Bicycles with an aluminum frame are among the most common on the modern market. This is due to the lightness of the material in combination with low cost. If steel has a specific gravity of 7.8 grams per cubic centimeter, then for aluminum this figure is about 2.7 grams. By thickening the walls, this material also beats iron because the minimum parameter is 0.8 mm, while the product will weigh less than a steel frame 0.4 mm thick. Reliability is further enhanced by the absence of welds. In addition, aluminum frames can be made in various configurations. Consider their features, advantages and disadvantages.
Description
Bicycles with an aluminum frame, due to their low weight, gain speed faster, it is easier to climb lifts on them. For the same reason, the bike stops faster after the rider stops pedaling. Aluminum in its pure form is not used, this material means its alloy with zinc, manganese, nickel, copper or magnesium.
On such bicycles it is more difficult to enter sharp turns, since they are stiffer than steel counterparts and can not bend so well. Due to the rigidity of the frame, energy from the efforts of the cyclist is transmitted to the wheels with less loss. Such subtleties play a role for professionals, for amateurs this is not a critical indicator. A stiffer and less comfortable ride becomes noticeable. Bicycles with an aluminum frame practically do not damp the vibrations transmitted to the saddle and handlebar on uneven surfaces and bumps. Such a bike requires a good cushioning unit and a comfortable saddle. This will allow part of the strikes to be leveled, which will favorably affect the movement.
pros
Let's start with the advantages of the product in question. These include:
- Light weight to improve speed and acceleration.
- Maximum resistance to corrosion processes.
- High driving performance even when climbing.
Minuses
Bicycles with an aluminum frame have a number of disadvantages, namely:
- High rigidity, which is especially felt on models without a shock absorber.
- Fast loss of reel. Due to the low weight, the bike stops faster than the counterpart with a steel frame, after the cyclist stops pedaling.
- A small working resource during active use. After a few years, cracks may appear. Manufacturers give a guarantee of 5 to 10 years, but after this period it is recommended to lubricate the part to check for possible deformations.
- If it falls on an aluminum frame, there is a higher chance of dents.
- Poor maintainability. Welding such a part is very problematic, it is better to purchase a new one.
- Pretty high price.
Folding bikes with aluminum frame
Below we list several popular brands of this type and name their brief characteristics:
- The expensive city bike Strida SX has an original exterior. It folds to the size of a compact trolley that can be transported on its own. The steering wheel can also be transformed. The pluses of the bike include the fact that the cables and wires are hidden in the cavity of the frame, it is easy to assemble, there is a trunk, disc brakes. With good maneuverability, the device weighs only 11.6 kg. Among the minuses - low payload, narrow wheels, poor depreciation.
- Smart 20. Stylish urban bike, considered one of the best in its price category. Can be exploited by women without any problems. Among the advantages - a solid frame, a convenient transformation mechanism, the presence of reflectors and other accessories. The disadvantages include the lack of a hand brake and the quality of the centering of the wings.
- Bicycle "Stealth". The aluminum frame of the Pilot-710 model does not interfere with the softness of the ride. Transport picks up speed well, has a restrained design, in the folded position it is placed in the luggage compartment of any car, it is equipped with a trunk and chain protection as standard. The disadvantages are the presence of a wide steering wheel and an uncomfortable fit for tall people. The purpose of the modification is city trips.
Kids bikes with aluminum frame
The following is a brief description of some children's and teenage models:
- Mars. This bike is designed for children from 3 years. Additional polyurethane wheels are included. The frame and fork are made of aluminum alloy, there is a steering wheel height adjustment. The diameter of the wheels is 12 inches, the mass of the model is 4.5 kg.
- Forward Timba One of the best folding bikes with aluminum frame for children 6-9 years old. It has a beautiful design, affordable price, chain protection and removable safety wheels. The disadvantages include a decent weight (almost 14 kg), as well as the need to adjust some moving parts.
- Shulz Max. These aluminum-framed kids bikes are mid-priced. The mass of the bike is 14.3 kg. It is aimed at adolescents 12-16 years old, has a load capacity of up to 110 kg. The advantages of the model are the convenience of assembly / disassembly, a good set of speed, equipment with 20-inch wheels and quality. Among the minuses - incorrect factory adjustment, brake pads of dubious quality.
Features
When choosing a bike, the question often arises as to whether to choose an aluminum or steel bicycle frame. The final decision depends on the financial capabilities of the buyer, the purpose of the machine and the subjective requirements of the user. It is worth noting that in the manufacture of aluminum structures, thick-walled pipes of large diameter are used.
This is due to the fact that, according to the laws of physics, if the pipe size is doubled, its rigidity will increase eight times, and with a double wall thickness increase, the rigidity index increases by the same amount. Therefore, of the available options, increasing the diameter is preferable.
As a rule, the minimum pipe wall thickness on an aluminum frame is 0.8 mm. Often manufacturers make pipes by butting or using different sections, which also allows you to strengthen the product.
Used alloys
There are many aluminum alloys that bicycle frames are made of. The most common are the brands 7005T6 and 6061T6. The T index indicates that the material has undergone heat treatment. For example, an alloy product 6061 is heated to 530 degrees Celsius, then actively cooled by a liquid. Further, for 8 hours, the material is artificially aged at a temperature of 180 degrees. The result is an alloy of the grade 6061-T6. The analogue under number 7007 is cooled by air, not water.
Below are the comparative characteristics of materials before and after heat treatment (in brackets):
- Alloy 2014 (20146) - tensile strength is 27 (70) thousand PSL, yield strength - 14 (60), elongation percentage - 18 (13), Brinell hardness - 45 (135).
- Similar indicators of material 6061 (60616) - 18 (45), 8 (40), 25 (17), 30 (95).
The first alloy uses 4.5% copper, 0.8% carbon and manganese, 0.5% magnesium. The second material includes 1% magnesium, 0.6% silicon, 0.3% copper, 0.2% chromium, and about 0.7% iron.
Finally
The strongest is a 16 ”bicycle, the aluminum frame of which is made of 70005 or 7005 alloy. Nevertheless, the analogue 6061 is more technologically advanced, which makes it possible to produce pipes with a complex cross section, and this increases the strength of the product. In addition, such aluminum lends itself better to welding. When choosing the type of bicycle frame, consider the financial possibilities and the intended use of the bicycle. With proper use, a bike with a frame of any material, including steel, aluminum or carbon, will last quite a long time.