Technical Information at Sumitomo Tires

Drive axle alignment

Drive axle alignment is very important. Tandem drive axles that are not parallel to each other have a definite effect on steer-tire wear. Fig. 1 shows a model of a tandem-drive axle tractor with both drive axles in proper alignment. In this case, the driver simply steers the truck straight ahead and neither fast wear nor irregular wear would be expected as a result of the driving axles.

A more severe case is shown in Fig. 2. Here, the drive axles are neither parallel to each other nor perpendicular to the chassis centerline. The drive axle tires are trying to force the vehicle to turn left and the driver must compensate by turning to the right. This will result in fast and irregular wear and, as recent tests have shown, in a much more severe way then the previous case. Tests also indicate that the steer tire on the same side of the truck, on which the drive tires are closest together, will wear into an out-of-round condition.

Figure 1

Figure 2

Vehicle Alignment

For best vehicle handling and tire life, proper vehicle alignment is required. For best readings on alignment settings, vehicle should be loaded. However, many vehicle manufacturers also have tolerances for alignment settings when vehicle is unloaded. Before starting, correct any air pressure differences in tires and make sure vehicle is on a level surface, with brakes off.

FRONT AXLE RECOMMENDATIONS

TOE IN
Toe-in-set close to zero as vehicle manufacturer's recommendations allow in loaded condition. Do not set beyond zero as a toe-out condition will develop.

CASTER
Caster-set to the maximum positive setting, which the vehicle manufacturer's recommendations allow.

CAMBER
Camber-set as close to zero degrees as the vehicle manufacturer's recommendations allow in loaded condition.

DRIVE AXLE RECOMMENDATIONS

Irregular wear patterns on steer axle tires may come from misaligned drive axles and trailer axles, not to mention the obvious loss of tire mileage, vehicle handling, and fuel economy. Drive and trailer axle alignment is normally set before steer axle corrections are made.

Drive axles should be aligned in the following manner:

Position the drive axles perpendicular to the chassis center line.
For tandem drives, the drive axles should be positioned parallel to one another.

Trailer axles should be aligned to the center line of trailer pin at the start of settings.

Position axles to be perpendicular to the trailer center line and parallel to each other.

Sumitomo Range of Sizes (by Load Range)

TIRESIZE	ST758	ST738	ST718	ST928	ST908	ST918	ST727	ST717	ST710
8.25R15	----	----	----	----	----	----	G	----	----
10.00R15	----	----	----	----	----	----	G	----	----
9R17.5	----	----	----	----	----	----	----	G	----
10R17.5	----	----	----	----	----	----	H	----	----
11R17.5	----	----	----	----	----	----	----	G	----
215/75R17.5	----	----	----	----	----	----	H	----	----
8R19.5	----	----	F	----	----	----	----	----	----
225/70R19.5	----	----	F	----	----	F	----	----	----
245/70R19.5	----	----	F	----	----	G	----	----	----
8.25R20	----	----	----	----	----	----	G	----	----
9.00R20	----	----	----	----	----	----	F	----	----
10.00R20	----	G	----	----	G,H	----	G, H	----	----
11.00R20	----	----	----	----	----	----	H	----	----
12.00R20	----	----	----	----	----	----	J	----	----
13/80R20	----	----	----	----	----	----	----	J	----
14/80R20	----	----	----	----	----	----	----	J	----
11.00R22	----	----	----	----	----	----	----	----	----
10R22.5	----	----	----	----	----	----	G	----	----
11R22.5	H	H	----	H	H	----	H	----	H
12R22.5	----	H	----	----	H	----	H	----	----
11R24.5	H	H	----	H	H	----	H	----	H
245/75R22.5	----	----	G	----	----	----	----	----	----
255/70R22.5	----	----	----	----	H	----	H	----	----
295/75R22.5	G	G	----	G	G	----	----	----	G
285/75R24.5	G	G	----	G	G	----	----	----	G
315/80R22.5	----	----	J	----	----	----	----	----	----
385/65R22.5	----	----	----	----	----	----	----	----	----
425/65R22.5	----	----	----	----	----	----	----	----	----
445/65R22.5	----	----	----	----	----	----	----	----	----

TIRESIZE	ST700	ST900	ST901	ST518	ST528	ST508	ST770	ST520	ST720	ST510
8.25R15	----	----	----	----	----	----	----	----	----	----
10.00R15	----	----	----	----	----	----	----	----	----	----
9R17.5	----	----	----	----	----	----	----	----	----	----
10R17.5	----	----	----	----	----	----	----	----	----	----
11R17.5	----	----	----	----	----	----	----	----	----	----
215/75R17.5	----	----	----	----	----	----	----	----	----	----
8R19.5	----	----	----	----	----	----	----	----	----	----
225/70R19.5	----	----	----	----	----	----	----	----	----	----
245/70R19.5	----	----	----	----	----	----	----	----	----	----
8.25R20	----	----	----	----	----	----	----	----	----	----
9.00R20	----	----	----	----	----	----	----	----	----	----
10.00R20	----	H	----	H	----	----	----	----	----	----
11.00R20	----	----	----	H	----	----	----	----	----	----
12.00R20	----	----	----	----	----	J	----	----	----	----
13/80R20	----	----	----	----	----	----	----	----	----	----
14/80R20	----	----	----	----	----	----	----	----	----	----
11.00R22	----	----	----	----	----	H	----	----	----	----
10R22.5	----	----	----	----	----	----	----	----	----	----
11R22.5	H	H	----	H	H	----	----	----	----	----
12R22.5	----	H	---	H	----	----	----	----	----	----
11R24.5	H	H	H	H	H	----	----	----	----	----
245/75R22.5	----	----	----	----	----	----	----	----	----	----
255/70R22.5	----	----	----	----	----	----	----	----	----	----
295/75R22.5	G	----	----	----	----	----	----	----	----	----
285/75R24.5	G	----	----	----	----	----	----	----	----	----
315/80R22.5	----	----	L*	----	L*	----	----	----	----	----
385/65R22.5	----	----	----	----	----	----	J	J	J	----
425/65R22.5	----	----	----	----	----	----	---	L	L	L
445/65R22.5	----	----	----	----	----	----	---	L	L	----

Recommendations for Long Tire Life

Inspect tire conditions regularly. Look for signs of sidewall bulges, cracking, cuts and stone retention in grooves. If you have a question or concern, consult your Sumitomo Tire dealer.

Tire Replacement
By Department of Transportation regulations, any trailer or drive axle tire is to be removed from service when there are only 2/32nds of tread left (or 4/32nds on steer axle tires) in any tread groove. Sumitomo advises that, as a rule of thumb, tires should be removed at 4/32nds remaining tread to allow better casing recovery for retreading.

Proper Tire Inflation
It is advisable to check all tire inflation pressures before each trip, or at least weekly. The best time to obtain accurate readings is when tires are cool to the touch, before any distance is traveled. Consult the air pressure guidelines in this book, refer to the tire sidewall, or pressure charts from the Tire and Rim Association. When speeds are constantly above 70 m.p.h., it is recommended to use maximum air pressure for good wear and performance. For safety and ease of checking air pressure, metal flow-through valve caps should be used.

Tire Rotation
Because of vehicle specifications (wheelbase, horsepower, gears, suspension) and terrain, most tires used on drive axles wear faster on the rear drive axle than on the front drive axle. By cross rotating rear axle tires to front axle, and front axle tires moved to rear axle position, wear can be equally controlled on all drive positions, resulting in longer miles in service.

Practice Good Driving Habits

Avoid fast starts and sudden stops.
Avoid using only trailer brakes to slow vehicle.
Avoid potholes and debris (safely) if possible.
Beware of curb location and avoid scuffing sidewall.
Observe a safe speed limit, using posted speeds as guidelines.

TIRESIZE	SD	UNITS	PSI 65	PSI 70	PSI 75	PSI 80	PSI 85	PSI 90	PSI 95
225/70R19.5	D	lb	2600	2720	2860	3000	3115	3245	3415
225/70R19.5	S	lb	2755	2895	3040	3195	3315	3450	3640
245/70R19.5	D	lb				3415	3515	3655	3860
245/70R19.5	S	lb				3640	3740	3890	4080
9R22.5	D	lb		3270	3410	3550	3690	3860	4005
9R22.5	S	lb		3370	3560	3730	3890	4080	4235
10R22.5	D	lb		3860	4045	4230	4410	4585	4760
10R22.5	S	lb		4080	4280	4480	4675	4850	5025
11R22.5	D	lb		4380	4580	4760	4950	5205	5415
11R22.5	S	lb		4530	4770	4990	5220	5510	5730
12R22.5	D	lb		4780	4990	5190	5390	5675	5785
12R22.5	S	lb		4940	5200	5450	5690	6005	6205
255/70R22.5	D	lb				3970	4110	4275	4410
255/70R22.5	S	lb				4190	4370	4550	4675
295/75R22.5	D	lb		4095	4300	4540	4690	4885	5070(F)
295/75R22.5	S	lb		4500	4725	4940	5155	5370	5510(F)
315/80R22.5	D	lb					6435	6675	7020
315/80R22.5	S	lb					5530	5780	6055
385/65R22.5	S	lb		6389	6720	6940	7350	7650	8050
425/65R22.5	D	lb		7590	7990	8270	8740	9100	9370
445/65R22.5	D	lb		8230	8660	9090	9480	9870	10200
11R24.5	D	lb		4660	4870	5070	5260	5510	5675
11R24.5	S	lb		4820	5070	5310	5550	5840	6095
285/75R24.5	D	lb		4135	4340	4540	4740	4930	5205(F)
285/75R24.5	S	lb		4545	4770	4940	5210	5420	5675(F)
9.00R20	D	lb		3860	4045	4230	4410	4585	4760
9.00R20	S	lb		4080	4280	4480	4675	4850	5025
10.00R20	D	lb		4380	4580	4760	4950	5205	5415
10.00R20	S	lb		4530	4770	4990	5220	5510	5730
11.00R20	D	lb		4780	4990	5190	5390	5675	5785
11.00R20	S	lb		4940	5200	5450	5690	6005	6205
11.00R22	D	lb		5080	5300	5520	5730	5840	6095
11.00R22	S	lb		5240	5520	5790	6040	6395	6650

TIRESIZE	SD	UNITS	PSI 100	PSI 105	PSI 110	PSI 115	PSI 120	PSI 125	PSI 130
225/70R19.5	D	lb	3490	3615	3750(G)
225/70R19.5	S	lb	3715	3845	3970(G)
245/70R19.5	D	lb	3940	4075	4300(G)
245/70R19.5	S	lb	4190	4335	4540(G)
9R22.5	D	lb	4150	4300(F)
9R22.5	S	lb	4390	4540(F)
10R22.5	D	lb	4940	5075	5210	5355(G)
10R22.5	S	lb	5205	5360	5515	5675(G)
11R22.5	D	lb	5625	5840(G)	5895	5950	6005(H)
11R22.5	S	lb	5950	6175(G)	6230	6465	6610(H)
12R22.5	D	lb	5895	6005	6265	6525	6580(H)
12R22.5	S	lb	6405	6610	6870	7130	7390(H)
255/70R22.5	D	lb	4455	4610	4675	4915	5070(H)
255/70R22.5	S	lb	4895	5065	5205	5400	5510(H)
295/75R22.5	D	lb	5260	5440	5675(G)	5795	6005(H)
295/75R22.5	S	lb	5780	5980	6175(G)	6370	6610(H)
315/80R22.5	D	lb	7310	7630	7950	8270	8485	8750	9000(L)
315/80R22.5	S	lb	6330	6605	6885	7160	7635	7893	8255(L)
385/65R22.5	S	lb	8230	8510	8820	9050	9370(J)
425/65R22.5	D	lb	9790	10100	10500	10700	11000(L)
445/65R22.5	D	lb	10600	11000	11400	11700	12300(L)
11R24.5	D	lb	5840	6005	6265(G)	6525	6780(H)
11R24.5	S	lb	6350	6610	6790(G)	6970	7160(H)
285/75R24.5	D	lb	5310	5495	5675(G)	5860	6175(H)
285/75R24.5	S	lb	5835	6040	6175(G)	6440	6780(H)
9.00R20	D	lb	4940(F)
9.00R20	S	lb	5205(F)
10.00R20	D	lb	5625	5840(G)	5895	5950	6005(H)
10.00R20	S	lb	5950	6175(G)	6320	6465	6610(H)
11.00R20	D	lb	5895	6005	6265	6525	6780(H)
11.00R20	S	lb	6405	6610	6870	7130	7390(H)
11.00R22	D	lb	6350	6610	6790	6970	7160(H)
11.00R22	S	lb	6910	7160	7380	7600	7830(H)

LOAD RANGE /PLY TABLE
B	-	4
C	-	6
D	-	8
E	-	10
F	-	12
G	-	14
H	-	16
J	-	18
L	-	20
M	-	22

SPEED SYMBOL
Speed Symbol		Speed MPH
B	-	30
C	-	35
D	-	40
E	-	43
F	-	50
G	-	55
J	-	62
K	-	68
L	-	75
M	-	81
N	-	87

LI	LBS
90	1,325
91	1,355
92	1,390
93	1,435
94	1,475
95	1,520
96	1,565
97	1,610
98	1,655
99	1,710
100	1,765
101	1,820
102	1,875
103	1,930
104	1,985

LI	LBS
105	2,040
106	2,095
107	2,150
108	2,205
109	2,270
110	2,335
111	2,405
112	2,470
113	2,535
114	2,600
115	2,680
116	2,755
117	2,835
118	2,910
119	3,000

LI	LBS
120	3,085
121	3,195
122	3,305
123	3,515
124	3,525
125	3,640
126	3,750
127	3,860
128	3,970
129	4,080
130	4,190
131	4,300
132	4,410
133	4,540
134	4,675

LI	LBS
135	4,805
136	4,940
137	5,070
138	5,205
139	5,355
140	5,510
141	5,695
142	5,840
143	6,005
144	6,175
145	6,395
146	6,610
147	6,780
148	6,940
149	7,150

LI	LBS
150	7,390
151	7,610
152	7,830
153	8,050
154	8,270
155	8,540
156	8,820
157	9,090
158	9,370
159	9,650
160	9,920
161	10,200
162	10,500
163	10,700
164	11,000

LI	LBS
165	11,400
166	11,700
167	12,000
168	12,300
169	12,800
170	13,200

Determining Correct Air Pressure

A tire requires proper air pressure to adequately carry the load placed on it. The tires also provide traction for braking and steering.

Since the loaded vehicle weight determines tire inflation pressure, all tire manufacturers offer a load/inflation table to help determine the proper pressure. These tables reflect values taken from the Tire and Rim Association. In general, use these steps to determine correct air pressure:

Always check air pressure when ambient temperature is cold.
Confirm if tire will be used in a single or dual wheel position.
In either case, determine the total weight that is allowed on the axle. In the case of a STEER axle (using two tires) divide the value by two.
Compare this value with the above load inflation table, and use the corresponding air pressure.

Also consider operating speeds. Many tire manufacturers recommend maximum speeds for various tire applications. Consult your Sumitomo representative if you have questions.

Sumitomo has added the above symbols and values to many of its tires. These are to be used when purchasing not only the correct tread design, but the proper size and ply rating suitable for your operation.

The above SPEED SYMBOL indicates the speed that the tire can carry a load corresponding to its load index under normal service conditions suggested by Sumitomo.

The above LOAD INDEX is a code which reflects the maximum load a tire can carry at the speed indicated by its SPEED SYMBOL, based on the service application suggested by Sumitomo.