* Specifications and requirements for electric mountain bikes
As a competitive bicycle, the first, must be human driven; Second, is not allowed to install any windproof (reduce air resistance) equipment, but can install the transmission; Thirdly, the length of a bicycle shall not exceed 2 meters and the height shall not exceed 75 centimeters. The distance between the center axle and the ground shall be 24 — 30 centimeters, and the distance between the center axle and the front axle shall be 58 — 75 centimeters. The distance between the center axle and the rear axle shall not be less than 55 centimeters. The handlebars shall be no less than 75 cm in width. Wheel diameter, seat, frame form and so on May choose by oneself.
To ensure the safety of the athletes, the road racing cars must be flexible, with effective front and rear brakes and rubber or cork plugs in the handles. There must be no sharp parts in the car and no screws protruding.
* Inspection points
Electric mountain bikes need regular scrubbing to keep them clean. Use 50% oil mixed with 50% gasoline to wipe the electric mountain bike. Only wipe the car clean, in order to timely find the fault of each part, to repair, ensure the smooth progress of training and competition.
Athletes should wipe down their cars every day. By wiping, not only can keep the electric mountain bike clean and beautiful, but also can help check the good condition of all parts of the bike, cultivate the sense of responsibility and dedication of the athletes.
Attention should be paid when checking the vehicle: the frame, fork and other parts should not be cracked and deformed, the screws of all parts should be tightened, the handlebar can be flexibly turned. Each link of the chain should be carefully checked to remove the crack and replace the dead link to ensure the normal operation of the chain. Do not replace the new chain in the competition to avoid the new chain and old gear mismatches and chain loss. When it is necessary to replace, the chain should be replaced with the flywheel; All parts of the brake system are complete, the gap between the brake cover and the rim is suitable, and the brake is sensitive and effective; The flywheel and the transmission cooperate, each gear position USES freely, the transmission is quick, each spring’s expansion degree is moderate, the transmission line is smooth smooth. After each training or competition, the gear should be all back to reduce the spring pressure, extend the service life of the transmission; Check whether the rotation of each bearing part is good, whether there is any damage phenomenon, pay special attention to tighten the right middle wrist screw; The foot cover, leather strap and pedal shall be intact. The seat shall be parallel to the crossbeam and shall not tilt. The front and rear positions shall be moderate. Wheel alignment, if there is deflection or deformation, it will make the wheels jump up and down or left and right swing, must be corrected.
After each inspection of the vehicle, personally test the vehicle as a final verification check to ensure that it is in good condition and ready for use at any time.
* Electric mountain bike lubrication
The form of relative motion between parts of electric mountain bike is rolling motion and sliding motion. Rolling friction is generated at bearing parts, and sliding friction is generated between chains, sprockets, flywheels and other moving parts. To reduce the friction during movement, lubricants should be added at any time to change the direct friction between components into the relative friction with lubricants. Parts do not contact directly, dry friction into wet friction, reduce friction resistance. It is easy to ride and saves energy. Because the wet friction produces only one fortieth of the dry friction resistance. Therefore, the heat generated by wet friction is small, the parts will not be deformed due to overheating, reducing wear and protect the parts. Especially in rainy days when training and competition, more attention should be paid to add lubricants to the parts, to prevent water erosion caused parts failure or damage. Therefore, every e-mountain cyclist should pay special attention to the use of lubricants.
Use a moderate amount of lubricant. Sunny less plus some, otherwise it will stick to a lot of dust, affect the rotation; Add more when it rains (especially on the chain). When participating in multi-day race, it is better to bring a small oil can, and add lubricant to the chain every two hours to reduce friction, otherwise, the normal transmission of the chain will be affected, aggravating physical exertion.
When using butter (calcium-based grease), different types of oil should be selected according to the climate, training and competition conditions. Road racing should choose a higher hardness of 3# or 4# lubricants, the venue racing can choose 1# grease. Use a softer lubricant in winter and a harder one in summer.
* Tire maintenance and repair
The tyre of the racing bicycle is in the shape of a tube, and the tyre wall is very thin.
Bicycle tires are divided into several models according to weight. More than 250 grams of tires are used in daily road training, and 200-300 grams of tires can be selected according to the road conditions during the race. The thinner the tire, the smaller the surface of contact with the road, friction is also small, which is conducive to improve the speed of the car.
The purpose of injecting a certain amount of gas into the tire is to make the bicycle have a certain degree of elasticity and reduce the impact of radial jolting force on the rim. In the case of bicycle load, reduce the road surface contact with the tire to reduce friction. For this reason, during training and competition, the pressure in the tire should be suitable. Road tires generally maintain 5 — 7kg/cm2 air pressure, the best place to inject 10 — 12kg2/cm2 air pressure tires. If the air pressure in the tire is too high, the tire is easy to explode. If it is too small, the friction force between the tire and the ground will be increased, which will increase unnecessary physical consumption. The tire is also easy to slip off the wheel. Especially riding on the track, the tire pressure is smaller, more likely to slip off the wheel, a danger, leading to injuries to athletes.
Two hours before each ride to charge up the tire, and then check whether the tire leakage, the surface has no foreign bodies or stab parts. During breaks after summer training and RACES, keep your car in the shade to prevent the tires from expanding and bursting when heated. When preserving the tire, inject a small amount of gas, hang it, and place it in a dark and ventilated place. The humidity should not be too high to prevent the rubber from aging and deterioration.
If you need to change a new tire during the race, you should install the new tire in advance and ride at least more than 50 kilometers. Check whether the tire is good and confirm that there is no problem before use.
Repair of inner tube. The first is to find a hole. The method is to break the tire into the right amount of gas, into the water, the most bubbly place is where the hole. If air leakage is not easy to find holes everywhere, can be the tire valve mouth on both sides of the fold back, hand grasping or tied with a rope, do not let the gas through, another person to help pump, if soon after pumping gas leak, that near the valve mouth leakage; No air leakage or slow air leakage after pumping indicates that the hole is not here. Move the fold back and continue to examine each section until the hole is found.
After finding the air leakage place, disassemble the outer tube and take out the inner tube first. Do not pull hard to prevent the inner tube from breaking. Then with wooden file or hacksaw blade will be broken around file clean, or with gasoline wash clean, will be patched on the skin, and then the outer tire sewing. Do not pull the seam too tight, so as not to cause uneven thickness of the tire.
30 minutes of maintenance can systematically check the whole body of the bike. If the machinery is in good working order, the inspection will be finished soon. If there is a problem, it will take a long time to check the maintenance. The following sections provide detailed tips that you should pay attention to when performing car maintenance. Do-it-yourself maintenance, you can have a deeper understanding of the bicycle, and can check the mechanical operation of the bicycle is normal. This is best done in conjunction with regular cleaning. Before long, you’ll be able to intuit what’s wrong, and as soon as something looks, feels or sounds wrong, you’ll know where to look.