Pontiac Fiero 1988 Service Manual page 209

3E-6 TIRES AND WHEELS
MEASURING WHEEL RUNOUT
•IF W H E E L
DESIGN WAKES THIS OUTBOARD
MEASUREMENT IMPOSSIBLE, THE INBOARD
SIDE ONLY MAY BE USED
TI R E R E M O V E D F R O M W H E E L
RADI A L R U N O U T RADI A L R U N O U T
I N BOARD SI D E
O U T B O A R D SI D E
G33959-3E-AN
Fig. 10 Wheel Runout
S P A R E TIRE
Compact Spare
Fig.
11
Some models will be equipped with a high
pressure compact spare. The compact spare uses a
narrow 4-inch wide rim, although the wheel diameter
is usually one inch larger than the road wheels.
The compact spare wheel should not be used with
standard tires, snow tires, wheel covers or trim rings.
If such use is attempted, damage to these items or other
parts of the car may occur. The compact spare should
be used only on cars which offered it as original
equipment.
Inflation pressure of the compact spare must be
periodically checked and maintained at 415 kPa (60
psi). It can be mounted and dismounted from its wheel
using present tire changing equipment and procedures.
As with other tires, the beads should completely seat
at 275 kPa (40 psi). The tire may then be safely inflated
to 415 kPa (60 psi).
C A U T I O N : T o a v o i d s e r i o u s p e r s o n a l
i n j u r y , d o n o t s t a n d o v e r t i r e w h e n
i n f l a t i n g . B e a d m a y b r e a k w h e n b e a d
s n a p s o v e r s a f e t y h u m p . Do n o t
e x c e e d 2 7 5 k P a (40 p s i ) p r e s s u r e
w h e n i n f l a t i n g a n y t i r e if b e a d s a r e n o t
s e a t e d . If 2 7 5 k P a ( 4 0 p s i ) p r e s s u r e
w i l l n o t s e a t b e a d s , d e f l a t e ,
r e l u b r i c a t e t h e b e a d s a n d r e i n f l a t e .
O v e r i n f l a t i o n m a y c a u s e t h e b e a d t o
b r e a k a n d c a u s e s e r i o u s p e r s o n a l
i n j u r y .
COMPACT
S P A R E
• Temporary
Use Only
• Inflate to
6 0 PSI
G33961-3E-AN
Fig. 11 Compact Spare
MATCH MOUNTING
Fig. 12
Tires and wheels are * 'match-mounted'' at the
assembly plant. This means that the radially stiffest
part of the tire, or "high spot", is matched to the
smallest radius or "low spot" of the wheel.
The "high spot" of the tire is originally marked
by a yellow paint mark or adhesive label on the
outboard sidewall.
The "low spot" of the wheel will be at the location
of the valve stem.
Before dismounting a tire from its wheel, a line
should be scribed on the tire at the valve stem to assure
that it is remounted in the same position.
Replacement tires and wheels that are of original
equipment quality will have their "high and low spot"
marked in the same manner.
VALVE STEM ALIGNED
WITH TIRE'S PAINT
DOT OR LABEL
G33962-3E-AN
Fig. 1 2 Matched Tires and W h e e l s
BALANCING TIRE AND W H E E L
Figs. 13 and 14
There are two types of tire and wheel balancing,
static and dynamic. Static balance is the equal
distribution of weight around the wheel. Assemblies
that are statically unbalanced cause a bouncing action
called wheel tramp. This condition will eventually
cause unpvpti —