Cuba is a cyclist's paradise, with bike lanes, bike workshops and drivers accustomed to sharing the road countrywide. Spare parts are difficult to find – you should bring important spares with you. Still, Cubans are grand masters at improvised repair and, though specific parts may not be available, something can surely be jury-rigged. Poncheros (puncture repair stalls) fix flat tires and provide air; every small town has one.
Helmets are unheard of in Cuba, except at upscale resorts, so you should bring your own. A lock is imperative, as bicycle theft is rampant. Parqueos are bicycle parking lots located wherever crowds congregate (eg markets, bus terminals, downtown etc); they cost one peso.
Throughout the country, the 1m-wide strip of road to the extreme right is reserved for bicycles, even on highways. It's illegal to ride on sidewalks and against traffic on one-way streets and you'll be ticketed if caught. Road lighting is deplorable, so avoid riding after dark (over one-third of vehicle accidents in Cuba involve bicycles); carry lights with you just in case.
Trains with coches de equipaje or bagones (baggage carriages) should take bikes for around CUC$10 per trip. These compartments are guarded, but take your panniers with you and check over the bike when you arrive at your destination. Víazul buses also take bikes.
Limited selection and high prices make buying a bike in Cuba through official channels unattractive. Better to ask around and strike a deal with an individual to buy their chivo (Cuban slang for bike) and trade it or resell it when you leave. With some earnest bargaining, you can get one for around CUC$40 – although the more you pay, the less your bones are likely to shake. Despite the obvious cost savings, bringing your own bike is still the best bet by far.
Official bike rental places are scant in Cuba, but with the private economy taking off so rapidly, this could change. You can usually procure something roadworthy for between CUC$5 per hour or CUC$20 per day. Bikes are usually included as a perk in all-inclusive resort packages, but beware of bad brakes and zero gears.