The Balmar AltMount Serpentine Pulley is a ten-groove J10 pulley for Balmar 95 Series alternators, 2.7 inches in diameter with a 0.875-inch bore.
Pulley diameter sets alternator speed relative to the engine, so 2.7 inches is a specification rather than an incidental dimension. A smaller pulley spins the alternator faster and improves low-rpm output; a larger one reduces peak speed. Substituting a different diameter changes charging behavior across the whole rev range.
The 0.875-inch bore has to match the alternator shaft, and it is specific to Balmar 95 Series units. A pulley from another alternator will not fit, and forcing one on damages both the shaft and the bearing behind it.
Ten ribs give greater belt contact than a single-V pulley, which is what a high-output alternator needs. This is the alternator-side component, so the engine drive has to already be on a J10 serpentine profile. Explore more alternator mounts and pulleys.
- 2.7 inches sets alternator speed against the engine
- A smaller pulley improves low-rpm output
- 0.875-inch bore is specific to 95 Series units
- The engine drive must already be J10
