Sec. 10
P a g e 65
drive a x le s should equal the sum of th e circu m fer
en ce s of the 4 tir e s on the rear of the tandem a x les.
T h is'p reca u tio n is n e c e ssa r y to prevent e x c e ssiv e
w ear from slippage. If th ere is a third differential
betw een th ese two drive a x le s, d isregard th is r e c
om m endation. L ik ew ise it is to be d isregard ed for
s e m i- t r a ile r tandem tir e s b ecau se th ese a re on
fr e e -r o llin g w h eels.
SYNTHETIC TUBES AND FLAPS
TUBES CHAFED OR PINCHED
BY FABRIC BREAKS
Tubes may fa il a s a r esu lt of being chafed or
pinched by fabric break s in sid e the tir e . The d irec
tion and shape of the tube in ju ries have rather
c lo s e ly follow ed the pattern of the fab ric breaks.
A tir e does not n e c e s s a r ily go flat im m ediately
when a fabric break o ccu r s on the in sid e of the tire
b eca u se it may take so m e tim e for the injury to
chafe com p letely through the tube.
TUBES DAMAGED BY
MISMOUNTED FLAPS
The tube may becom e chafed by a fold at the
edge of the flap. In mounting tir e s requiring flaps,
it is e sse n tia l that the flap s be p rop erly centered
betw een beads to prevent folds or w rin k les. Flaps
which have once becom e tw isted , c r e a se d , or folded
over at e d g es, should not be u sed again.
TUBES AND CASINGS DAMAGED
BY FOREIGN MATERIALS IN CASINGS
Any foreign m aterial between the ca sin g and
tube w ill cause a chafing action. In tim e , one or
both w ill becom e badly dam aged and fa il. The r e
su lt of g rit, peb b les, or other hard su b stan ces which
b ecom e embedded in the tube w all, w ill chafe tube
and finally cau se fa ilu re.
TUBES STRETCHED AND CREASED
When a tube is la r g e r than the in sid e of the
WHEELS AND TIRES
T-8305
Figure 14—Im pro per Tube Inflation
casin g it has b ecom e stretch ed and can becom e
cr e a se d . C reasin g can a lso happen to a new tube
of proper s iz e when in co rrectly mounted. If the
cr e a se o ccu rs in the flexin g area of the tir e , the
resulting additional th ick n ess of the tube w here
folded c a u ses a hinging action which cuts the tube
and frequently dam ages the fabric - resu ltin g in a
costly failu re.
CREASES CAUSED BY
REMOUNTING USED TUBES
Tubes usually undergo som e stretch or growth
in s e r v ic e . T his is p articu larly true of truck tubes
becau se of the high tem p eratu res which develop.
When a u sed tube is rem ounted in a new, or nearly
new tir e , a folded condition w ill usu ally r e su lt,
and eventually w ill cau se both tube and tir e to fa il.
Figure 15—Proper Tube Inflation
