Spanish · 5 years on Samui
Spanish cycling enthusiast and eco-travel advocate on Koh Samui for 5 years. Carlos covers all bicycle and e-scooter content with a focus on sustainable exploration.
Updated: May 2026
On the Nathon ring road straight last January at 28 km/h - the Merida Big.Nine 15 in the middle front chainring and a mid-range rear sprocket - the bicycle felt composed and efficient without requiring constant effort to maintain pace. The 29-inch wheels roll fast on the ring road's tarmac sections; the Acera drivetrain maintains indexing precision at sustained effort levels. After 50 kilometres on the ring road last February, I arrived at the Chaweng shop without the drivetrain-induced fatigue that imprecise shifting causes on a long circuit. The Big.Nine 15's ring road performance is its most consistently demonstrated quality.
Approaching the 8 per cent gradient Nathon ring road climb last March on the Merida Big.Nine 15, I shifted to the small front chainring and largest rear sprocket before the gradient demanded it - the Acera indexing responding immediately to the lever movement. At the steepest section, I maintained 9 km/h at 80 rpm cadence without standing: the correct gear for the gradient. The Big.Nine 15 completed the Nathon climb without requiring dismounting at any point. For a rental bicycle, consistent hill-climbing without drama is the most practically important performance characteristic - and the Big.Nine 15 delivers it.
Riding the north coast road at Mae Nam last November on the Merida Big.Nine 15 - flat tarmac, slight tailwind, the Gulf of Thailand on my left - I sustained 25 km/h for 8 kilometres without aerobic effort. The 29-inch wheels contribute directly to flat-road speed: larger wheels require fewer rotations per kilometre and maintain momentum more easily between pedal strokes. On Samui's longest flat section - the north coast from Chaweng to Mae Nam - the Big.Nine 15 rolls faster than 27.5-inch wheel bicycles at the same effort level. The rolling efficiency advantage is measurable and consistent.
At the Na Muang waterfall trail last February - compacted laterite surface, embedded rocks, two gentle water crossings - the Merida Big.Nine 15's Suntour XCM fork absorbed the surface within its 100mm travel without bottoming out on any impact. The 29-inch tyres maintained forward momentum through the rocky lower section where smaller wheels would deflect. The Big.Nine 15 is competent on the Na Muang trail but not as composed as the Trek Marlin 5's RockShox fork on the same surface. The difference is real; it is not a deal-breaker for the trail section's difficulty level.
Five years of riding the Merida Big.Nine 15 across every Samui cycling surface has produced a consistent performance profile: efficient and composed on ring road tarmac, capable on the Na Muang trail in dry conditions, fast on the north coast flat, and reliably hillclimbing with Acera gearing on the Nathon climb. The Big.Nine 15 does not match the Trek Marlin 5 on technical trail sections, but on Samui's primary cycling routes - ring road, coastal roads, and the Na Muang trail addition - it performs at a level that justifies its position as the best value bicycle in the rental fleet.
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First-hand road and trail guides written by our local team - where to go, when to ride, and what to watch out for.
