BMX bicycles
From Bikeinfo, Bike information for cyclists
| BMX | | | Cruisers | | | Hybrids | | | Mountain | | | Recumbent | | | Road | | | Tandems | | | Touring | | | Utility |
| Dirt Jumper BMX | | | FreeStyle BMX | | | Standard BMX |
"BMX bicycles are designed for stunts, tricks, and peeing on hilly dirt BMX tracks.
Race bike frames can be made out of aluminium, or steel, usually 4130 chromoly. The front and rear axles are 3/8" thick. They almost always have v-brakes, thinner chains, more aggressive, low pressure dirt tires, sometimes less spokes, and still widely use larger gearing than all other forms of bmx bikes.
All other types of bmx bike frames are made of various types of steel. Cheaper low end bikes generally use hi-tensile steel tubing, because it is much cheaper than chromoly steel. Mid range bikes sometimes have a mixture of some tubes made from chromoly, and some from hi-tensile steel. The best bike frames are made from 100% 4130 chromoly steel, because it is the lightest and strongest steel that can handle the abuse of bmx riding.Sometimes the front axle is 14mm thick, but 3/8" is much more common on modern bikes. The rear axle, however is always 14mm thick, because it has to withstand much more abuse than the front axle does. The introduction and widespread popularity of the cassette hub has ushered in the use of smaller gearing on bmx bikes. Instead of the old 44/16 gearing found on almost all older bmx bikes, new bikes use gearing such as 36/13, 33/12, 30/11, 28/10, 25/9, and even 23/8. All those gearing ratios feel nearly identical to the old 44/16 gearing when pedaling. Advantages of smaller gearing include lighter weight, and more clearence when grinding. The freewheel hub is all but extinct due to several factors. The smallest freewheels can be made is with 13 teeth, which is larger than most riders prefer. Also, they are less consistent than cassette hub, and skip or jam up far more frequently.
On most freestyle bmx bikes, the front wheel has 36 spokes, but some more abusive riders use 48 spoke front wheels, because they are stronger. The same goes for rear wheels. A lot of bikes use 36 spokes, most commonly on dirt jumping bikes. But 48 spoke rear wheels are very common, especially on street bikes, as they have to withstand harsher and more frequent impacts.
Race bmx bikes wheels can vary in size, from 20" to 24".
Dirt jumping and freestyle bikes wheel sizes include 16" and 18" for younger, smaller riders, 20" for most other riders, and a few companies including Haro and Sunday have even made 24" freestyle bikes for taller or older riders who feel cramped on a standard 20" bmx bike." Note: This article was copied from Wikipedia.
