Your Guide to Selecting the Right Shorter Belt for Your JS Alternators High Output Alternator
Last updated: May 2026
Your JS Alternators high output alternator requires a shorter serpentine belt. This guide covers how to select the correct belt for your vehicle.
How to Find Your Belt
JS Alternators includes the exact belt specification (part number and size) with every order. The belt is typically 1-2 inches shorter than the factory belt to compensate for the larger alternator case diameter.
Belt Brands
Gates, Dayco, and Continental are the recommended brands. All three are available at most auto parts stores (AutoZone, O'Reilly, Advance Auto, NAPA). Use the part number from your JS Alternators order slip.
Installation
Route the new belt following the same path as the original, using the belt routing sticker in your engine bay. Use a serpentine belt tool or breaker bar on the tensioner pulley to release tension when routing.
Full installation guide: How to Install a High Output Alternator: Step-by-Step
Why the belt is different: Why Do I Need a Shorter Belt?