Basic Tire Knowledge

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2 Common Standard Tire Sizes:
  • 1. 315/80R22.5
  • 2. 10.00R20
For more details, view the pictures below:

Example 1: 315/80R22.5




  • A Nominal Section Width (mm)
  • B Nominal Aspect Ratio
  • C Radial Structure Code
  • D Nominal Rim Diameter (in)
  • E 154/150M
  • 154: Load Index (Single)
  • 150: Load Index (Dual)
  • M: Speed Rating
  • F Ply Rating
  • G Tubeless Tire
  • H Regroovable Indicator
  • I Pattern Name
  • J Belt Winding Direction
  • K Tire Rolling Direction

The table below lists the appropriate speed rating with the corresponding load index

Example 2: 10.00R20




  • A Nominal Section Width (in)
  • B Radial Structure Code
  • C Nominal Rim Diameter (in)
  • D 154/150M
  • 154: Load Index (Single)
  • 150: Load Index (Dual)
  • M: Speed Rating
  • E Ply Rating
  • F Tubeless Tire
  • G Regroovable Indicator
  • H Pattern Name
  • I Belt Winding Direction
  • J Tire Rolling Direction

The table below lists the appropriate speed rating with the corresponding load index

Speed Rating

SI Km/h
B 50
C 60
D 65
E 70
F 80
G 90
J 100
K 110
L 120
M 130
N 140
P 150
Q 160
R 170

Load Index

LI kg LI kg LI kg
115 1215 136 2240 157 4125
116 1250 137 2300 158 4250
117 1285 138 2360 159 4375
118 1320 139 2430 160 4500
119 1360 140 2500 161 4625
120 1400 141 2575 162 4750
121 1450 142 2650 163 4875
122 1500 143 2725 164 5000
123 1550 144 2800 165 5150
124 1600 145 2900 166 5300
125 1650 146 3000 167 5450
126 1700 147 3075 168 5600
127 1750 148 3150 169 5800
128 1800 149 3250 170 6000
129 1850 150 3350 171 6150
130 1900 151 3450 172 6300
131 1950 152 3550 173 6500
132 2000 153 3650 174 6700
133 2060 154 3750 175 6900
134 2120 155 3875 176 7100
135 2180 156 4000 177 7300
Tire Dimensions
  • S: Section Width
  • H: Section Height
  • R: Free Radius
  • R’: Loaded Radius
  • E: Distance Between Dual Tires
  • D: Free Diameter (R x 2)
  • Ø: Rim Diameter

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Load index is subject to the driving speed, tire structure, and tire mounting position (single or dual). The US TRA, Korea KS, EU ETRTO, and Japan JIS standards all follow the same load index.

Trucks & Buses

The table below shows the smallest index under cold tire conditions.

Speed Rating (km/h) Air PressureLoad
Bias Tire
Radial Tire
Standard Tire
Low Profile Tire
110-120+10PSI+5PSI-12%-12%
96-110+10PSI+5PSI-4%-4%
81-95
No IncreaseNo Increase 00
66-80
 No Increase No Increase +9% +7%
51-65
No IncreaseNo Increase+16%
+9%
31-50No Increase+10PSI+24%+12%
20-30No Increase+15PSI+32%+17%

Light Truck

The table below shows the smallest index under cold tire conditions.

Speed Rating (km/h)Air PressureLoad
110-120+10PSI10%
96-110+10PSI-
81-95No Increase-
66-80No Increase+9%
51-65No Increase+16%
31-50No Increase+24%
20-30No Increase+32%

Air pressure can be appropriately increased under the following conditions:

A. Increase speed and load requirements

B. For better handling

However, the increased air pressure should not exceed the specified maximum load, 20 psi, nor exceed the maximum load and air pressure required by the rim.

Over inflation will lead to tire blowout which affects driving safety and increases operating costs!

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Step 1

First, inspect the tire thoroughly to determine if it is repairable.

Step 2

If any damage is found, mark the position both inside and outside with a crayon.

Step 3

Remove the foreign object that caused the damage.

Step 4

Check if there is any hidden damage inside or outside with a puncture probe.

Step 5

Determine the damage angle from inside out with a drill bit.

Step 6

If the damage is greater than 25°, use the two part separation method to repair. If the diameter of the damage is within 15 mm, use an integral radial plug.

Step 7

Align the center of the repair material with the center of the damage, and draw a peripheral line 25 mm beyond the repair material as the buffing line.

Step 8

Spray the area with a rubber cleaner.

Step 9

When the tire is still wet, scrape off the foreign objects with a scraper.

Step 10

Use a rubber buffing wheel and a low-speed pneumatic buffing machine to buff the previously marked area.

Step 11

Use a carbide cutter and a low-speed pneumatic drill to cut along the damaged area from inside to outside in a clockwise direction for at least three times.

Step 12

Repeat step 11 from outside to inside for three times to make sure the damaged area is properly treated.

Step 13

Use a vacuum cleaner to remove the steel slag and scrap rubber on both sides of the tire.

Step 14

Use the rubber cleaner and a clean cloth to remove the contaminants by wiping the tire outward from the center. Repeat this step until the buffed area is completely clean. Wait 3-4 minutes for the cleaner to completely dry.

Step 15

With a brush, apply the curing agent both inside and outside the buffed hole.

Step 16

Apply the curing agent on the buffed area outward from the center, and wait 3-5 minutes for it to dry.

Step 17

Position the steel string puller around the middle of the exposed black rubber stem.

Step 18

Remove the blue film wrapping the rubber stem.

Step 19

Remove the blue film from the crown and reposition it (see picture). This is to avoid unnecessary adhesion during the pulling process and contamination of the grey cushion gum.

Step 20

Position the integral radial plug horizontally, and apply the curing agent on the cone part of the rubber stem and on the edge of the gray adhesive.

Step 21

Drill the steel string puller through the hole paying special attention to the alignment of the arrow with the tire toe.

Step 22

Pull the steel string puller from the inside out so that the integral radial plug is secured in place.

Step 23

After the rubber stem is pulled out of the hole, check if arrow 5 is aligned with the tire toe. Continue pulling until the reinforced crown is pressed against the inner tire surface.

Step 24

Use your thumb to press the crown into position.

Step 25

Use a compaction roller to secure the crown in place from the center out.

Step 26

Remove the blue film and repeat the step above until the crown is completely compacted.

Step 27

Remove the white film.

Step 28

Apply safety sealant to the crown and along the polished site, when tubeless tire is repaired.

Step 29

Cut the rubber stem so that it is leveled with the tread. If the rubber stem is in the groove, use a carving machine to carve it so that it matches the tread.

Step 30

The repair process is completed, and the tire can now be put back into service.

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Step 1

The tire and tube should be cleared of debris before assembly. It is recommended to apply dry and finely grounded talc or graphite powder uniformly on the surface of the tire inner wall, tube, and flap.

Step 2

When placing the folded tube into the tire, the valve stem must be face upwards. Unfold and flatten the inner tube when inserting it into the tire. Remove the tube valve cap.

Step 3

Check if the flap is assembled in the correct position. Set the flap on the tube valve stem, between the tube and the tire. Make sure there are no wrinkles or folds on the flap edge.

Step 4

Apply noncorrosive lubricants uniformly on the bead. Install the tire onto the rim, aligning the valve with the rim valve slot.

Step 5

Insert the ring (compression ring) into the groove.

Step 6

Make sure all the components are properly installed and match with each other. Remove the tube valve core and inflate the tire pressure to the recommended 350 kPa. Using a wooden mallet, tap along the tire circumference so that the tire fits tightly with the rim.

Step 7

Check to see if the tire is installed correctly. If not, deflate the tire and readjust the position of the tire and the rim.

Step 8

After the tire is assembled, check to see that each component is installed properly before inflating the tire. Then inflate the tire to the specified pressure level and measure with a pressure gauge.

Note:

  • A. Tires must be installed on specified rims. The rims cannot be deformed, rusted, non-circular, cracked, unevenly welded, loosed, or sharp-edged.
  • B. Only tires with the same specification, structure, brand, size, ply rating, and pattern can be installed on the same axle.
  • C. Install directional tire so that the rotation direction is consistent with the vehicle’s traveling direction.
  • D. When replacing new tires, it is recommended to replace all the tires on vehicle or at least on the same axle.
  • E. Use special tools or machinery to install and remove tube tires.
  • F. During tire inflation, the operator should not stand to the side of the tire.

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Step 1

Choose the correct rim size and model for your tire. It is recommended to replace the rim if there are damages or cracks.

Step 2

Clean the rim with clean cotton towels.

Step 3

Tighten the valve stem cap to prevent the valve from loosening and leaking air.

Step 4

Apply noncorrosive lubricants uniformly on the bead. Install the tire onto the rim by aligning the valve with the rim valve slot.

Step 5

Check if the tire is damaged or cracked. If so, replace or repair the tire immediately. Clean the tire (recommend using special tire cleaners) by wiping off the moisture or debris inside the tire with a clean cotton towel.

Step 6

Use lubricants to protect the tire from damage. Lubricate the bead and rim edge uniformly.

Step 7

Align the balance point (white dot) with the valve, tilt the tire to place it onto the rim, and fix the rim in place using splints.

Step 8

Insert the indenter from the bottom of the rim and rotate the main axle clockwise. Never install both beads at the same time to avoid bead damage.

Step 9

Inflate the tire to the recommended pressure of 350 kPa. Check to see if the tire is installed correctly (tire line matches up with rim edge). If not, deflate the tire and readjust the position of the tire and the rim.

Step 10

After the tire is assembled, check to see that each component is installed properly before inflating the tire. Then inflate the tire to the specified pressure level and measure with a pressure gauge. During tire inflation, the operator should not stand to the side of the tire.

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1. Tubeless Tire Features:

  • • Outer diameter of a tubeless tire is the same as a tube tire, so the gear ratio will not change before or after a tire change
  • • Rim diameter is 2 inches wider with better heat dissipation and lower temperatures
  • • Load capacity remains the same with a lighter rim

2. Advantages of Tubeless Tires: 10% Lighter Than Tube Tires


Lower sidewall for more accurate and safer steering and handling

Fewer components with lower friction and rolling resistance for better fuel efficiency

Superior heat dissipation and lower temperatures for longer tire life

Better contact area with uniform wear for longer tire life

Less components and lighter weight for reduced fuel consumption

3. Basic Components of a Tubeless Tire


Tubeless Tire (3 Basic Components)

For example, 12R22.5 18PR GAL817:


A: Casing = 64.21 kg
B: Rim and Valve = 47.55 kg
Total Weight: 111.76 kg

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Tube Tire Tubeless Tire
Bias Tire Radial Tire 90 Series 80 Series 75 Series 70 Series 65 Series
7.00-16 7.00R16 8R17.5 / 205/75R17.5 / /
7.50-16 7.50R16 8.5R17.5 / 215/75R17.5 / /
8.25-16 8.25R16 9.5R17.5 / 235/75R17.5 245/70R19.5 /
7.50-20 7.50R20 8R22.5 / / / /
8.25-20 8.25R20 9R22.5 / / / /
9.00-20 9.00R20 10R22.5 / / 255/70R22.5 /
10.00-20 10.00R20 11R22.5 275/80R22.5 295/75R22.5 275/70R22.5 /
11.00-20 11.00R20 12R22.5 295/80R22.5 / / 385/65R22.5
12.00-20 12.00R20 13R22.5 315/80R22.5 / 315/70R22.5 425/65R22.5
Disclaimer: This Specification Guidance Table for Replacement is only for reference. Giti does not assume any responsibility for it. When replacing tires, please consult with your local distributor and take into consideration the rim, tire specification, load, handling, and other factors.
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