Street Cowboy
12-01-2004, 06:40 AM
Article from BMX-Zone.com, http://www.bmx-zone.com/en-article-id-102.html
There are many makes and models of bikes costing any ware from $100 to $2000. when buy a bike you are paying for the attention to detail and quality of materials used.
A cheap $100 bike will be made of low grade steel and have cheap components. The bike will most likely have 9mm axels on the wheels, forged steel 1 piece cranks and unsealed bearings. Flatland bikes and racing bikes are often made of materials not mentioned here such as titanium and aluminum. These bikes are also not as strong as street bikes and are built smaller and lighter. Street/Vert bikes are the most popular because they can be used for just about anything. However like anything its always best to have the right tools for the job. Flatland bikes are built the way they are, so as to make the types of tricks you do on them easier. A flatland bike would not make a good dirt jumper and could break under the stresses associated with that type of riding. In contrast a dirt bike would not be good for flatland because of its size and weight distrobution. Before you get a BMX figure out what type of biking interests you the most! Most of this will be in regards to street. Some of what I say applies to flatland dirt and racing. street bikes are by far the most versitile
High end expensive bike frames (for street) are made of 4130 chromoly steel. 4130 is an alloy steel that has an extremely high resistance to breaking, bending and is extremely weldable. The strength of the metal can be increased with various treatments such as annealing or heat treating. Middle range bikes are often made from either a combination of 4130 chromoly steel and high-tensile steel or some such mesh of comparable metals. High tensile steel is cheaper and not as strong as 4130 chromoly steel. It also has more flex in it so in instances where it is used in the rear triangle you loose out on acceleration. The combinations usually come this way, with the top tube and bottom tube made of 4130 and the rear triangle out of high-tensile. If you are planning on getting serious into street riding you should think of getting a bike that is made of 100% 4130. higher end bikes will also have internal machining to maximize strength and minimize weight and are often hand welded. The less you pay for a bike or bike frame the less work they put into it. The lowest end bikes are made by machines in mass production facilities. Less attention is paid to the finer aspects of the makeup.
Your fork is as important as your frame. A good fork will be strong enough to take lots of bad landings and still hold your wheel true. The better forks are made of high grade 4130 chromoly often heat treated. The tubes are fluted on the inside to maximize strength. The tubes are often double or triple butted . meaning the ends are folded in on them selves to again maximize strength. (forks made of titanium and aluminum are for racing and flatland) and last have well crafted and strong dropouts. The cheaper forks come made of cheaper materials and have less of the extras added to their manufacturing. Things like fluting the tubes or precision cutting the dropouts get left out.
Your dropouts and axles are important part of your bike. Ideally both your fork and frame will have 14mm dropouts, low end bikes will have 9mm. Most middle level and high end bikes come with 14mm dropouts. Its important to check first though. The other measurement on your dropouts is the width of the metal. This is often around 5 or 6 mm, if they state its double butted or triple butted then that’s a plus. The difference between a solid 9mm axle and a hollow 14mm axle is surprising. 9mm are prone to bending after big jumps and grinding. A hollow tube has more strength and can sustain the weight and pressure of your bike much better. Having a good hub and axle is a good idea. The better your hubs perform the better your bike will roll. Sealed bearings will ensure that your wheels roll longer by preventing dirt from grinding away at the bearings. Its important to keep your wheels tight . the slightest wiggle should be tightened. Or you can do allot of damage to your hub in the long run.
Your hub is connected to your spokes and your spokes are connected to your rims. There are all sorts of rims. Depending on how you have your bike set up you might prefer different choices. I’m a fan of strong chromed rims . chrome (not 4130 chromoly) is the best surface for breaking. Black and raw metal rims don’t have the stopping power. There are all types of rims . ones that will take allot of pounding and those that wont. The more you spend on you rim holds true to a cretin extent higher end rims will have internal metal and double or triple walled rims . this is the same idea as triple or double butting a tube . folding the metal over makes the strength higher. avoid black or raw metal rims at all costs
Freewheels free coasters and fixed gears. The freewheel is the most popular type of rear gear. The freewheel will engage when you pedle forward and allow you to pedal backwards freely however if your bike is going back wards your crank will rotate backwards. The free coaster, used mainly for flatland will allow you to move your bike backwards without your crank moving. This set up is slightly more heavy. Finally fixed gears are when the back gear is fixed to the back wheel. The wheel moves in the direction as the crank regardless of the direction. This is rarely used in BMX. For gearing ratios read on a cassette is when the cog and hub are one. Intead of screwing on a free wheel the cog is more directly attached. This allows for smaller gearing
Chain wheel or sprocket.. the toothed cog that is attached to your crank that holeds your chain. These come in many shapes and forms (almost all roundish). Some with guards some with holes cut into them. All different. No particular design is better than the next i like the malties cross.. some are made of lighter materials that are prone to bending .. some are heavy and stiff. othere are a bit of both or non of the above. A smaller chain wheel will lower your gearing ratio and top speed but also make it harder to bend or get damaged
Cranks on almost all low end bikes you will find a 1 piece crank. These are made of heavy forged steel which is prone to bending and snapping. One piece cranks can also be hard on your knees when it comes to bad landings. A 3 piece crank is good to have. Although not all are equal they make a big difference on the predictability of your pedals and the efficiency of your bike. The three parts to a three piece crank are the spindle and two crank arms. (there are other pieces like the bearing cups, spacers, bolts etc) The crank fits into your bottom bracket. The two main sizes are euro bb and American bb. Euro is smaller and has threads so you screw your bearing cups into place and American are bigger and you bash them into place. I am partial towards the euro but to each their own.
The ideal street set up would be a bike with two chromed wheels 48 spokes on the back 36 on the font and good hubs with 14mm hollow axels fully inflated tires with 100+ psi . The frame and fork will be made of heat treated 4130 chromoly. The bike will have a hollow spindle 3 piece crank. All the bearings on the bike will be sealed. The breaks will have slick pre-stretched cables and breaks on the seat stay tube for chain clearance. The seat will have a strong high impact material like Kevlar and will be attached to the seat post with a two bolt system. The stem will be a front loading stem for easy access. your chain is waxed and everything is properly lubed and greased.
remember i wrote this ages ago so if im wrong. let me know.
ok here is my little thing on titanium enjoy
<hr style="width: 100%; font-family: helvetica; height: 2px;"/>
TITANIUM
Titanium comes in many different shapes and forms. Usually alloyed with aluminium, magnesium, iron and other metals it is a strong metal that is difficult to work with.
Pure titanium is not as strong as steel but 45% lighter and although 60% heavier than aluminium, it has twice the strength and a pearly white sheen that has a higher diffusion rate than diamonds.. Pure titanium has a tensile strength of about 234 mpa and costs about $100 for a pound of pure powder. (one of the reasons those sweet bikes cost so much) it is the 22nd element on the periodic table and is extremely resistant to corrosion as well as very resilient to fatigue
The two most common applications of titanium are Ti 6-4 (6% Aluminum, 4% Vanadium, 90% Titanium), and Ti 3-2.5 (3% Aluminum, 2.5% Vanadium, and 94.5% Titanium). Ti 3-2.5 was created specifically to make high strength tubing, while T- 6-4 was created for structural components in aircrafts. Welding titanium makes it susceptible to haz (heat affected zone) which can lead to failure. So great care has to be taken when working with the metal. I should also note that it wasn’t until recently that the ability for people to manufacture titanium tubing came along (tubes where made from welded up sheets). This and its cost are the reasons why it is still fairly new to the world of bikes. The world of titanium frames is just opening up. It might seem like a trend but for many types of bikes it should end up as more than just that. Welding Ti requires extensive gas chambers and is an expensive proccess.
<hr style="width: 100%; font-family: helvetica; height: 2px;"/>
ALUMINUM
Aluminum was first isolated in 1825, became available to the public in the late 19th century/early 20th. It is the most abundant metallic element in Earth's crust. It is the 13th element on out periodic table and has a melting point of 660.25°c. Aluminum is now the second most used metal (second to iron). Aluminum has many key propertys for making it a great material to make bikes with propertys that inculde weight reduction, corrosion resistance, machinability, aluminum does not bend well thus making it rigid. It has a high load-carrying capacity and fatigue strength When over stressed it will often crack instead of bend. Two common number associated. Aluminum is most often alloyed with copper magnisium and silicon with aluminum are 7075 and 6061 where 6061 is better for welding and frame design 7075 makes for better machineability. And is more often used in things like pedals and stems. There are hundreds of differant grades of aluminum its easy to get lost. Even within 6061 and 7075 there are differences. Aluminum is great for racing and flatland bikes where having a rigid light bike is important.. Aluminum is now cheaper to weld then steel so more aluminum bikes will appear on the market in years to come
There are many makes and models of bikes costing any ware from $100 to $2000. when buy a bike you are paying for the attention to detail and quality of materials used.
A cheap $100 bike will be made of low grade steel and have cheap components. The bike will most likely have 9mm axels on the wheels, forged steel 1 piece cranks and unsealed bearings. Flatland bikes and racing bikes are often made of materials not mentioned here such as titanium and aluminum. These bikes are also not as strong as street bikes and are built smaller and lighter. Street/Vert bikes are the most popular because they can be used for just about anything. However like anything its always best to have the right tools for the job. Flatland bikes are built the way they are, so as to make the types of tricks you do on them easier. A flatland bike would not make a good dirt jumper and could break under the stresses associated with that type of riding. In contrast a dirt bike would not be good for flatland because of its size and weight distrobution. Before you get a BMX figure out what type of biking interests you the most! Most of this will be in regards to street. Some of what I say applies to flatland dirt and racing. street bikes are by far the most versitile
High end expensive bike frames (for street) are made of 4130 chromoly steel. 4130 is an alloy steel that has an extremely high resistance to breaking, bending and is extremely weldable. The strength of the metal can be increased with various treatments such as annealing or heat treating. Middle range bikes are often made from either a combination of 4130 chromoly steel and high-tensile steel or some such mesh of comparable metals. High tensile steel is cheaper and not as strong as 4130 chromoly steel. It also has more flex in it so in instances where it is used in the rear triangle you loose out on acceleration. The combinations usually come this way, with the top tube and bottom tube made of 4130 and the rear triangle out of high-tensile. If you are planning on getting serious into street riding you should think of getting a bike that is made of 100% 4130. higher end bikes will also have internal machining to maximize strength and minimize weight and are often hand welded. The less you pay for a bike or bike frame the less work they put into it. The lowest end bikes are made by machines in mass production facilities. Less attention is paid to the finer aspects of the makeup.
Your fork is as important as your frame. A good fork will be strong enough to take lots of bad landings and still hold your wheel true. The better forks are made of high grade 4130 chromoly often heat treated. The tubes are fluted on the inside to maximize strength. The tubes are often double or triple butted . meaning the ends are folded in on them selves to again maximize strength. (forks made of titanium and aluminum are for racing and flatland) and last have well crafted and strong dropouts. The cheaper forks come made of cheaper materials and have less of the extras added to their manufacturing. Things like fluting the tubes or precision cutting the dropouts get left out.
Your dropouts and axles are important part of your bike. Ideally both your fork and frame will have 14mm dropouts, low end bikes will have 9mm. Most middle level and high end bikes come with 14mm dropouts. Its important to check first though. The other measurement on your dropouts is the width of the metal. This is often around 5 or 6 mm, if they state its double butted or triple butted then that’s a plus. The difference between a solid 9mm axle and a hollow 14mm axle is surprising. 9mm are prone to bending after big jumps and grinding. A hollow tube has more strength and can sustain the weight and pressure of your bike much better. Having a good hub and axle is a good idea. The better your hubs perform the better your bike will roll. Sealed bearings will ensure that your wheels roll longer by preventing dirt from grinding away at the bearings. Its important to keep your wheels tight . the slightest wiggle should be tightened. Or you can do allot of damage to your hub in the long run.
Your hub is connected to your spokes and your spokes are connected to your rims. There are all sorts of rims. Depending on how you have your bike set up you might prefer different choices. I’m a fan of strong chromed rims . chrome (not 4130 chromoly) is the best surface for breaking. Black and raw metal rims don’t have the stopping power. There are all types of rims . ones that will take allot of pounding and those that wont. The more you spend on you rim holds true to a cretin extent higher end rims will have internal metal and double or triple walled rims . this is the same idea as triple or double butting a tube . folding the metal over makes the strength higher. avoid black or raw metal rims at all costs
Freewheels free coasters and fixed gears. The freewheel is the most popular type of rear gear. The freewheel will engage when you pedle forward and allow you to pedal backwards freely however if your bike is going back wards your crank will rotate backwards. The free coaster, used mainly for flatland will allow you to move your bike backwards without your crank moving. This set up is slightly more heavy. Finally fixed gears are when the back gear is fixed to the back wheel. The wheel moves in the direction as the crank regardless of the direction. This is rarely used in BMX. For gearing ratios read on a cassette is when the cog and hub are one. Intead of screwing on a free wheel the cog is more directly attached. This allows for smaller gearing
Chain wheel or sprocket.. the toothed cog that is attached to your crank that holeds your chain. These come in many shapes and forms (almost all roundish). Some with guards some with holes cut into them. All different. No particular design is better than the next i like the malties cross.. some are made of lighter materials that are prone to bending .. some are heavy and stiff. othere are a bit of both or non of the above. A smaller chain wheel will lower your gearing ratio and top speed but also make it harder to bend or get damaged
Cranks on almost all low end bikes you will find a 1 piece crank. These are made of heavy forged steel which is prone to bending and snapping. One piece cranks can also be hard on your knees when it comes to bad landings. A 3 piece crank is good to have. Although not all are equal they make a big difference on the predictability of your pedals and the efficiency of your bike. The three parts to a three piece crank are the spindle and two crank arms. (there are other pieces like the bearing cups, spacers, bolts etc) The crank fits into your bottom bracket. The two main sizes are euro bb and American bb. Euro is smaller and has threads so you screw your bearing cups into place and American are bigger and you bash them into place. I am partial towards the euro but to each their own.
The ideal street set up would be a bike with two chromed wheels 48 spokes on the back 36 on the font and good hubs with 14mm hollow axels fully inflated tires with 100+ psi . The frame and fork will be made of heat treated 4130 chromoly. The bike will have a hollow spindle 3 piece crank. All the bearings on the bike will be sealed. The breaks will have slick pre-stretched cables and breaks on the seat stay tube for chain clearance. The seat will have a strong high impact material like Kevlar and will be attached to the seat post with a two bolt system. The stem will be a front loading stem for easy access. your chain is waxed and everything is properly lubed and greased.
remember i wrote this ages ago so if im wrong. let me know.
ok here is my little thing on titanium enjoy
<hr style="width: 100%; font-family: helvetica; height: 2px;"/>
TITANIUM
Titanium comes in many different shapes and forms. Usually alloyed with aluminium, magnesium, iron and other metals it is a strong metal that is difficult to work with.
Pure titanium is not as strong as steel but 45% lighter and although 60% heavier than aluminium, it has twice the strength and a pearly white sheen that has a higher diffusion rate than diamonds.. Pure titanium has a tensile strength of about 234 mpa and costs about $100 for a pound of pure powder. (one of the reasons those sweet bikes cost so much) it is the 22nd element on the periodic table and is extremely resistant to corrosion as well as very resilient to fatigue
The two most common applications of titanium are Ti 6-4 (6% Aluminum, 4% Vanadium, 90% Titanium), and Ti 3-2.5 (3% Aluminum, 2.5% Vanadium, and 94.5% Titanium). Ti 3-2.5 was created specifically to make high strength tubing, while T- 6-4 was created for structural components in aircrafts. Welding titanium makes it susceptible to haz (heat affected zone) which can lead to failure. So great care has to be taken when working with the metal. I should also note that it wasn’t until recently that the ability for people to manufacture titanium tubing came along (tubes where made from welded up sheets). This and its cost are the reasons why it is still fairly new to the world of bikes. The world of titanium frames is just opening up. It might seem like a trend but for many types of bikes it should end up as more than just that. Welding Ti requires extensive gas chambers and is an expensive proccess.
<hr style="width: 100%; font-family: helvetica; height: 2px;"/>
ALUMINUM
Aluminum was first isolated in 1825, became available to the public in the late 19th century/early 20th. It is the most abundant metallic element in Earth's crust. It is the 13th element on out periodic table and has a melting point of 660.25°c. Aluminum is now the second most used metal (second to iron). Aluminum has many key propertys for making it a great material to make bikes with propertys that inculde weight reduction, corrosion resistance, machinability, aluminum does not bend well thus making it rigid. It has a high load-carrying capacity and fatigue strength When over stressed it will often crack instead of bend. Two common number associated. Aluminum is most often alloyed with copper magnisium and silicon with aluminum are 7075 and 6061 where 6061 is better for welding and frame design 7075 makes for better machineability. And is more often used in things like pedals and stems. There are hundreds of differant grades of aluminum its easy to get lost. Even within 6061 and 7075 there are differences. Aluminum is great for racing and flatland bikes where having a rigid light bike is important.. Aluminum is now cheaper to weld then steel so more aluminum bikes will appear on the market in years to come