On Apr 6, 11:29*pm, "Leo Lichtman"
wrote:
"William Noble" *wrote: What I was trying to say by "increased sensitivity"

I had a difficult speed-sensitive tire vibration problem on my old
Ranger and made a static tire balancer to help solve it.

Actually an upper shock mount had rusted out. The lip that trapped
road salt also hid the damage. I had to replace the front spring
hanger plate.

The hub adapter is a disk that seats in a machined countersink in the
center hole of the alloy wheels. I tapped the center of the disk
1/2"-20 and bored a conical hole in the threaded end of the hex bolt
that goes into it. It balances on an upright point made of music wire.
Is that clear without a picture?

Screwing the 1/2-20 bolt in or out (up or down) adjusts the
sensitivity by moving the balancing point axially towards or away from
the center of gravity of the wheel. If I turn the bolt in until the
wheel always tips sideways, then back it out until the wheel just
barely balances, a 1/8 ounce wheelweight tips the wheel noticeably.
It's so sensitive that it doesn't need a bubble. It also wore so
quickly that the point needed to be sharpened after every wheel.

This was a useless exercise caused by misreading the problem but it
shows how balancing works. Suspend the wheel at its exact center of
gravity and it will be stable in any position. When I moved the
suspension point 0.010 - 0.020 above the center of gravity the tire
balanced level but a nickel (5 grams) was enough to tilt it.

The height of the stand under the balance point has absolutely nothing
to do with sensitivity, just convenience.

Jim Wilkins