Arturo, the Pan-American Highway sounds like the route for you. But don't expect a 6 lane expressway, this is one of the toughest, most hazardous and potentially dangerous journeys around.... The route takes you through some pretty dodgy places and it will be a huge challenge.
The Pan-American highway isn't a single road, it's a collection of various national highways kind of connected together. One of the major challenges: there's a section of 87 kms where there's no road at all. The Darien Gap in the south of Panama, is a stretch of rainforest with no official road. Some have crossed it on foot, bicycle,or motorbike but it's a real challenge.
Obviously you're an adventurer, but you might want to think carefully about which bits you want to tackle, and which bits (for safety's sake) you give a miss. Will you tackle this alone, and potentially risk your safety... or will you have a support crew meet you at various stages to help you repair the bike, and organise visas and cargo carnets, or be there if you get sick. You need to plan this very thoroughly. Let us know what you decide, and if you go ahead we'd love to be able to follow your journey on a worldnomads.com journal.
Phil over 8 years ago