The quality requirements of a flywheel are flexible rotation, no jamming during reverse rotation, and whether it is a regular or premium grade flywheel, it should meet this requirement. Additionally, a tolerance value of 0.30mm is required for the circular runout (radial runout) of the flywheel, 0.30mm for the radial runout of the foot brake and variable speed rear axle small sprocket, and 0.38mm for the end face circular runout mobilization.
The measurement method is to position the flywheel or foot brake, and the small sprocket of the variable speed rear axle according to the assembly reference, screw it into the standard spindle, and install it on a dedicated frame for measurement. When measuring, turn the spindle clockwise (to rotate the flywheel outer sleeve and core simultaneously).
Radial circular jumping momentum, measure the four points at the bottom of the tooth in equal parts (if less than or more than equal parts, measure adjacent points according to the principle of equal parts). The difference between the maximum and minimum values measured is called the runout. Measure the circular runout of the end face, measure the root of the tooth, and after measuring the flywheel for one revolution, rotate the outer sleeve 90, 180, and 270 times each. The data obtained from the four measurements shall be based on the maximum value, which is the largest measurement.
Scoring power method:
Inspection quantity: 4 pieces
Single item score: 0.375, actual score of 0.75 for each item,
Project score: 3
Measurement of pedal axis impact strength
The quality requirement for the pedal shaft is that when the pedal shaft is subjected to a 5 kg heavy hammer impact, the permanent deformation shall not exceed 6mm.
In addition, it is required that the foot pedal components rotate flexibly and without any jamming during rotation.
The method for measuring the impact strength of the pedal axis is to rotate the pedal axis 
One end is fastened to a dedicated rack. Measure 10mm away from the impact point before impact, and then measure again after impact. The difference between the measured values before and after impact is the permanent deformation. During impact, use a 5kg hammer to freely fall from a height of 300mm for impact, and the shape of the hammer's head should comply with the drawings.
Scoring method:
Inspection quantity: 2 pieces each for left and right foot pedals
Single item score: 0.5 for heavy-duty and ordinary models, and 0.25 for lightweight models
Project scores: heavy-duty, ordinary type 2, lightweight type 1
We are Ningbo Shenglu Auto Industry Co., Ltd., a professional supplier and manufacturer of bicycle accessories. There are mainly five series of products, including bicycle brakes, center axles, axle covers, bowl sets, and dental discs. Bosses in need can contact our online customer service or send an email. website: https://www.hubs-sf.com
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