This Viking 12" Concave Roller drops straight into a trailer setup that runs a 12 inch keel roller. The 95mm diameter and concave shape keep the keel tracking in the middle when you winch the boat on. A 25mm bore lines up with common roller shafts, so you can swap worn rollers without changing brackets. The black rubber body gives a solid contact patch along the full 305mm length. The roller uses moulded rubber sized to a 95mm outside diameter for predictable compression under load. The 25mm bore is straight and smooth to match standard steel pins used on local boat trailers. The 12 inch long body suits many centre-line keel supports across Aussie boat ramps. The black finish handles road grime and salt spray while staying simple to hose off after a run. This is smart buy trailer gear for regular towing.

• Brand: Viking
• Concave keel roller design
• Length: 12 inches (approx. 305mm)
• Outside diameter: 95mm
• Bore size: 25mm shaft compatibility
• Material: black rubber construction
• Suits marine trailer rollers and skids
• Helps centre keel during winching
• Cushions hull contact along roller length
• Ideal as replacement roller on matching brackets

Q: What shaft size does this 12" concave roller suit?

This roller suits a 25mm shaft or pin. The internal bore of the roller is specified at 25mm, so it slides over a 25mm diameter shaft with minimal play. Matching the shaft size to the bore keeps the roller aligned under load. Always check the existing pin size on your trailer before ordering replacement rollers.

Q: Can this rubber roller replace a worn plastic keel roller?

Yes, if the dimensions match your brackets and shaft. This roller is rubber, 12 inches long, 95mm in diameter and bored to 25mm. If your current plastic roller shares these key measurements, it can usually be swapped out. Confirm bracket width, shaft diameter and clearance to cross members before fitting to avoid binding.

Q: Is the concave roller suitable for use on the keel position only?

It is intended for concave keel support positions. The concave profile is shaped to cradle a keel along the centreline rather than a flat hull section. Using it on the keel position helps keep the boat tracking straight during winching. Straight or parallel rollers are normally used under flat hull pads instead.

Q: Does the black rubber mark boat hulls?

The roller is black rubber, so light marking is possible on some finishes. Black rubber can leave faint traces on light-coloured hulls where heavy pressure occurs. Many users accept this on the keel where marks are not visible. Rinsing the roller to remove grit and checking alignment can reduce scuffing on the contact area.

Suitable for use as a concave keel roller on compatible marine and boat trailers that accept a 12 inch long roller with a 95mm outside diameter and 25mm shaft or pin size. Users should confirm bracket width, shaft diameter and overall setup dimensions on their trailer before installation.