Gearing Calculator
Theoretical gearing speed only — what the gearing allows, not what the car will do. Top gear is usually limited by power and drag, not ratio. No tire growth at speed, no driveline slip.
Gears
spread 4.22 : 1| Gear | Ratio | Overall | Max mph | Lands at | Drop | Drop % |
|---|---|---|---|---|---|---|
| 1st | 2.66 | 9.92 | 52.2 | — | — | — |
| 2nd | 1.78 | 6.64 | 78.1 | 4,684 | −2,316 | −33.1% |
| 3rd | 1.30 | 4.85 | 106.9 | 5,112 | −1,888 | −27.0% |
| 4th | 1.00 | 3.73 | 139.0 | 5,385 | −1,615 | −23.1% |
| 5th | 0.80 | 2.98 | 173.7 | 5,600 | −1,400 | −20.0% |
| 6th | 0.63 | 2.35 | 220.6 | 5,513 | −1,488 | −21.3% |
Shift drop depends only on the two gearbox ratios — final drive, dropgear, and tire are constant across gears and cancel out. A different ring-and-pinion moves every speed in this table and changes none of the drops.
Engine RPM vs road speed
78.2 in rolling · 3.73 finalTire
size formattirerack.com/upgrade-garage/racing-and-rally-motorsport-tire-size-formats
Transmission
Aftermarket box, distinct from the OEM T56 above.
sourcetxdrivetrain.com/tremec-t56-transmissions-differences-explained; tremec-blog.com/tremec-magnum-transmission-gear-ratio-options (2026-08-04)
Final drive
Tooth counts work too — 41/9 is 4.556 : 1.
Engine
Preset ratios are verified and cited per record, above. Curated, not comprehensive — check yours before ordering a gearset.