Bowmen of Skelmersdale

Changing Bow balance 1 - Using Weight

Moving centre of gravity using weights is simple. To move it forwards,place more weight in front of the centre of gravity or take weight off behind the centre of gravity.

To move centre of gravity backwards, place more weght behind or remove weight in

front. The same principles apply for upwards and downwards - add weight in the direction you want to move, or take it away from behind . Notice that the reference point is the centre of gravity, not necessarily the riser itself, though in most cases weights are added so far out as to make the distinction unimportant. But remember when adding weight very close to the riser that the centre of gravity may not change in the direction expected.

Exercise 1: Without stabiliser weights fitted, suspend your own bow from the top limb

nock. Note whether the vertical line from the suspension point falls. Is it in front of, or behind, the grip? Now suspend the bow from the string, near the grip.

Does the vertical pass above or below the normal hand position?

Exercise 2: Fit your normal stabiliser weights and repeat the exercise above. Where

is the centre of gravity now? Experiment with different weight combinations to see

how far different weight arrangements move the centre of gravity.

Weights and Distances - ‘Moment’

The balance of the bow, or the position of the centre of gravity, can also be understood in terms of the moments of all the weights in the system (including the riser, limbs etc. The Moment of a force about a point is the force multiplied by the distance to the point (measured at right angles to the direction of the force). For understanding balance, this is almost easy; all the forces are downwards, so all that matters is how far away from the suspension point the weights are, and how heavy

they are. In practice, there is one simple rule of thumb:

“Half the weight at twice the distance has the same effect on balance”

What bow behaviour needs controlling?

Bow  movement

Timing - When is movement important?

Time and Motion

Controlling bow displacement

Weight, Mass and Inertia

Static and Dynamic properties

The misnamed TFC

Controlling bow balance

Centre of Gravity

Finding the centre of gravity

Changing the balance using weight

Weights and Distances

Rods, weights and risers

Controlling bow vibration

Causes of Bow Vibration

Reducing Vibration - Damping

Bow Resonance

Tuned damping - more on TFC’s