Page 290 - Automotive Engineering Powertrain Chassis System and Vehicle Body

Tyres and wheels C HAPTER 10.1

Wheel load capacity in kg
Load with tyre pressure measured in bars
index 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5
69 215 225 240 250 260 270 285 295 305 315 325
70 225 235 245 260 270 280 290 300 315 325 335
71 230 240 255 265 275 290 300 310 325 335 345
72 235 250 260 275 285 295 310 320 330 345 355
73 245 255 270 280 295 305 315 330 340 355 365
74 250 260 275 290 300 315 325 340 350 365 375
75 255 270 285 300 310 325 335 350 360 375 387
76 265 280 295 310 320 335 350 360 375 385 400
77 275 290 305 315 330 345 360 370 385 400 412
78 280 295 310 325 340 355 370 385 400 410 425
79 290 305 320 335 350 365 380 395 410 425 437
80 300 315 330 345 360 375 390 405 420 435 450
81 305 325 340 355 370 385 400 415 430 445 462
82 315 330 350 365 380 395 415 430 445 460 475
83 325 340 360 375 390 405 425 440 455 470 487
84 330 350 365 385 400 420 435 450 470 485 500
85 340 360 380 395 415 430 450 465 480 500 515
86 350 370 390 410 425 445 460 480 495 515 530
87 360 380 400 420 440 455 475 490 510 525 545
88 370 390 410 430 450 470 485 505 525 540 560
89 385 405 425 445 465 485 505 525 545 560 580
90 400 420 440 460 480 500 520 540 560 580 600
91 410 430 450 475 495 515 535 555 575 595 615
92 420 440 465 485 505 525 550 570 590 610 630
93 430 455 475 500 520 545 565 585 610 630 650
94 445 470 490 515 540 560 585 605 625 650 670
95 460 485 505 530 555 575 600 625 645 670 690
96 470 495 520 545 570 595 620 640 665 685 710
97 485 510 535 560 585 610 635 660 685 705 730
98 500 525 550 575 600 625 650 675 700 725 750
99 515 540 570 595 620 650 675 700 725 750 775
100 530 560 590 615 640 670 695 720 750 775 800

Fig. 10.1-13 Load capacity/air pressure category specified in the directives. The load capacity on the left – also known as ‘load index’
(LI) – applies for all passenger cars up to the speed symbol W; they relate to the minimum load capacity values up to 160 km h 1 at tyre
pressure 2.5 bar (see Section 10.1.2.6). Further criteria, such as maximum speed, handling etc., are important for the tyre pressures to be
used on the vehicle. For LI values above 100, further load increases are in 25-kg increments:
LI ¼ 101 corresponds to 825 kg,
LI ¼ 102 corresponds to 850 kg etc. to
LI ¼ 108 corresponds to 1000 kg.
followed by information on the carcass strength (6, 8 or The 185 R 14 tyre is passenger car size, which is also
10 PR) used to indicate suitability for use on light com- fitted to light commercial vehicles.
mercial vehicles, or the word ‘reinforced’ simply
appeared at the end of the marking. The current marking 10.1.2.5.4 Tyre dimensions
(as for passenger cars) retains the speed symbol as well as Figure 10.1-15 shows the important data for determining
the load index which, behind the slash, gives the reduced tyre size:
load capacity on twin tyres. Compared with the previous
size marking;
marking, the new system is as follows:
authorized rims and measuring rim;
tyre dimensions: width and outside diameter new
Former Current and maximum during running;
static rolling radius (Fig. 10.1-11);
– 205/65 R 15 98 S (Fig. 10.1-15) rolling circumference (at 60 km h , Fig 10.1-16, see
1
185 SR 14 185 R 14 90 S also Section 10.1.2.8);
185 SR 14 reinforced 185 R 14 94 R load capacity coefficient (load index LI, Fig. 10.1-13);
185 R 14 C 6 PR 185 R 14 99/97 M tyre load capacity at 2.5 bar and up to 160 km h 1
185 R 14 C 8 PR 185 R 14 102/100 M
(see Section 10.1.2.6).

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