1. Vehicle condition inspection
Normal riding does not require any technology, but it is the most important and basic item in bicycle maintenance. Before riding, it is very important and often forgotten to check the condition of the bike. Therefore, remember to do the following checks before riding:
Check the riding posture and size: If you are not riding your own bike, remember to adjust the seat cushion to the appropriate height before riding.
Check the screw tightness of each part: check whether the quick release of the front and rear wheels and the seat cushion rod is locked, check whether the handlebars are fixed, and check whether other screws are loose.
Check the tire: check whether the tire pressure is sufficient, if not, turn it to the appropriate pressure, check whether the tire wall has cracks, whether the cut tread is too shallow, and replace the outer tire if necessary.
Check the brake: pull the front and rear brakes, and check whether the brake can stop.
Check the front wrist: brake the front brake and shake the body back and forth. If there is a shaking gap, it means that the front wrist must be readjusted.
Check the transmission: after starting, try to change the front and rear transmission respectively. Check whether the speed can be changed smoothly to each gear, and whether there will be strange noises.
2. Lubrication
Bicycles are human machinery with a large quantity and a wide range of applications. The lubrication structures include sliding friction and rolling friction, point friction and line friction, fluid lubrication and boundary lubrication, oil lubrication and grease lubrication.
The key sports friction parts of a bicycle are the central axle, front and rear axles. Both use ball bearings, lubricated with No. 2 calcium base grease. During each maintenance, the ball, the ball groove and the guard cover shall be cleaned, and 2 # calcium base grease shall be evenly applied to the ball groove. Special balls (beads) with smooth and complete surfaces, uniform particles and the same size shall be placed around the shaft, and then the guard cover shall be installed to prevent dust and impurities from mixing. However, it is a special case on bicycles. In order to simplify the equipment, there is no grease fitting, and only lubricating oil is added to improve lubrication.
Secondly, the lubrication of the chain and the gear disc. This is the mixed friction of sliding friction and rolling friction, and most of them are in the boundary lubrication state, so the friction conditions are harsh. Therefore, we must use lubricating oil with good adhesion and lubricity, especially most of them are open type. They work under the condition of more dust, and wear the chain and the gear disc seriously. Therefore, they should be cleaned at any time (quarterly or half a year) according to the situation, Replace with a new oil. The lubricating oil with higher viscosity (40 °C viscosity 10-20mm2/s) is most commonly used, but the same lubricating oil is generally used as the one added to the triaxial shaft, which is more convenient.
