Hummer H1 (2006+). Manual - part 218

6-22

Wheels and Tires/Central Tire Inflation System (CTIS)

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WARNING:  Always use a tire inflation cage for inflation purposes. Stand one side of cage during inflation, never
directly in front. Keep hands out of the cage during inflation. Inflate assembly to recommended pressure using a
clip-on air chuck. Do not exceed 50 psi (345 kPa) cold inflation pressure. Failure to follow these instructions may
result in serious injury or death.

12. Before installing the valve core, inflate the tire to seat the beads. Use of a tire bead seater may be required.

13. Install the valve core, inflate the tire to recommended tire pressure and install the valve cap.

14. Check for leaks around the wheel edges, the quick disconnect valve and the CTIS hose with soapy solution.

15. Balance the wheel/tire assembly with 15 oz. maximum weight. Refer to tire balance procedure in service manual if necessary.

16. Install the wheel/tire assembly on the vehicle.

a.

Roll the wheel/tire assembly to the vehicle.

b.

Place the wheel/tire assembly on the geared hub spindle studs.

c.

Start the lug nuts by hand.

d.

Snug the lug nuts.

e.

Lower the vehicle.

f.

Torque the lug nuts evenly and sequentially to 110 lb-ft (149 N•m)(Figure  6-25).

If the vehicle is equipped with CTIS perform these additional steps:

g.

Lubricate the threads on the CTIS fitting with teflon pipe sealant.

h.

Install the fitting in the geared hub spindle.

i.

Engage the quick disconnect fittings on all four wheels.

17. Install the lug cover.

Figure 6-25:   Lug Nut Tightening Sequence

Inspecting Tire Tread Wear

Tire tread wear is a good indicator of the tire balance and the suspension condition. Unbalanced tires often cause cupped or scal-
loped tread wear patterns (Figure  6-26). The tire wear inspection should be performed for all vibration complaints. Resolve the tire
wear problems before continuing with diagnosis.

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 Wheels and Tires/Central Tire Inflation System (CTIS)  6-23

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Figure 6-26:   Tire Wear Patterns

WHEEL AND TIRE BALANCING

NOTE: If an excessive vibration condition exists after normal balance procedures are performed, refer to the Wheel End Vibration
Correction Using Road Force Values procedure in section 6.

General

There are two types of tire and wheel balancing: static and dynamic. Static balance is the equal distribution of weight around the
wheel circumference. Wheels that are statically unbalanced cause a bouncing action called vehicle shake and possible steering nib-
ble or oscillation. This condition will eventually cause uneven tire wear (Figure  6-27).

Figure 6-27:   Static Imbalance Correction

RIGHT

FRONT

UNDERINFLATION

OVERINFLATION

MULTI-PROBLEM

RIGHT

FRONT

TOE-IN WEAR

CAMBER WEAR

OR CORNERING

TOE-OUT WEAR

STEERING WHEEL NIBBLE

ADD BALANCE

WEIGHTS HERE

HEAVY SPOT

12-1-05

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Wheels and Tires/Central Tire Inflation System (CTIS)

_______________

Dynamic balance is the equal distribution of weight on each side of the center line, so that when the wheel spins there is no ten-
dency for it to move from side to side. Wheels that are dynamically unbalanced may cause wheel shimmy, vehicle shake or a steer-
ing wheel vibration called nibble or oscillation (Figure  6-28).

Figure 6-28:   Static Imbalance Correction

NOTE: Most electronic off-vehicle balancers are more accurate than on-vehicle spin balancers. They are easy to use and give a dy-
namic (two-plane) balance. On-vehicle balancing is not recommended. When balancing off-vehicle, the wheel should be mounted
to the balancer with a cone through the back side of the center pilot hole or by the wheel (spindle) stud holes. The spindle stud
method is recommended for CTIS wheels.

Balancing

1.

Remove the wheel and tire assembly from the vehicle.

WARNING:  Remove all stones and foreign material from the tire tread before spin balancing. Failure to follow this
warning may result in injury.

NOTE: Deposits of foreign material must be cleaned from the inside of the wheel and the tire tread to obtain a good balance. The
tire should be inspected for obvious damage, then balanced according to the equipment manufacturers recommendations.

2.

Mount the wheel and tire assembly, curb side out, on dynamic balancer and start the balance cycle (Figure  6-29).

Figure 6-29:   Dynamic Balancer Mounting

STEERING WHEEL NIBBLE

ADD BALANCE 

HEAVY SPOT

WEIGHTS HERE

CURB SIDE

WHEEL AND

TIRE ASSEMBLY

DYNAMIC BALANCER

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 Wheels and Tires/Central Tire Inflation System (CTIS)  6-25

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3.

Locate and mark the wheel and tire assembly light spot on the tire (Figure  6-30).

4.

Record the weight and the position readings.

Figure 6-30:   Marking Wheel and Tire Assembly Light Spot

NOTE: If more than 15 oz. of weight is required to balance the tire, wheel and run flat (if installed) assembly, rotate tire 180° on
wheel. All aluminum wheel and tire assemblies require the use of tape-on weights only. Do not use wheel balancing liquids to bal-
ance the wheel and tire assembly. Balancing liquids may be incompatible with and cause damage to wheel, tire, run flat, and CTIS
components.

NOTE: There is very little clearance between the geared hubs and the inside diameter of the wheels. When installing tape-on bal-
ance weights on the inside diameter of the wheel, position the weights to afford adequate clearance to the geared hubs.

5.

Attach the balance weights to the inner and/or outer edges of the wheel (indicated by dynamic balancer), ensuring the weight
is centered on the light spot, or weights are placed evenly to the sides of light the spot if more than one weight is used. (Figure
 6-31).

6.

Start the balance cycle and repeat steps 3 through 5 until the tire is properly balanced.

7.

Remove the wheel and tire assembly from the dynamic balancer and install on the vehicle.

LIGHT SPOT