BMX’s are all about skill and speed, combining the two to get the very best out of the bike as you possibly can. You need to be skillful, and you need to be going at 100% speed all the time. Skill is a natural ability, and it will continue to grow as you practice, you cannot buy it. Speed on the other hand is a mixture of your ability and power as well as the best bike. So, for example, if you have the lightest BMX, then you will have the edge over others when it comes to speed!
There are two main disadvantages of lightest BMX bikes than heavier ones. The first is pretty obvious; price. To make an extremely light bike, you need the very best of materials, and this costs a lot of extra money. The other main disadvantage is the lighter the bike is, usually the easier it will fracture and/or break. This is not good at all, if you are paying top money for your bike.
So, in my opinion, you should only be buying the lightest BMX bikes if you compete, or take videos etc. and you need to be at the very top of your game. If not, then just save yourself some money and get a regular BMX. Even still, i have included a few lightest BMX’s and top of the range BMX’s below: