than equivalent steel coverage
- Precision-cut vehicle-specific fit
- Strong corrosion resistance
- Separate plates and complete systems available
- Well suited to touring and overland builds
Quick Comparison
Which system suits your 4x4?
| Feature | ARB | RIVAL |
|---|---|---|
| Primary material | Pressed and folded steel | Marine-grade aluminium |
| Typical thickness approach | 3mm steel on many UVP systems; selected applications may vary | Thicker aluminium plate, commonly selected to balance protection and lower weight |
| Weight | Higher than comparable aluminium coverage | Lower for a similar protected area |
| Impact behaviour | Strong resistance to sharp impacts and gouging | Thicker plate spreads loads while reducing total system mass |
| Corrosion protection | Zinc plating and powder coating on ARB steel components | Natural corrosion resistance of marine-grade aluminium |
| Best suited to | Drivers prioritising formed steel strength and hard-use durability | Touring and overland builds prioritising coverage with reduced weight |
Choose by vehicle application first
The best brand is the one that offers the correct vehicle-specific coverage, approved mounting points and component protection for your model and intended use.
Accessory Compatibility
Bull bars, bumpers and underbody protection
Front protection panels may share mounting points with an aftermarket bumper or bull bar. Some systems are designed to work together, while others require specific brackets, trimming or different front plates.
Do not assume that an ARB UVP kit will fit every bumper, or that a RIVAL skid plate will fit every vehicle fitted with a RIVAL bumper. Compatibility depends on the exact vehicle, bumper version, model year and fitting kit.
Check recovery points, winch access, tow loops and jacking points as well. Protection panels must not obstruct rated recovery equipment or create unsafe access beneath the vehicle.
Correct Fitment
Underbody protection installation principles
Heavy panels must be supported safely during installation and attached only with the specified brackets, spacers and fasteners.
Confirm compatibility
Check vehicle model, year, engine, transmission, wheelbase, bumper and existing accessories.
Inspect mounting points
Clean factory threads and inspect crossmembers, brackets and captive nuts for damage.
Support the panels
Use suitable lifting equipment or assistance; large steel plates can be awkward and heavy.
Tighten in sequence
Fit all hardware loosely before alignment, then torque fasteners to the stated specification.
Maintain clearance
Check space around the sump, gearbox, exhaust, steering and moving driveline components.
Use supplied hardware
Incorrect bolt grades, washers or spacers can weaken the installation or damage the vehicle.
Protect wiring and hoses
Ensure no cable, brake line, fuel line or cooling hose is trapped above a plate or bracket.
Recheck after driving
Inspect torque and alignment after the initial journey and after the first off-road use.
Routine Maintenance
Servicing with skid plates fitted
Oil filters, drain plugs and transmission service points may sit above the protection system. Some guards include access openings, while others must be removed for servicing.
ARB highlights removable panels and recessed bolts as part of its UVP design. Easy removal is valuable, but fasteners should still be cleaned, inspected and tightened correctly after refitting.
Tell the workshop that aftermarket protection is fitted. Allow additional labour where panels must be removed, and ensure every bracket and spacer is returned to its correct position.
Inspection and Care
Underbody protection maintenance
Protection systems work in one of the harshest areas of the vehicle and should be checked after impacts, deep mud and winter road use.
Inspect after contact
Look for dents, cracks, distorted brackets, loose bolts and plates touching protected components.
Remove trapped debris
Wash mud, stones, grass and salt from both sides of the panels and around mounting points.
Repair steel coatings
Treat chips and exposed steel before surface corrosion spreads beneath the finish.
Check aluminium contact points
Inspect areas around steel brackets and fasteners for movement, wear or signs of galvanic corrosion.
Retorque fasteners
Follow the manufacturer’s interval and recheck after servicing or removing any panel.
Replace damaged hardware
Do not reuse stretched, heavily corroded or rounded fasteners beneath the vehicle.
Before You Order
How to choose the right underbody protection
Start with exact vehicle compatibility and the components that need protection, then compare material, weight, coverage and accessory compatibility.
Identify the vehicle
Confirm model, year, engine, gearbox, body style, wheelbase and market specification.
List vulnerable components
Check the sump, steering, transmission, transfer case, tanks and cooling components.
Choose coverage
Select a single guard or multi-piece system according to actual exposure and terrain.
Compare material
Balance steel impact resistance against aluminium weight savings and corrosion behaviour.
Check system weight
Include the plates in payload and front-axle calculations with other accessories.
Confirm bumper compatibility
Check shared mounts, brackets, recovery points, winch access and front-panel fitment.
Review service access
Understand which panels must be removed for oil changes and drivetrain servicing.
Plan professional fitting
Use suitable lifting equipment and follow all torque, alignment and clearance requirements.
Common Questions
Underbody protection FAQs
Answers to common questions about skid plates, material choice, thickness, fitment and maintenance.
Is steel or aluminium better for underbody protection?
Neither is universally better. Steel offers strong resistance to sharp impacts and gouging, while aluminium provides useful protection at a lower weight. Compare the complete vehicle-specific design, not material alone.
Is 6mm aluminium stronger than 3mm steel?
Not in every situation. The materials have different properties, and panel forming, unsupported span, brackets and mounting positions affect strength. Thickness figures should not be compared in isolation.
Why does ARB use 3mm steel?
ARB uses laser-cut, pressed and folded steel on many UVP systems. The formed shapes increase stiffness and strength compared with a simple flat sheet, while controlling overall weight.
What does RIVAL underbody protection use?
RIVAL describes its skid plates as precision-cut marine-grade aluminium. Exact plate thickness, coverage and kit contents vary by vehicle application.
Will skid plates reduce ground clearance?
They can alter the vehicle’s lowest point, but a good vehicle-specific design follows the underside closely and avoids unnecessary loss of clearance.
Can underbody protection cause overheating?
A correctly designed kit should preserve required airflow and clearance. Problems can occur if unsuitable plates are fitted, designed openings are blocked or mud and vegetation are allowed to accumulate above the panels.
Do I need full underbody protection for green laning?
Not always. A sump or front guard may cover the main vulnerable area on moderate routes. Full systems provide broader protection for vehicles used on rougher or more remote terrain.
Can I fit protection from one brand with another brand’s bumper?
Sometimes, but compatibility must be confirmed. Front plates and bumpers may share brackets or mounting points, and combinations can vary by vehicle and bumper version.
Can skid plates be repaired after an impact?
Minor deformation may be repairable, but cracked plates, stretched mounts or heavily distorted brackets may need replacement. Any repair must restore clearance, strength and secure mounting.
Do underbody plates need removing for servicing?
It depends on the vehicle and kit. Some include access openings, while others require one or more panels to be removed for oil, filter or gearbox work.
Should I remove factory undertrays before fitting protection?
Follow the fitting instructions. Some aftermarket systems replace factory panels, while others retain selected air guides, shields or mounting parts.
How often should skid plate bolts be checked?
Follow the manufacturer’s stated interval, check after initial fitment and inspect after hard impacts, rough tracks or any servicing that required panel removal.
Complete the Protection Package
Related 4x4 protection equipment
Protect the Vulnerable Parts
Choose underbody protection matched to your vehicle
Select the correct ARB or RIVAL system for your vehicle, terrain and existing accessories. Devon 4x4 can help confirm fitment, coverage, material and compatibility before you order.