What Is a Weighted Socket? | Extra Mass For Stubborn Bolts

For the full breakdown, see our best Weighted 19mm Socket guide.

When a crankshaft pulley bolt refuses to budge, the fix often comes down to how well the socket transfers an impact wrench’s blows. A weighted socket adds mass to the body — through a thicker wall, a weighted collar, or solid construction — so the socket flexes less and more of the tool’s torque reaches the bolt instead of being absorbed by the socket itself.

How A Weighted Socket Works

The added mass does two jobs. First, it reduces “impact losses” and distortion during use. Second, the extra inertia helps the socket resist acceleration, which lets the impact mechanism deliver sharper, more effective blows. Laser Tools describes the design as “extra mass equals extra bite” for professional workshops tackling very tight fixings.

These sockets are not a standardized universal category. They are a niche marketing and usage term covering several related impact socket designs — weighted impact sockets, counter-weighted crank-bolt sockets, and harmonic balancer sockets. All share the same practical purpose: removing stubborn, high-torque crankshaft pulley and harmonic balancer bolts.

What To Look For In A Weighted Socket

Weight alone is the wrong selection criterion. Drive size, profile, and exact bolt size matter more. Most documented examples use a 1/2-inch square drive with 6-point (single hex) profiles in metric sizes. The socket must match both the impact wrench and the fastener.

The table below shows representative examples of weighted and high-mass sockets from the sources reviewed.

Safety And Compatibility Cautions

Weighted sockets are impact tools, not standard chrome hand sockets. Using them outside impact applications risks damage unless the product explicitly says otherwise. Matching drive size and socket size to the fastener is critical — a mismatch can round bolts or cause tool slip on high-torque jobs.

There is also a physical limit to how much mass a drive tool can carry. Atlas Copco’s socket guide warns that the maximum weight attached to a 3/8-inch square drive with ball retainer must not exceed 0.5 kg. That caution matters when adding mass to any drive tool, not just weighted sockets.

The most common mistake is treating “weighted socket” as a single standardized product category. In practice, it covers several closely related designs, and the practical benefit depends on impact-duty construction and the intended automotive use. Another frequent error is selecting by weight alone instead of by drive size, profile, and exact bolt size.

If you are shopping for one, you will likely need a 1/2-inch drive impact wrench and the correct metric size for your target bolt. For GM LS engines, a 24 mm hex pulley damper bolt requires a matching 24 mm socket. Before you buy, check the live product page for current pricing, since published prices change and the product listings are the only reliable source for them. For a tested roundup of the best weighted 19mm socket options, our hands-on review covers what actually works.