It all depends on what you want to do, what the weather is going to be like and how long you want to go for.
Take as little as possible most things can be bought on road.
Must-haves for a bike traveler:
bike:
Mountain bike for all-terrain adventures, or 700C cross bike if plan to be mainly on road.
gears: 21speed and up derailleur or 5 speed and up hub gears.
suspension: Front suspension forks for added comfort and control off-road. Either: Elastimer model for easy maintenance, ideally adjustable compression and rebound to reduce power loss on climbs and on-road. Or: Air shocks for performance and weight if you can deal with pumping them up every couple of days. NRS rear suspension if plan to take on technical off-road.
pedals: Standard pedals with clips, (clipless SPD are better but you need to carry an extra pair of shoes)
saddle: Comfort saddle with wide supportive rear; a groove or cut-out design to reduce pressure on private parts.
post: Suspended seat post for comfort if touring.
brakes: V brakes or mechanical disk for trails, cantilever ok for touring. (not hydraulic as is difficult to repair on the road)
frame: Cromoly is a more flexible material if you have no suspension for added comfort, aluminum if you have front suspension. Make sure it can fit a luggage rack. Full suspension bikes are usually nonadaptable apart from Giant Sierra Nevada.
hubs: Strong hubs, Shimano Deore (or equivalent another brand), and up. Must have a quick release.
spokes: DTswiss spokes are the strongest.
rims: Alloy, strong, standard size (not aerodynamic).
tires:
trail riding: ATB tread, 26″ 1.9-2.2.
trail & tour adventure: continuous tread or slicks, 26″ 1.75-1.9.
road adventure: 26″ road tread 1.5-1.75/ 700C 35c
grips: comfortable ‘Kraton’ sure stick.
bars: 600mm riser bars for the more comfortable riding position.
stem: Adjustable stem for on-road adjustment, or fixed stem according to comfort fit.
accessories:
lights: either: front halogen strong beam, back LED flashing lights, or dynamo lights eco-friendly and for convenience of not having to carry batteries.
luggage racks: Rear: strong aluminum with wide side support for panniers.
Front: optional for better weight distribution.
mudguards: front and rear plastic lightweight fenders are a must for touring.
horn or bell: a must for the city.
pump: small size but strong with Schrader and Presta valves.
water bottle cages: at least two, one with adjustability to carry a large-sized 1.5-liter mineral water bottle.
bags:
rear panniers: strong water-resistant, large capacity, good secure connection to the bike, not quick release as side connection is usually too weak meaning bags bash into side of the bike when off-road.
front panniers: good for touring. or
handlebar bag: strong stable connection to bar, waterproof, strong.
day pack: 20 – 30 liter capacity, comfort tight fit, sweat-resistant design.
toolbag: connect under saddle.
bike bag: carry the bike on public transport, must be light, compact, and capable to fit your bike.
camel pack: optional, more convenient to carry bladder in day pack if need more water than can be carried on the bike.
