Smooth Idler Pulley 100mm
Select Modular Ford Applications, Including 2003-2004 Mustang Cobra, 1999-2004 Lightning, Supercharged Harley Davidson F150
Single-Bearing or Double-Bearing
These billet idler pulleys are custom-sized at 100mm (3.9”). This specific diameter is a benefit in supercharged applications, such as in the auxiliary idler position where the additional belt wrap at the supercharger pulley serves to reduce belt slippage. The larger diameter of this pulley serves to improve belt wrap in any position on the engine, results in slower speeds at the pulley bearing, which adds to longevity and reliability, and most prefer the appearance of the larger face of the pulley. In applications such as the Mustang Cobra or Lightning truck, these 100mm idler pulleys can often be installed as direct replacements for the original 90mm idler pulleys. Please note that the Mustang Cobra requires at least one 90mm idler in the center position of the blower drive to maintain proper belt clearance.
Like all Metco idler pulleys, these pulleys are CNC-machined from certified 6061 billet aluminum. We machine the bearing bore and the belt surface as part of the same machining operation on our CNC lathe to eliminate the possibility of pulley runout or wobble. An application-specific hardcoat anodizing is applied to the belt surface, bearing bore, and backside of the pulley to maximize strength, resist corrosion, and minimize belt noise. High-speed, high-load bearings with large steel rollers, heavy grease, and double grease seals are precision-fit into the center bore, and a snap-ring ensures everything stays in place.
Following machining, plating, and assembly, each pulley is spun on a fixture to ensure that it meets our high standards prior to packaging. Each pulley ships with the billet bearing cover and high-quality stainless steel fasteners, as shown.
These 100mm idler pulleys are offered in two configurations. The 8-rib (1.5” wide) single-bearing version is intended for use on the supercharger drive of the Mustang Cobra, Lightning truck and Harley Davidson F150 applications. These single-bearing pulleys are our most popular, and in a properly set up system, should be expected to be a permanent solution to the problem of failure-prone OEM idler pulleys. The 10-rib version of our 100mm idler pulley is a double-bearing pulley, fitted with two of the heavy-duty bearings, which serves to spread the load from the supercharger belt over twice as much surface area. This design adds a significant amount of load capacity, and is recommended for use in severe applications, such as those running very high belt loads and boost levels, or where the supercharger belt is tighter than recommended. Note that the 10-rib pulleys are 1.75” wide at the belt surface, and while these pulleys fit perfectly in the Cobra and Lightning applications, these pulleys are wider than the original pulleys.
Important note: When an existing 90mm pulley is replaced with a larger 100mm pulley, 0.5” must be added to the required belt length. In the case of the Mustang Cobra, where there are often (3) 100mm idlers used on the blower drive, a total of 1.5” should be added to the calculated belt length.
This price shown is for (1) pulley. Feel free to call or email if you have any questions.