Okey dokey, driving season is back in full swing again and
Old Blue is back on the road. I've had what seems to be a
tire balance problem ever since I first brought my '50, 3604
home nearly ten years ago.
First year, never even drove it with the old tires. Soon as
I got it in the garage, I blasted the two piece rims, painted
with PPG enamel, had new flaps, tubes and bias ply tires
mounted on all 5 rims. Had them balanced and the vibration
was not what I expected. They ran square for the first ten
miles or so after sitting, and I mean real square, thought
the front clip was gonna shake right off the front of the
truck in the morning. Had them re-balanced, same thing.
So then the next year different rims from early 70's Chevy
4x4 3/4-ton, again, media blasted, PPG enamel, this time
new radials and balanced.
Better, but still appeared to be a balance vibration. Had
them balanced at a different tire shop, same thing.
Got the dial indicator out and checked tires, rims, hubs,
axles, all run true. Up on four 6ton jack stands to see if
it was in the drive line, no vibration at speed.
This time I found a shop who had just gotten a new road
force balancer and had them balanced another time simulating
the weight on the wheels.
Vibration still there. As a last resort I'd been reading
about balancing beads. Many truckers and bike users giving
positives, still don't understand how they can work but
thought it worth a try, so.....four bags of Dyna-Beads later
and it seems to get better but that cold have been the
placebo effect. after driving the truck with the beads for a
few years now, the vibration is still there and is really annoying.
My question is aimed pretty much straight at Longbox Bill
who is our resident tire expert. So Bill, what's your take
on Dyna-Bead?
I think Ken chimed in a couple of years back on the subject
and running a fleet of trucks might have tried them or not?
The problem with lead weights, or any fixed weight, is and
always has been, that the only time it is in perfect balance
is at that one speed it was balanced at or a harmonic of
that rpm. Centripetal force is proportional to the square of
the frequency.
One might try to compare this to balancing a crank shaft but
the difference is the conterweight is offset in an opposite
direction by the the rotating weight of the rod. The
reciprocating factor is present in an engine which isn't a
factor when considering the centrifugal forces in a wheel.
I left the lead weights on from the last time they were
balanced when I put the beads in, and I'm wondering if
that's not where the problem may be coming from. If indeed
the beads do work they would be a dynamic balanced as oppose
to the static balance that the wheel weights offer.
Denny Graham
Sandwich, IL
Last edited by cletis; 05/22/2015 4:42 PM. Reason: modified title
