Steel idler sprockets maintain proper chain pressure, and guideline the chain around obstacles and prevent excessive chain put on and vibration. You don’t need any unique tightener shafts for ball bearing idler sprockets. Composite sprocket idlers require no lubrication and are corrosion resistant and wear-resistant.
An idler sprocket is a device used to maintain the strain in a chain or chain drive system. Often consisting of only a sprocket installed on a spring tensioned arm, the idler sprocket pulls against the chain in a continuous manner to keep the chain tight all the time. How big is the sprocket used in an idler sprocket assembly has no effect on the performance of the chain drive; however; a larger sprocket will often last longer due to the slower swiftness of the sprocket, which saves use on the sprocket’s bearings. Maintenance for the idler assembly is often no more than an intermittent greasing of the sprocket’s bearings.
When generating a machine by chain, the tension of the chain should be held at a constant in order to avoid the chain coming off of the drive sprockets. By installing an idler sprocket in the drive program, the chain is held taut while not being over-tightened. Working a chain in an over-tight condition can lead to premature bearing and chain failure while an idler sprocket positioned in the program is often a way to significantly extend the life of the chain, sprockets 
and the bearings on the machine’s sprocket shafts.
The ideal installation of the idler sprocket is on the opposite side of the chain between your drive sprocket and the driven sprocket. The application should place the idler sprocket in a position that has the sprocket pushing or pulling the chain towards itself since it loops the two main sprockets in a form similar to the letter B. This design allows the pulleys to pull the chain hard without hindering the idler in any way as the drive chain passes over the sprocket. If a condition occurs which requires the drive to exert excess strain on the drive chain, the idler will flex against the chain, and can expand while remaining in touch with the drive sprockets.
While the vast majority of idler sprockets are manufactured of steel, many components are used to manufacture an idler sprocket. Many poly or composite sprockets have already been used in combination with great success and some wooden sprockets are also used on some machinery without issue. Many machines, so that they can reduce the wear on the drive chain, use an aluminium, cast iron or steel sprocket covered in a nylon materials. The metallic hub allows the idler sprocket to stay very strong while the nylon covering is certainly soft on the chain links.
