When you put larger tyres on your Hilux, the gearing is altered. The following tables show the affect of fitting larger tyres to your vehicle on Engine RPM at 100 km/hr. There are a few different tables as the various transmission and engine combinations have different gearing ratios. The stock ratios are coloured in Yellow, The best match for a given tyre size are coloured in Green and ones that you can get away with are shown in Blue.

Diesel Auto (3.727:1 Diff ratio)

Difference
Tyre Size (inches) Stock 3.909 4.1 4.556 Stock 3.909 4.1 4.556
29 2,722 2,855 2,994 3,327
30 2,631 2,760 2,894 3,216 - 91 38 173 494
30.5 2,588 2,714 2,847 3,164 - 134 - 7 125 442
31 2,546 2,670 2,801 3,113 - 176 - 51 79 391
32 2,467 2,587 2,713 3,015 - 255 - 135 - 8 293
33 2,392 2,509 2,631 2,924 - 330 - 213 - 91 202
33.5 2,356 2,471 2,592 2,880 - 366 - 251 - 130 158
34 2,321 2,435 2,554 2,838 - 400 - 287 - 168 116
35 2,255 2,365 2,481 2,757 - 467 - 356 - 241 35

Petrol Auto (3.583:1 Diff ratio)

Difference
Tyre Size (inches) Stock 3.727 3.909 4.1 4.556 Stock 3.727 3.909 4.1 4.556
29 2,831 2,945 3,089 3,240 3,600
30 2,737 2,847 2,986 3,132 3,480 - 94 16 155 301 649
30.5 2,692 2,800 2,937 3,080 3,423 - 139 - 31 106 249 592
31 2,648 2,755 2,889 3,031 3,368 - 183 - 76 58 200 537
32 2,566 2,669 2,799 2,936 3,262 - 265 - 162 - 32 105 431
33 2,488 2,588 2,714 2,847 3,164 - 343 - 243 - 117 16 332
33.5 2,451 2,549 2,674 2,804 3,116 - 380 - 282 - 157 - 27 285
34 2,415 2,512 2,635 2,763 3,071 - 416 - 319 - 197 - 68 239
35 2,346 2,440 2,559 2,684 2,983 - 485 - 391 - 272 - 147 152

Petrol and Diesel Manual Transmission

Difference
Tyre Size (inches) Stock 3.727 3.909 4.1 4.556 Stock 3.727 3.909 4.1 4.556
29 2,581 2,684 2,707 2,839 3,155
30 2,495 2,495 2,616 2,744 3,049 - 86 - 86 36 164 469
30.5 2,454 2,454 2,573 2,699 2,999 - 127 - 127 - 7 119 419
31 2,414 2,414 2,532 2,656 2,951 - 166 - 166 - 49 75 370
32 2,339 2,339 2,453 2,573 2,859 - 242 - 242 - 128 - 8 278
33 2,268 2,268 2,379 2,495 2,772 - 313 - 313 - 202 - 86 192
33.5 2,234 2,234 2,343 2,457 2,731 - 347 - 347 - 238 - 123 150
34 2,201 2,201 2,309 2,421 2,691 - 379 - 379 - 272 - 159 110
35 2,138 2,138 2,243 2,352 2,614 - 442 - 442 - 338 - 228 33