With the increasing price of fuel and the problems of locating accessible (and cheap) parking, many commuters are considering buying a foldable bike. Folding bicycles are easy to use - you don't need a license or vehicle registration and there's usually a minimum of regulations (but even if you don't have to, ALWAYS wear a cycle helmet - most cyclist deaths are the result of head injuries.) Foldable bikes are great in city congestion and you can stash them easily at home or work. You can also take them with you on public transport.But not all foldable bikes are created equal. Foldable bike design is a compromise between strength and lightness and often that can cause problems. In addition, the increase in popularity of foldable bicycles has resulted in some manufacturers making cheaper models so they can take advantage of the trend, but their corner-cutting measures can seriously affect your cycling pleasure - and your safety.Here are 5 things to be aware of when shopping for a folding bike1: Is it well engineered? Foldable bikes have to fold so check that hinge mechanisms are sturdy and well manufactured. Bad hinges can make the bike flex, or can even break. Check the steering post, too, for build quality and rigidity.2: Is it solid? Expensive bicycles use light-weight alloys to keep the weight down but less expensive bicycles have steel frames so manufacturers look for opportunities to keep the bicycle light. Check that they haven't cut corners in construction. The frame of a well-built bike should be rigid.3: Are the fittings good quality? Manufacturers often buy-in foldable bicycle components like gears, brakes and wheels. Check that these components are well made and, preferably, by a well-known parts manufacturer.4: Is the gearing right for you? Most folding bikes come with a good set of gears but check that the range suits you. There's nothing worse than trying to ride a bicycle that's either too high- or too low-geared.5: Is it big enough? Folding bicycle manufacturers keep weight down by using smaller components. That's fine if you have a small build but taller people can be at a disadvantage. Check that the seat post can be raised enough so that your leg is almost straight when the pedal is down. Similarly, can the handlebars be adjusted to the point where you have a good riding position.So there are five important things to be aware of when buying your foldable bike. Before you buy, spend some time researching the foldable bicycle you want to purchase - the major manufacturers all have web sites. Check out a similar model at your local bike shop, or visit online bike discussions. Be cautious with really cheap bikes - they are often built to a price, not a standard, and are frequently of poorer quality. If you're purchasing on the Internet, don't buy on impulse and buy your bicycle from a vendor with a good reputation. If you do your research you'll have years of fun cycling to look forward to.