The short answer: the clamp attaches to the Grenadier's factory roof grab bar or rear ladder, not to the side gutter. Use the 2-inch for a side-facing mount on the roof grab bar or for horizontal ladder rails. Use the 3-inch for a roof-facing mount that needs clearance above the roof or for vertical ladder rails. Both share a 1.5-inch mounting face with two M8 holes spaced one inch apart.
Quick answer
2-inch: side-facing roof grab-bar mounts and horizontal ladder rails. 3-inch: roof-facing grab-bar mounts that need added clearance and vertical ladder rails. Match the actual mounting location and orientation first; then confirm door, body, sensor, and accessory clearance through the vehicle's full range of motion.
This guide explains the verified size distinction for the INEOS Grenadier versatile mounting clamps, shows how to make a conservative fit check, and separates the product's published specifications from application-specific decisions that still belong to the accessory manufacturer or installer.
1 What the two clamp sizes actually mean
The size choice is about how the clamp is oriented on the Grenadier roof grab bar or rear ladder, not the size or weight of the accessory. DVA lists the clamps for all Grenadier models, but the installation location and orientation still determine which version fits. Each order contains two clamps, and the live product listing currently offers both versions at the same price.
| Version | Verified DVA fitment | Use it when |
|---|---|---|
| 2-inch | Side-facing roof grab-bar mount; horizontal rear-ladder rails | The bracket faces outward from the roof grab bar or wraps a horizontal ladder rail |
| 3-inch | Roof-facing grab-bar mount; vertical rear-ladder rails | The bracket needs clearance above the roof or wraps a vertical ladder rail |
Do not select the 3-inch clamp simply because an accessory is bulky, and do not assume the 2-inch version is automatically the tidier choice. Start at the vehicle attachment point. A ladder-mounted tool may need either size depending on whether its bracket crosses the horizontal or vertical rails.
2 The shared mounting interface
Both clamp versions use a 1.5-inch-wide mounting face. The two accessory holes accept M8 fasteners and are spaced one inch apart. That common face makes the clamps adaptable to many brackets, but it is not a universal compatibility promise. Before buying or drilling an accessory plate, compare its hole pattern, fastener access, edge clearance, and installed orientation with those published dimensions.
DVA lists roof mounts, rear-ladder mounting, recovery tools, MOLLE panels, and containers as example uses. These are application ideas, not load ratings. The current product information does not publish a torque value or rated capacity, so this article does not invent either. A heavy or dynamic accessory must remain within the accessory maker's requirements and any limits that apply to the vehicle attachment point.
The product listing identifies clamp-install hardware as included, while M8 screws used to attach your accessory are not included. Plan the accessory-side fastener length and interface separately.
Roof grab bar: the factory tubular bar running along the roof edge; the clamp wraps around this bar rather than the gutter below it. Horizontal ladder rails: the rungs running left to right across the rear ladder. Vertical ladder rails: the two uprights carrying those rungs. Roof clearance: the additional offset needed to clear the roof surface and adjacent equipment.
3 A five-step fit check before installation
- Name the exact attachment point and orientation. Decide whether the bracket will face outward or upward from the roof grab bar, or wrap a horizontal or vertical ladder rail. This resolves the 2-inch-versus-3-inch question before accessory geometry complicates it.
- Mock up the complete assembly. Include the clamp, bracket, fastener heads, handles, and the accessory itself. A bracket that clears by itself can become a body-contact risk once a jack, panel, or container is installed.
- Cycle every moving part. Open the rear door fully and check the complete travel path. Look at the body panel, glass, door edge, hinges, seals, handles, and any adjacent equipment rather than judging clearance only with the door closed.
- Check the driving envelope. Confirm that the accessory does not obscure required lighting, the license plate, camera views, or sensor areas. Recheck overall height and width before entering garages, trails, or tight parking spaces.
- Follow the accessory instructions. Use the accessory manufacturer's fastener, loading, and installation requirements. Where those instructions do not cover a custom bracket, obtain qualified installation guidance instead of guessing at torque or capacity.
This order matters. Measuring the accessory first can send the selection process in the wrong direction; the clamp size is determined by the Grenadier attachment geometry. Clearance and load suitability come after that first choice.
4 What one owner installation teaches
First-hand Grenadier owner reports are useful when treated as observations, not universal specifications. Forum member parb documented buying the DVA brackets for a ladder-mounted Hi-Lift setup and later wrote:
“I'm pretty happy with my mount of my ladder using the DVA mechanics bracket.”
— parb, Grenadier Forum, edited November 19, 2024; source post
The same owner reported no rear-ultrasonic issue with that specific setup. That does not guarantee sensor clearance for a different accessory position. More importantly, parb also observed that a side-of-ladder orientation appeared likely to contact the vehicle when the door opened fully. The practical lesson is stronger than a blanket recommendation: mock up the exact assembly and test full door travel before final tightening.
In a separate thread, the same owner documented the initial Hi-Lift installation on the DVA bracket (source post). Neither post establishes a general load rating; treat both as observations from one installation, not a universal specification.
5 Choosing by common Grenadier use case
Side-facing roof grab-bar accessory
Start with the 2-inch version when the bracket faces outward from the factory roof grab bar. Confirm that the clamp wraps the grab bar and that the accessory and bracket remain clear of the gutter, roof edge, doors, and surrounding trim. Do not attach the clamp to the gutter itself.
Rear-ladder accessory on horizontal rails
Start with the 2-inch version. Pay special attention to rear-door travel and body clearance because the accessory can sweep toward the vehicle as the door opens. A rear-ladder location also deserves a visibility and sensor check with the accessory installed.
Rear-ladder accessory on vertical rails
Start with the 3-inch version. The rail orientation changes the clamp requirement, but the same clearance checks apply. Avoid assuming that moving an accessory from a horizontal to a vertical rail preserves the same offset or door-opening envelope.
Roof-clearance application
Use the 3-inch version for a roof-facing mount on the factory grab bar where the product's extra roof clearance is required. Configure the 2-inch or 3-inch variant on the product page and confirm compatibility with the rest of the roof system, including any Grenadier roof rack or crossbar equipment. Verify the vehicle's total height after installation.
6 Final selection checklist
- 2-inch selected for a side-facing roof grab-bar mount or horizontal ladder rails
- 3-inch selected for a roof-facing grab-bar mount needing added clearance or vertical ladder rails
- Accessory pattern checked against the 1.5-inch face and one-inch M8 hole spacing
- Accessory-side M8 screws selected separately
- No unverified torque or load figure assumed
- Rear door cycled through its full travel
- Body, glass, lights, camera, plate, and sensors checked
- Overall vehicle height and width remeasured
The safest buying decision is also the simplest: select the clamp from the Grenadier attachment point, not from the accessory name. Then treat the accessory, bracket, fasteners, clearance, and load as one complete system. For additional vehicle-specific equipment, browse the full INEOS Grenadier accessories collection.
Sources
- DVA Versatile Mounting Clamps product page, size, M8 interface, and included-item details. Roof grab-bar fitment terminology corrected by DVA Mechanics on September 8, 2026.
- parb, The Grenadier Forum, edited November 19, 2024, rear-ladder installation observation.
- parb, The Grenadier Forum, November 2024, initial Hi-Lift installation.
- parb, The Grenadier Forum, November 2024, full-door-opening clearance observation.
