All these errors are similar to errors and
results made when measuring track bushings.
Depth Gauge Measurement
1. Set the farthest probe on the measurement
tool as an outerflange reference hook.
Then set the probes in the numbered holes
for the model being measured.
2. On machines with elevated sprockets
the probes should be resting in the wear
cusps on the roller tread. For all other
machines the probes should be adjusted
to the most worn surface.
3. Push the bar down flush with the
flanges. Then measure the exposed
length of all tread probes and use the
largest measurement to determine
percent worn.
Ultrasonic Wear Indicator
Measurement
The ultrasonic wear indicator measures the
distance from the wear surface of the
roller to the inside diameter of the roller. It
is important not to measure to the retainer
bolt holes.
On elevated sprocket machines and hydro-
static loaders with retainer rollers, observe
the location of the retainer bolts and place
the probe between them.
The new series machines have new improved
track rollers. This new design eliminates
the need for retainer bolts by using a snap-
ring. As a result of this design, serviceabil-
ity has improved and using the ultrasonic
wear indicator is easier (without bolt holes,
measuring can be done anywhere on the
surface of the roller).
On low sprocket track-type tractors,
former track-type loaders, and excavators,
the retainer bolts are not visible. For these
rollers, observe the thickness readout
closely from roller to roller to catch any
abnormally small thicknesses which
would indicate a reading to the bolt hole.
On track rollers with noticeable cusp wear,
slide the probe across the cusp to get
the smallest reading. To speed the process,
select the cusp that normally is most worn
(the cusp closer to the center of the roller),
rather than sliding the probe over both
cusps each time.
Rear and Front Rollers
Most Important
If roller guards or other conditions prevent
measurement of all rollers, then the most
important roller to be measured or estimate
wear on is the rear roller. The next most
important roller to be measured is the front
roller. These two rollers should definitely
be inspected by any means possible that
does not present a safety hazard. The rear
and/or front rollers generally will be most
worn and therefore critical in maintenance
and servicing decisions.
Wear Limits
Allowable wear on roller treads and result-
ing wear limits have been determined as for
the link, by allocating some fraction of the
roller flange to pin boss (or bushing) clear-
ance as appropriate. This is based on the
assumption that the average roller wear will
equal link wear. Since front and/or rear
rollers usually wear at a faster rate than
center rollers it should be assumed that the
front and rear rollers will reach service or
destruction limit prior to links and therefore
be the first cause of pin boss to roller flange
interference. For example, 90 percent worn
links may still experience pin boss to roller
flange interference even though average
roller wear is only 90 percent. This is
because the rear roller is 110 percent worn.
(See discussion on “Roller Swapping”).
62
TRACK ROLLERS
General Information