Two Different Jobs, Two Different Parts
A tensioner pulley is spring-loaded or hydraulically actuated and continuously adjusts to keep belt tension within spec as the belt stretches with age and the engine shifts on its mounts. An idler pulley is fixed in position and exists only to route or wrap the belt around obstructions in the drive layout — it carries no tensioning mechanism.
JBMK manufactures both as distinct product lines built for their respective duty cycles. If your requirement is a fixed guide/routing pulley rather than an automatic tensioner, see our Sleeve / Idler Pulley page.
Sealed Double-Row Bearings
Pre-lubricated, sealed-for-life bearings rated for continuous accessory-drive duty.
Heavy-Duty Dust Shields
Protects the bearing and spring mechanism from under-hood debris and moisture.
Automatic & Fixed Variants
Spring-loaded automatic tensioners and fixed-tension assemblies to your drive layout.
IATF 16949 Certified Plant
Manufactured on the same quality-controlled lines that supply JLR, Hyundai, and Mahindra.