A bicycle chain should be oiled every few weeks or after 150-200 km of riding. If it appears dry, makes noise or feels rough while pedaling, applying lubricant ensures smooth movement and prevents rust.
Class 6 Vocational Education Kaushal Bodh Textbook chapter 3 Project 3 Maker Skills question answer
Class 6 Vocational Education Kaushal Bodh Grade 6 Project 3 Maker Skills solutions