[gregs210]

Jaybro, who's avatar are you complaining about?

Ramp, it's not a dumb question, HBs are amazing little things. Okay, maybe not so little; at least not light. In any event, internal combustion engines generate some nasty rotational vibrations and when the peaks and valleys (amplitudes) of these various vibrations coincide, they kind of build on one another and they can become violent. Aside from being a serious intrusion into a quiet, smooth ride, they have the potential to do engine damage.

The typical HB is a heavily-weighted, evenly-balanced thick disk that bolts on to the front of the crankshaft and is keyed to the crank so it rotates with it. Then there is a thin layer of compressed composite around the perimeter of the disk, usually a rubber composite compound, and then another wrap of metal is around that. Since the outer band of steel/alloy is not keyed to the crank, it flexes the composite sandwiched layer, the effect of which is to dampen the amplitudes. Thus, it "balances" the harmonics, so it's an harmonic balancer.

What impresses me is that someone actually thought something like that up. :)

Take care and enjoy the ride,
Greg