Cycling in Cambodia is for the more adventurous traveller, but if you're an experienced cyclist you'll discover the real Cambodia. Most of Cambodia is quite flat and recently many roads have been upgraded, so road conditions have improved considerably.
Of course you'll still come across bumpy roads in the countryside, but isn't that part of the fun? Cycling in Cambodia should only be done during the dry season, from November until March, when the temperatures are not too high.
When cycling just after the end of the rainy season, the country is lush and green.