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Engine RPM Gear Ratio Calculator-Calculate Engine RPM from Speed, Tire Size, Gear Ratios, and Transmission

Transmisison Gear Ratio Chart

Transmission 1st 2nd 3rd 4th 5th 6th
GM TH200-4R 2.74 1.57 1.00 0.67    
GM TH350 2.52 1.52 1.00      
GM TH400 2.48 1.48 1.00      
GM TH700R4 3.06 1.63 1.00 0.70    
GM 4L60/4L60E 3.06 1.63 1.00 0.70    
GM 4L80/4L80E 2.48 1.48 1.00 0.75    
GM 5L40 3.46 2.21 1.59 1.00 0.76  
GM 5L50 3.45 2.21 1.59 1.00 0.76  
GM 6L80 4.03 2.36 1.53 1.15 0.85 0.67
GM ALLISON 1000 (5 SPEED) 3.10 1.81 1.41 1.00 0.71  
GM ALLISON 1000 (6 SPEED) 3.10 1.81 1.41 1.00 0.71 0.62
DODGE TF727 2.45 1.45 1.00      
DODGE TF904 2.74 1.54 1.00      
DODGE TF 909 2.74 1.54 1.00      
DODGE TF 999 2.74 1.54 1.00      
DODGE 30RH 2.74 1.54 1.00      
DODGE 32RE 2.74 1.54 1.00      
DODGE 32RH 2.74 1.54 1.00      
DDOGE 42RE 2.74 1.54 1.00 0.69    
DODGE 42RLE 2.84 1.57 1.00 0.69    
DODGE 44RE 2.74 1.54 1.00 0.69    
DODGE 45RFE 3.00 1.67 1.00 0.75    
DODGE 46RE 2.45 1.45 1.00 0.69    
DODGE 47RE 2.45 1.45 1.00 0.69    
DODGE 48RE 2.45 1.45 1.00 0.69    
DODGE 545RFE (’03-’05) 3.00 1.67 1.00 0.75 0.67  
DODGE 545RFE (’06 & UP) 3.00 1.67 1.00 0.75 0.67  
DODGE 68RFE 3.23 1.83 1.41 1.00 0.81 0.62
DODGE G56 (’05-’07) 6.29 3.48 2.10 1.38 1.00 0.79
DODGE G56 (’08 & UP) 5.94 3.28 1.98 1.31 1.00 0.74
DODGE NAG1 3.59 2.19 1.41 1.00 0.83  
FORD C4 2.46 1.46 1.00      
FORD C5 2.46 1.46 1.00      
FORD C6 2.46 1.46 1.00      
FORD 4R44E 2.47 1.47 1.00 0.75    
FORD 4R55E 2.47 1.47 1.00 0.75    
FORD 4R70E 2.84 1.55 1.00 0.70    
FORD 4R70W 2.84 1.55 1.00 0.70    
FORD 4R75E 2.84 1.55 1.00 0.70    
FORD 4R75W 2.84 1.55 1.00 0.70    
FORD 4R100 2.71 1.54 1.00 0.71    
FORD 5R55E 2.47 1.87 1.47 1.00 0.75  
FORD 5R55N 3.25 2.44 1.55 1.00 0.75  
FORD 5R55S 3.22 2.29 1.55 1.00 0.71  
FORD 5R55W 3.22 2.41 1.55 1.00 0.75  
FORD 5R110 3.09 2.20 1.54 1.00 0.71  
FORD 5R110W 3.09 2.20 1.54 1.00 0.71  
FORD 6HP26 4.17 2.34 1.52 1.14 0.87 0.69
FORD 6R60 4.17 2.34 1.52 1.14 0.87 0.69
FORD A4LD 2.47 1.47 1.00 0.75    
FORD A4LDE 2.47 1.47 1.00 0.75    
FORD A5LDE 2.47 1.87 1.47 1.00 0.75  
FORD AOD 2.40 1.47 1.00 0.67    
FORD AOD-E 2.40 1.47 1.00 0.67    
FORD AODE 2.84 1.55 1.00 0.70    
FORD AODEW 2.84 1.55 1.00 0.70    
FORD AXOD-E 2.77 1.54 1.00 0.69    
FORD E4OD 2.71 1.54 1.00 0.71    
FORD TORQSHIFT 3.11 2.22 1.55 1.10 1.00 0.71
FORD M1HD 3.38 2.06 1.30 1.00 0.79  
FORD M5HD 4.11 2.37 1.42 1.00 0.77  
FORD M5HD-W 5.72 2.94 1.61 1.00 0.76  
FORD M5R2 3.75 2.32 1.43 1.00 0.75  
FORD M5R2-C 3.42 2.16 1.34 1.00 0.75  
FORD M6HD-6 5.79 3.31 2.10 1.31 1.00 0.72
FORD M50D (2.3) 3.97 2.34 1.46 1.00 0.79  
FORD M50D (5.0) 3.35 1.93 1.29 1.00 0.79  
FORD M50D-R1 (2.3/3.0) 3.72 2.20 1.50 1.00 0.79  
FORD M50D-R1 (4.0) 3.40 2.05 1.31 1.00 0.79  
FORD M50D-R2 3.91 2.24 1.49 1.00 0.80  
FORD M50D-R4 3.38 2.06 1.30 1.00 0.79  
FORD RICARDO 6 2.61 1.71 1.23 0.94 0.77 0.63
FORD T45 3.37 1.99 1.33 1.00 0.67  
FORD T5OD (’92-’98) 3.35 1.93 1.29 1.00 0.78  
FORD T5OD (’99-’05) 3.35 1.99 1.33 1.00 0.68  
GEO TRACKER 3.65 1.95 1.37 1.00 0.86  
LAND ROVER R380 3.69 2.13 1.40 1.00 0.77  
LAND ROVER R380 (’94-’97 DISCO, ’94-’95 D90) 3.32 2.13 1.39 1.00 0.73  
NISSAN PATROL (5SP MANUAL) 4.56 2.63 1.52 1.00 0.84  
NISSAN PATROL (4SP AUTO) 2.78 1.54 1.42 1.00    
SUZUKI SAMURAI (’89 & DOWN) 3.65 1.95 1.42 1.00 0.80  
SUZUKI SAMURAI (’90 & UP) 3.65 1.95 1.42 1.00 0.87  
SUZUKI SIDEKICK (3SP AUTO) 2.40 1.47 1.00      
SUZUKI SIDEKICK (4SP AUTO) 2.83 1.49 1.00 0.73    
SUZUKI SIDEKICK (5SP MANUAL) 3.65 1.95 1.38 1.00 0.86  
TOYOTA A43D 2.45 1.45 1.00 0.69    
TOYOTA A44D 2.83 1.49 1.00 0.69    
TOYOTA A340E 2.80 1.53 1.00 0.71    
TOYOTA A340F 2.80 1.53 1.00 0.71    
TOYOTA A340H 2.80 1.53 1.00 0.71    
TOYOTA A343F 2.80 1.53 1.00 0.75    
TOYOTA A440F 2.95 1.53 1.00 0.72    
TOYOTA A750E 3.52 2.04 1.40 1.00 0.72  
TOYOTA A750F 3.52 2.04 1.40 1.00 0.72  
TOYOTA U140E 3.94 2.19 1.41 1.02    
TOYOTA U140F 3.94 2.19 1.41 1.02    
TOYOTA C50 3.55 1.90 1.31 0.97 0.82  
TOYOTA C52 3.17 1.90 1.31 0.97 0.82  
TOYOTA C56 3.17 1.90 1.39 1.03 0.82  
TOYOTA C59 3.17 1.90 1.31 0.97 0.82  
TOYOTA C60 3.17 2.05 1.48 1.17 0.92 0.73
TOYOTA C65M 3.17 1.90 1.39 1.03 0.82 0.73
TOYOTA C150 3.55 1.90 1.31 0.97 0.82  
TOYOTA C151 3.55 1.90 1.23 0.89 0.73  
TOYOTA E153 3.23 1.91 1.26 0.92 0.73  
TOYOTA E350 3.54 2.05 1.33 0.97 0.73  
TOYOTA E351 3.54 2.05 1.33 0.97 0.73  
TOYOTA G40 3.93 2.33 1.91 1.00    
TOYOTA G52 3.93 2.33 1.45 1.00 0.85  
TOYOTA G54 4.45 2.40 1.41 1.00 0.80  
TOYOTA G57 3.70 2.02 1.37 1.00 0.85  
TOYOTA G58 3.93 2.14 1.40 1.00 0.85  
TOYOTA H41 5.30 2.84 1.63 1.00    
TOYOTA H42 3.56 2.29 1.41 1.00    
TOYOTA H55F 4.84 2.62 1.52 1.00 0.85  
TOYOTA J30 2.76 1.69 1.00      
TOYOTA R150 3.83 2.06 1.44 1.00 0.84  
TOYOTA R150F 3.83 2.06 1.44 1.00 0.84  
TOYOTA R151F 4.31 2.74 1.93 1.00 0.83  
TOYOTA RA60 4.17 2.19 1.49 1.19 1.00 0.85
TOYOTA RA60F 4.17 2.19 1.49 1.19 1.00 0.85
TOYOTA RA61F 4.17 2.19 1.49 1.19 1.00 0.85
TOYOTA S51 3.54 1.96 1.25 0.95 0.73  
TOYOTA S54 3.29 1.96 1.32 1.03 0.82  
TOYOTA V160 3.83 2.36 1.69 1.31 1.00 0.79
TOYOTA W46 3.95 2.14 1.38 1.00    
TOYOTA W55 3.57 2.06 1.38 1.00 0.85  
TOYOTA W56 3.95 2.14 1.38 1.00 0.85  
TOYOTA W58 3.29 1.89 1.28 1.00 0.78  
TOYOTA W59 3.95 2.14 1.38 1.00 0.85  
AISIN AR5 3.75 2.26 1.37 1.00 0.73  
AISIN WARNER AW30-40 2.80 1.55 1.00 0.75    
AISIN WARNER AW4 2.80 1.53 1.00 0.75    
AISIN WARNER AX-4 3.93 2.33 1.45 1.00    
AISIN WARNER AX-5 3.93 2.33 1.45 1.00 0.85  
AISIN WARNER AX-15 3.83 2.33 1.44 1.00 0.79  
ALLISON 545 3.45 2.25 1.41 1.00    
ALLISON 1000 (5 SPEED) 3.10 1.81 1.41 1.00 0.71  
ALLISON 1000 (6 SPEED) 3.10 1.81 1.41 1.00 0.71 0.62
BORG WARNER AS-8 2.40 1.46 1.00      
BORG WARNER SR4 4.07 2.39 1.49 1.00    
BORG WRNER T4 4.03 2.37 1.50 1.00    
BORG WARNER T5 4.03 2.37 1.50 1.00 0.86  
EATON-FULLER FS-4205A 8.05 4.35 2.45 1.48 1.00  
EATON-FULLER FS-4205B 6.99 3.78 2.13 1.28 1.00  
EATON-FULLER FS-6305A 7.22 3.89 2.22 1.39 1.00  
EATON-FULLER FS-6305B 7.22 3.89 2.22 1.27 1.00  
EATON-FULLER FS-5406A 9.01 5.27 3.22 2.04 1.36 1.00
EATON-FULLER FS-5406B 9.01 5.27 3.22 2.04 1.36 1.00
EATON-FULLER FSO-6406A 7.05 4.13 2.52 1.59 1.00 0.78
EATON-FULLER FSO-8406A 7.05 4.13 2.52 1.59 1.00 0.78
GETRAG 238 4.23 2.53 1.67 1.23 1.00 0.79
GETRAG 260 3.83 2.19 1.40 1.00 0.81  
GETRAG 260 (’03-’04 CTS ONLY) 3.57 2.04 1.34 1.00 0.82  
GETRAG 360 5.53 3.02 1.60 1.00 0.77  
GETRAG F234 3.58 2.02 1.35 0.98 0.69  
MUNCIE SN420 7.05 3.58 1.70 1.00    
MUNCIE SM465 6.56 3.58 1.70 1.00    
MITSUBISHI FM156 3.72 2.20 1.50 1.00 0.79  
NP260 3.09 1.67 1.00 0.73    
NP435 CLOSE RATIO 4.78 2.39 1.37 1.00    
NP435 WIDE RATIO 6.69 3.34 1.79 1.00    
NSG370 CLOSE RATIO 4.46 2.61 1.72 1.25 1.00 0.84
NSG370 WIDE RATIO 5.01 2.83 1.79 1.26 1.00 0.83
NV1500 3.96 2.37 1.49 1.00 0.83  
NV2550 3.85 2.25 1.48 1.00 0.75  
NV3500 CLOSE RATIO 3.50 2.14 1.39 1.00 0.73  
NV3500 WIDE RATIO 4.01 2.33 1.39 1.00 0.73  
NV3500HD 3.50 2.14 1.39 1.00 0.73  
NV3550 CLOSE RATIO 3.50 2.14 1.39 1.00 0.73  
NV3550 WIDE RATIO 4.01 2.33 1.39 1.00 0.73  
NV4500 (’93-’94 GM) 6.34 3.34 1.71 1.00 0.73  
NV4500 5.61 3.04 1.67 1.00 0.75  
NV4500HD 2.61 3.04 1.67 1.00 0.75  
NV5600 5.63 3.33 2.04 1.39 1.00 0.73
PEUGEOT BA-10 3.39 2.33 1.44 1.00 0.79  
SPICER 3053/3053A 5.02 2.78 1.62 1.00 0.79  
TREMEC 109MM 5.81 2.94 1.61 1.00 0.77  
TREMEC T-5 CLOSE RATIO 3.50 2.14 1.39 1.00 0.73  
TREMEC T-5 MEDIUM RATIO 3.76 2.18 1.42 1.00 0.72  
TREMEC T-5 WIDE RATIO 4.03 2.73 1.49 1.00 0.72  
TREMEC T56 CLOSE RATIO 2.66 1.78 1.30 0.74 0.50  
TREMEC T56 WIDE RATIO 2.90 2.07 1.43 1.00 0.84 0.57
TREMEC T150 2.99 1.75 1.00      
TREMEC T176 3.52 2.27 1.46 1.00    
TREMEC T177 3.82 2.29 1.46 1.00    
TREMEC T178 3.00 2.08 1.47 1.00    
TR -3450 3.82 2.31 1.42 1.00 0.83  
TR-3650 CLOSE RATIO 3.38 2.00 1.31 1.00 0.67  
TR-3650 WIDE RATIO 3.77 2.00 1.31 1.00 0.67  
TR-4050 CLOSE RATIO 5.81 2.94 1.61 1.00 0.77  
TR-4050 WIDE RATIO 6.16 3.11 1.71 1.00 0.76  
WARNER T14 3.10 2.60 1.00      
WARNER T15 3.00 1.83 1.00      
WARNER T18 4.02 3.09 1.69 1.00    
WARNER T18A 6.32 3.09 1.69 1.00    
WARNER T19 CLOSE RATIO 4.00 2.40 1.40 1.00    
WARNER T19 MEDIUM RATIO 5.11 3.03 1.79 1.00    
WARNER T19 WIDE RATIO 6.32 3.09 1.69 1.00    
WARNER T84 2.94 1.94 1.00      
WARNER T85 3.17 1.92 1.00      
WARNER T86 2.80 1.69 1.00      
WARNER T90 (JEEP CJ) 2.98 1.66 1.00      
WARNER T90 (PICKUP) 3.44 1.85 1.00      
WARNER T98 6.40 3.09 1.69 1.00    
ZF S5-42 CLOSE RATIO 4.65 2.60 1.53 1.00 0.77  
ZF S5-42 WIDE RATIO 5.72 2.94 1.61 1.00 0.76  
ZF S5-47 CLOSE RATIO 4.14 2.37 1.42 1.00 0.77  
ZF S5-47 MEDIUM RATIO 5.08 2.61 1.53 1.00 0.77  
ZF S5-47 WIDE RATIO 5.72 2.94 1.61 1.00 0.76  
ZF S6-40 2.64 1.80 1.29 1.00 0.75 0.49
ZF S6-650 5.79 3.30 2.10 1.31 1.00 0.72

1. What is Transmission Gear Ratio?

The transmission gear ratio refers to the ratio of the rotational speeds of different gears in a transmission. It determines the relationship between the engine's RPM (Revolutions Per Minute) and the wheel's rotation speed. For example:

  • 1st Gear Ratio is typically high (e.g., 3.5:1), meaning the engine needs to rotate more times to turn the wheels once. This is ideal for starting and low-speed driving.
  • Top Gear Ratio is usually low (e.g., 0.7:1), meaning the engine rotates fewer times to turn the wheels once. This is suitable for high-speed cruising.

2. What is RPM (Revolutions Per Minute)?

RPM stands for Revolutions Per Minute, which measures how fast the engine is running. It directly impacts the vehicle's power output and fuel efficiency:

  • Low RPM: Ideal for economical cruising, with better fuel efficiency but lower power output.
  • High RPM: Ideal for acceleration or climbing, with higher power output but lower fuel efficiency.

3. Relationship Between Gear Ratio and RPM

The transmission gear ratio is related to RPM through the following formula:

RPM = (Vehicle Speed × Gear Ratio × Final Drive Ratio × 336) / Tire Diameter (in inches)

Where:

  • Vehicle Speed: Speed of the vehicle (in mph).
  • Gear Ratio: Gear ratio of the current gear.
  • Final Drive Ratio: Rear axle ratio.
  • Tire Diameter: Diameter of the tire (in inches).

4. How to Calculate RPM?

Here’s an example calculation:

Vehicle Speed: 60 mph

Gear Ratio: 1.5 (4th gear)

Final Drive Ratio: 3.73

Tire Diameter: 28 inches

Calculation:

RPM = (60 × 1.5 × 3.73 × 336) / 28 = 2,520 RPM

5. Impact of Gear Ratio on Vehicle Performance

  • High Gear Ratio (e.g., 3.5:1):
    • Pros: Provides more torque, ideal for starting, climbing, and towing.
    • Cons: Higher RPM at high speeds, lower fuel efficiency.
  • Low Gear Ratio (e.g., 0.7:1):
    • Pros: Lower RPM at high speeds, better fuel efficiency.
    • Cons: Weaker power during acceleration and starting.

6. Types of Transmissions

  • Manual Transmission: The driver manually selects gears with fixed gear ratios.
  • Automatic Transmission: The transmission automatically selects the optimal gear ratio.
  • Continuously Variable Transmission (CVT): No fixed gear ratios; it adjusts continuously to maintain optimal RPM.

7. Practical Applications

  • Performance Cars: Use higher gear ratios for better acceleration.
  • Economy Cars: Use lower gear ratios for better fuel efficiency.
  • Off-Road Vehicles: Use very high gear ratios to provide more torque for challenging terrains.
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