Chevrolet 10 Series 1970, Руководство по обслуживанию

Страница: 539 / 671

WHEELS AND TIRES 10-9
CKP 10 SERIES CKP 20 , C P 3 0 SERIES
C P 30 W /D U A L REAR
40, 50 SERIES
CDLST >0 SERIES
....
j
50, 60 SERIES
60 SERIES
F ig . 3 — Rear W hee ls and A tta c h m e n ts
In som e cases this fin is alm ost as pronounced as a to e -
in fin , and in others, it ta p ers into a row o f tread blocks
to such an extent that the t ir e has a d efin ite "step w e a r"
appearance.
T h e only rem edy fo r co rn erin g w ea r-is p ro p er in stru c­
tion of o p era to rs. D riv in g m ore slow ly on cu rves and
turns w ill avoid grinding rubber o ff t ir e s . T o o ffset n o r­
m al corn erin g w ea r as much as p ossib le, tir e s should be
interchanged at reg u la r in te rv a ls .
W h eel and Tire Balancing
It is d esira b le fro m the standpoints o f t ir e w ea r and
ve h ic le handling ease to maintain p ro p e r balance o f fron t
wheel and t ir e a ssem b lies on a ll m odels. A ll w heels in ­
tended fo r use on fron t of v e h ic le , such as those switched
during p e rio d ic t ir e rotation and those installed as new
o r re p a ire d replacem ent equipment should be accu rately
balanced. T h is may be accom plished by eith er o f the two
types o f balancing system s in cu rren t use which balance
w heels eith er on the v e h ic le o r o ff. T h e "on the v e h ic le "
type, h ow ever, is the m ore d esira b le in that all ro llin g
components (brake drum s, b ea rin gs, s ea ls, etc.) a re in­
cluded in the balancing proced u re and thereby have any
existin g unbalance co rre c te d .
Truck W h eel Balance W eights
A ll 1969 truck w heels equipped with a tubular side ring
(ro lle d flan ge rim ) on the outboard side o f the wheel rim s
re q u ire sp ecial design w eights to fit. Dynam ic balancing
can be accom plished through use o f these sp ecial balance
weights which a re designed only fo r installations on the
outboard side of th ese w heels. Conventional w eights fit
only the inboard side of these w heels.
Static Balance
Static balance (som etim es c a lled s till balance) is the
equal distribution of weight o f the wheel and t ir e a ssem ­
bly about the axis of rotation in such a manner that the
assem b ly has no tendency to rotate by its e lf, re g a rd le s s
of its position.
F o r exam ple: A wheel with a chunk of
d irt on the rim w ill alw ays rotate by its e lf until the heavy
side is at the bottom. Any wheel with a heavy side lik e
this is sta tica lly out of balance. Static unbalance of a
wheel causes a hopping o r pounding action (up and down)
which frequ en tly leads to wheel "flu tte r " and quite often
to wheel "tra m p ".
Dynam ic Balance
Dynamic balance (som etim es ca lled running balance)
means that the wheel must be in static balance, and also
run sm oothly at a ll speeds.
T o insure successful, accurate balancing, the fo llo w in g
precautions must be observed:
• W heel and t ir e must be clean and fr e e fro m a ll fo re ig n
m atter.
• Th e tir e s should be in good condition and p ro p e rly
mounted with the balance m ark on the t ir e , if any, lined
up with the v a lve.
• Bent w heels that have runout o v e r 1/16" on 1/2, 3/4
and 1 ton, o r 1/8" on 1-1/2 and 2 ton trucks should
eith er be replaced o r straightened b efo re being b a l­
anced.
• Inspect t ir e and w heel assem bly to d eterm in e if an
eccen tric o r ou t-of-rou n d condition e x ists. N ote that
this condition, i f s e v e r e , cannot be "balanced ou t". An
assem bly which has an out-of-round condition e x ceed ­
ing 3/16" on t ir e s iz e s through 19.5" and 3/16" on
s iz e s la r g e r than 19.5", is not suitable fo r use on the
fron t o f the v e h ic le . Its use on the r e a r should be
governed by its gen eral condition and whether the
roundness d efect s erio u sly detracts fro m o v e r a ll rid e
quality.
• When balancing w heels and t ir e s , it is recom m ended
that the instructions co v e rin g the operation o f the wheel
balan cer being used be c lo s e ly follow ed .
WHEELS
Two-Piece W heels
It is p o ssib le to m ix d iffe r e n t-s iz e wheel d iscs and
CHEVROLET TRUCK SERVICE MANUAL