Gear ratio
3.42 3.73 4.10
Tire diameter
 28 1857 2025 2226 2476
28.5 1824 1989 2187 2432
29 1793 1955 2149 2390
29.5 1762 1922 2113 2350
30 1733 1890 2077 2310
30.5 1704 1859 2043 2273
31 1677 1829 2010 2236
31.5 1650 1800 1978 2200
32 1625 1772 1948 2166
32.5 1600 1745 1918 2133
33 1575 1718 1889 2100
33.5 1552 1692 1860 2069
34 1529 1668 1833 2039
34.5 1507 1643 1806 2009
35 1485 1620 1781 1980
35.5 1464 1597 1756 1953
36 1444 1575 1731 1925
36.5 1424 1553 1707 1899
37 1405 1532 1684 1873
37.5 1386 1512 1662 1848
38 1368 1492 1640 1824
38.5 1350 1473 1619 1800
39 1333 1454 1598 1777
39.5 1316 1435 1578 1755
40 1300 1417 1558 1733
4Lo 1st 2nd 3rd OD
mph

The information on this page is for the 2002-2009 Chevy Trailblazer and GMC Envoy with a 4L60-E transmission. Red values indicate highway RPMS that are too low. Values in the pink range will require transmission coolers at a minimum to prevent overheating at highway speeds.

Increased  power
Standard  duty
Fuel  economy
Drivetrain  overload