When the ground stops cooperating, the RCG-4 is the one to reach for. Silca call it the ultimate off-grid tyre for sloppy mud, sand and loose rock, and it sits at the aggressive end of the Protocol gravel range - the tyre for gravel that has quietly turned into singletrack, OHV road or off-camber loose rock.

The tread runs fewer but larger knobs than the RCG-3, spaced widely on purpose. That spacing is what stops mud and loam caking between the lugs, so the tyre keeps shedding debris instead of packing solid and turning into a slick. Those wider, taller knobs also put more rubber between the casing and whatever you are riding over.

Protection is the most comprehensive in the range: SealSkin runs bead to bead, with an extra sidewall protection layer for genuinely severe conditions. Underneath it is the same Pulsar compound, 120 TPI Race Casing and CarbonBead BeadLock as the rest of the line-up, so it still rolls better than the tread pattern suggests. Pick this one for winter gravel, mud and adventure riding where grip decides everything.

Features

• The most aggressive tread and the most protected tyre in the Protocol gravel range
• Widely spaced, taller lugs that shed mud and loam rather than caking up
• Fewer but larger knobs than the RCG-3 for grip in sloppy, loose conditions
• SealSkin puncture protection bead to bead, plus an added sidewall protection layer
• Pulsar compound holds rolling efficiency, grip and durability in balance
• Race Casing developed around the pressures used on modern wide rims
• CarbonBead BeadLock carbon fibre bead for dimensional stability
• Tubeless ready from the bead outwards

Specification

• Sizes: 700 x 45c, 700 x 50c, 700 x 55c
• ETRTO: 45-622, 50-622, 55-622
• Weight: 545g (45mm), 620g (50mm), 650g (55mm)
• Casing: Race Casing, 120 TPI
• Compound: Pulsar
• Puncture protection: SealSkin, bead to bead, plus sidewall protection layer
• Bead: CarbonBead BeadLock
• Tubeless: Tubeless ready
• Minimum sealant: 90ml (45mm), 100ml (50mm and 55mm)
• Colour: Black