P.O. Box 5
Afton, NY 13730
607.639.8200

     Bicycle riding has been greatly affected by continuous advancements in the chemistry of different materials.  This ranges from metals to greases to plastics.  All creating their own niche in putting together a well maintained bike.  Many different metals have been used to try and create the perfect balance of qualities in a frame, strength, weight, and affordability.       Throughout the years many people and companies have been able to make a decent combination, but often with a compromise of one of the desired end products.  Just recently, within the past 20 years, bicycles have begun to be made with specially treated, exotic types of metals.  These processes are used to try to achieve the lightest possible metals, while maintaining a high strength.  In lower end bicycles, simple steel is mainly used.  This makes for a very cheap bike, while holding a decent strength for easy riding.  Many mountain and off road bicycles are made using a usually expensive aluminum alloy or treated aluminum.  Many freestyle and BMX bikes are made out of a stronger alloy of steel, 4130 chromoly.  These metals are the most commonly used for that specific style of riding.  With each style comes a different way of use and a different requirement for the metal to fulfill (source 3).  

     For many years, 4130 chromoly steel has been accepted as the best steel alloy for the special abuses made by a BMX racer or freestyle rider.  It is stronger than generic steel, and can be made into thinner tubing, while reducing weight and maintaining its overall strength.  Because of these reliable traits for 4130 chromoly steel, it is not only used in the bicycle industry.  Other groups that use the metal are the military and the airline industry, for select parts.  As with all steels, 4130 chromoly is capable of being welded.  The 30 in 4130 represents a value of 0.30 percent carbon content. It is a general cut-off value for weld ability. Alloys with more than 0.30 percent carbon can not weld as easily.  The chromoly in 4130 chromoly steel is the combination of two prefixes.  The ?chro? is from the use of chromium, and the ?moly? stands for molybdenum in the steel.  While 4130 chromoly steel is the most used, there are other steels.  A stronger one is 4140 chromoly steel.  A newer welder will say that they could weld 4140 chromoly steel as well as 4130 chromoly steel.  In actuality anything above .30 carbon content is extremely hard to weld without the weld cracking or having hidden occlusions or inclusions in side the weld.  4130 steel is available as billet, bar, rod, forgings, sheets, plate, tubing, and castings. It is used to make automotive connecting rods, engine mounting lugs, shafts, fittings, bushings, gears, bolts, axles, gas cylinders, airframe components, hydraulic lines, and nitrided machinery parts (source 4).

    Aluminum is another highly used metal in the bicycle industry.  Many mountain and road bikes utilize aluminum and various aluminum alloys to create a lighter, stiffer ride than steel alloys.  The most desired trait that aluminum almost always carries is that it is extremely light weight.  Certain aluminum alloys even approach the strength of steel.  Aluminum can be easily modified by the addition of alloys to make a final metal that is even more resilient, conductive, or malleable than aluminum alone.  Aluminum carries the highest strength to weight ratio of any known metal.  Another delightful trait of aluminum is that it does not corrode.  The formation of a microscopic film of aluminum oxide on the surface of the metal protects it against the corrosive influences of water, salt and other influences. Aluminum can also be finished with a variety of coatings and finishes, such as paint, powder coat, lacquer, porcelain or organic coatings, which can be anodized to bond to the metal.  The most common ways of finishing aluminum for bicycle parts are polishing, anodizing, or powder coating.  Some aluminum alloys are valued for there ability to be bent and still retain their strength, such as for a brake lever, seat posts, handle bars, seat stays, chain stays, various size bicycle rims, and forks.  For lighter weight BMX racing riders, aluminum bars, forks, and even frames can be used.  This is because racing does not abuse these parts as much as a freestyle BMX would (source 2).

    A new type of metal is quickly emerging amongst the freestyle BMX industry that has been amongst mountain bike, road bike, and racing industries for years.  This metal would happen to be Titanium.  Titanium has recently come into more freestyle use as a trend.  The goal is to shave weight from your bike whenever possible.  This has been done with the use of titanium spoke, titanium crank spindles, titanium hub axles, titanium bolts, titanium cassette hub cogs, titanium pegs, and titanium seat post clamps.  Many of these parts have been used by racers for the past ten years, but freestyle riders are beginning to realize that they can utilize lighter parts than steels, and stronger than aluminums.  While for many people the introduction of titanium components has meant a lighter bike, it means also a more fragile bike.  This is the one major downside to titanium.  While it does have quite a high strength, titanium is very brittle.  Because of this different alloys have been created to try to solve this fragility problem.  A commonly used titanium alloy is 6al 4v titanium, which gives a higher strength than generic titanium.  The ?6al? stands for .6 percent aluminum, while ?4v? stands for .4 percent vanadium.  Another highly valued trait of titanium is that, like aluminum and its alloys, it does not corrode.  Another difference by the introduction of titanium into usually non-titanium parts is how the metal reacts to different stresses.  One of the differences I have personally noted is that titanium pegs grind slower on steel than heat treated steel pegs.  This is because the titanium atoms are not as tightly packed as the steel after it is heat treated (source 1).

A newer style metal that has been used in freestyle BMX frames is Reynolds 853 steel.  This is a specially treated steel alloy that actually gains strength as it is welded.  Reynolds 853 is air treated to increase overall integrity within the metal.  The amount of psi that a tube of Reynolds 853 steel can handle is about 190,000 lbs.  Because of this double butting has become very popular with this style of tubing.  This is when the ends of the tube are thicker than in the middle, reducing weight while still maintaining a great amount of strength.  This also maintains joint structural integrity as have the ends thicker keeps the weld rigid.  The major downside to the use of this style of steel is that it is very expensive.  This usually means a limited amount of frames are made using this metal to keep the affordability up (source 18).         

Anodizing is a common way of finishing aluminum components.  By performing this process onto a part, it gains a certain amount of protection from the elements and a very clean looking finish.  The anodizing process occurs when a piece of metal is set into a certain solution, depending on the color.  The liquid is then laced with an electrical current, which fuses atoms of color to the metal.  As the current flows though the solution longer, the coating grows integrally with the base metal and is corrosion and wear resistant and machinable.  The thickness can be very closely controlled and be applied to a wide variety of parts to suit applications from many industries.    This process is usually done usually stems, brake levers, sprockets, seat post clamps, brake bodies, hub bodies, hub guards, some crank arms, pedals, some seat posts, bar ends, and various expensive rims (source 8).

Another process that is commonly used in the bicycle industry is heat treating.  By doing this to metals the atoms within the metal become tightly packed because of the way heat treating occurs.  What happens in heat treating something is the metal is heated up until it is red hot, then it is quickly cooled, usually in cool water.  What this does and how it strengthens the metal, is that when the metal is heated up to redness, the molecules within it are excited and moving around quite a bit.  By cooling the metal quickly you kind of catch the molecules off guard, and they solidify even more tightly packed than before.  Since they can move less this increases the overall strength of the metal being heat treated (source 14).

A different finishing process, which is not used so much anymore in frame finishing, is chroming.  This of course relates to many other industries where a shiny, mirror like coating is needed.  In most freestyle BMX uses, chroming is limited to the back rim.  This is because chrome has been the most dependable, and it is also the ultimate braking surface.  The process of chroming is not simple by any means and does take time.  The first step is to completely remove all of the grease, brake dust, and any lube or dirt.  Then the material is now dipped in a specially developed solution that will remove all of the paint or powder coating that it may have without harming the surface at all.  The quality of the end result begins with this step.  The object starts to get hand ground with 80 grit sand paper to remove any lettering or emblems.  The object is then buffed to a complete shine and checked for any imperfections before going to the plating department.  After being thoroughly cleaned in an aluminum pretreatment system, the object makes its way through the plating line until they reach a copper tank.  Here each product gets an initial thick coat of copper to provide an excellent deep shine and superior corrosion resistance.  Now that the product is copper plated, it is checked and repaired of any imperfections that it may have.  Then it is completely buffed to a brilliant shine.  At this point the object will pass inspection and move on to the nickel plating tanks.  Nickel is applied to increase the surface leveling and the brightness of the product.  The object now enters the last stage of the plating process. The chrome solution we use gives the end product that beautiful deep shine that we all look for (source 10).

    Unlike other methods of metal forming, forging never compromises the integrity of the final product.  The forging process retains the intrinsic strength in the grain of the original piece of metal.  There are many different forms of forging, each having a different affect on the end product.  Some bicycle parts are made by forging.  A few of them would be stems, pedals, crank arms, seat rails, sprockets, bar ends, and front and rear hub shells.  By doing this a quality product can be made relatively cheap.  The down side is that in forging, a weak spot can be created in the metal (source 12).  

    Another process used to change blocks of metal into usable bicycle parts, is CNC machining.  This is done by a special CNC machine, which you insert a block of metal into larger than the end product that you desire.  You then program the design and specifications you want into the machine, and it begins to slowly but carefully shave away at the metal, leaving an exact copy of the design.  Since this is done from a solid block of metal, there are no weak points in the metal it self.  This is because solid metal is free from impurities.

    A few of the benefits of a heavy bike are tough to enjoy.  If the bike is heavy it feels sluggish and bulky.  This makes it much harder to control and ?throw around.?  The cause of a heavy bike is usually being built with heavy parts.  Some people feel it is necessary to build a bike with heavy parts to obtain more strength than is usually needed.  These people are mostly unsmooth, proving that they need heavy duty parts because they cannot handle themselves.  They utilize overtly heavy rims, chains, sprockets, axles, cranks, and even frames.   The only advantage to this type of riding and building your bike in this manner is that it will not break, because it is a tank.  Many people have begun to realize in the past few years that having a tank is not needed all the time, sometimes not at all.

    The benefits of a lighter bike are much easier to take advantage of.  The bike responds faster and is much easier to maneuver.  This I because there is not so much mass to the bike and you have more control over it.  This has become a current trend in freestyle BMX, sometimes people have been making to much of a compromise in the build of their bikes.  Some people sacrifice to much strength, to save but a few ounces.  This is pointless because it costs money to lighten the bike in the first place.  Once you spend this money you may save the weight you want, but the downside is that since it is lighter, there is probably some metal skimped somewhere, creating a weak spot.  Now if this breaks at the point used to save weight, your investment has hit a wall, and you cannot ride the broken part anymore (source 16).  

    In many ways chemistry has come to help and improve all sorts of problems in the different bicycle industries.  It has helped to create new designs, new metals, new finishes, and new ways of getting things done.  Some of these things have been a wonderful and welcome addition to the bicycle riders.  No matter which from of riding, road biking, mountain biking, BMX racing, and freestyle BMX, all have been affected and helped out in some way by the use of chemistry.  Many things have changed and evolved to a different level than they once were in, say, the 1980?s, just by changing a thing or two.