Bicycles in China
They provide a form of transportation for a majority of people in China, so much so that in major cities there are cycling side roads set aside on all major roads. Once of the nice things about many Chinese cities is that they are for the most part, very flat. No stories about having to ride uphill to and from school...
It might look scary but riding a bicycle is a great way to see China, as you can pretty much go anywhere and don't have to worry about car traffic-- just bike traffic. When you first arrive it is VERY important to watch how the locals ride their bikes before they attempt a try; although don't necessarily copy their riding style! I recommend that one be careful with parking--sometimes random parking may result in a fine. Seriously. Observe and learn. With that many bikes on the road there has to be some method to the madness.
Bicycle Rental in China
In most of the major cities there are many places that rent bikes--large repair shops as well as hotels--with prices ranging from 2 Yuan per hour to 40 Yuan per day depending on the style of bike.
Purchasing a Bicycle in China
The most popular Chinese brands are: Flying Pigeon (Feige), Phoenix (Fenghuang) and Forever (Yongjiu). You should be able to purchase a reliable Chinese bicycle for about 50 USD.
Sometimes it is BETTER TO BUY A BIKE IN CHINA rather than bring your own. You already stand out in the crowd by virtue of non being Chinese. Your foreign bike will also stand out which might make it a target to be stolen.
Bicycle Repair in China
You can try a large repair shop but there are abundant repair stalls with all the spare parts. A new inner tube should cost lest than 15 Yuan, and an inner tube and tire about 30 Yuan--all including labour.