Key components of a bike
KEY COMPONENTS OF A BIKE
The Frame – The frame is one of the most important components. Some BMX frames uses Hi-Tensile steel but 4130 Chromoly or Cr-mo are stronger and lighter. Butted and/or heat treated 4130 is even better. BMX racing frames are mostly aluminium and in higher levels carbon fibre.
Forks – The same applies to the forks, look for 4130 Chromoly or Cr-mo for stronger and lighter. CNC'd sheerer tubes are even stronger and last longer as well as tapered or aluminium/carbon fibre fork legs for weight saving.
Handlebars – The bars are very similar to the forks and frame when considering the material. 4130 cr-mo is king. Heat treated and/or multi butted tubing have even better weight and strength ratio.
Headset - There are two types of headset. A headset - this is the older style with external cups found on entry level BMX bikes; Integrated - The bearings cups are integrated into the frame for greater strength while saving weight.
Brakes - Brakes are important, however every set up is different and every rider has their own preference. Some freestyle riders ride without brakes.
Front Hub - Sealed bearings offers more durability. An un-sealed front hub is fine but they do require more maintenance.
Rear hub - There are two types of rear hub; a) Regular or freewheel hubs which use screw on freewheels (anything from a 13t to a 16t) and the more reliable b) Cassette hubs which use anything from an 8t upwards and are built into the hub itself. Look for sealed bearings in these if you have some BMX experience.
Gearing - The relation between the front sprocket and the rear freewheel or cassette hub. There are many different set-ups.
Rims - The outside part of the wheel. These come in standard single wall or double wall versions. Double wall offers more strength and will last a longer than single wall types but are heavier.
Tyres - Usually wider on the front than on the rear. However some racing bikes now offer similar sized tyres on both the front and rear to offer some grip and cushioning on the back. The finer tires are faster but trickier to control.
Cranks - Cranks needs to be strong enough to match your level of riding. Look for tubular 3 piece options with splined spindles being better. Splines offer protection from cranks wearing out and coming loose.
Bottom Bracket's - There are many types of BB's. In most cases they use sealed bearings.
Pedals - There are two types of pedals; the longer lasting alloy ones and the lighter plastic pedals.
Seats - There are two types of seats now. There is the traditional railed seat or the lighter pivotal types. The pivotal seat is usually found on higher level bikes to keep the weight down. Plastic pivotal seats will again save some weight.
Stem - The bit that holds the handlebars to the forks. All stems are comparable in strength but look for CNC'd stems on the mid to Pro level bikes for weight saving.