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Axle Ratio/Tire Size Calulator

Here are a few calculators that may be useful in deciding tire size, gear ratios, and other stuff. These should be compatible with Netscape 3.x and MS Internet Explorer 3.x or above.

Ever wonder how far off your speedometer is with your new bigger tires? I'm using a simple ratio calculation, so this info will only approximate your corrected speed and depends on the accuracy of tire size diameters (assumimg nothing but tire size has changed).

  Speedo converter 
Original Tire Diameter:  
New Tire Diameter:  		 Speedometer Reading (MPH):  Corrected Speed (MPH): 
Okay, so you've torn your pumpkin apart and have the ring gear and pinion gear teeth count. This calculator will give you the gear ratio, just plug in the numbers.
  Ring Gear/Pinion Gear Teeth to Gear Ratio
Ring Gear Teeth Count: / Pinion Gear Teeth Count: Gear Ratio:

Now that you have your truck lifted, you want bigger meats. They look cool and have the potential of being very functional, but they may also be robbing you of power/gas mileage. This calculator will get you back to a ratio that's closer to your original. Enter the values on the left and press Compute. 

  Find new Gear Ratio with new tire size 
New Tire Diameter:  
Old Tire Diameter:  		 Current Gear Ratio:  New Gear Ratio: 
 

Ever wonder what your low-low-low gear ratio is, your "crawl ratio"? You'll need to do a little research by finding out the transfer case and transmission ratios first. Enter your values on the left side, press Compute and your answer will be on the right. 

  Find Overall Crawl Ratio 
Transmis Ratio: TransCase Ratio: Axle Ratio:  Overall Ratio: 

I've spend a bunch of time trying to WAG (wild ass guess) my actual MPH when going down the road. By knowing your gear ratios and tire size you'll get a more accurate idea here. Enter the value on the left, press Compute. 

  Find MPH 
RPM:  Tire Diameter:  
Axle Ratio: Transmis Ratio: TransCas Ratio: 		 MPH: 

I suppose if you don't have a tachometer you could use this form, otherwise it's only useful to find out how accurate your Tach is. Enter the values on the left, press Compute. 

  Find RPM 
MPH: Axle Ratio: Transmis Ratio: TransCas Ratio:  
Tire Diameter:  		 RPM: 

This formula is a nice way to get the tire diameter of those metric tires that are common on just about everything stock. For example a 265/75R16 would be around 31.6 inches tall. Enter the numbers into this form in the order you read them from the tire and press Compute. 

  Convert P-Metric tire to Tire Diameter inches 
Example: 195/75R15 
/  R 		 Tire Diameter: 

These calculators created by Mark Medina - www.4Lo.com

Gear Ratio / Tire Size Table

Good "rule of thumb" calculation is to mutiply .12 by your tire diameter. (.12 X 38" = 4.56)
(see more formulas at bottom of page)

The below table can be used to get a rough idea on gear ratios. The colors represent ideal RPM's at highway speeds (65). For highway cruising and best fuel economy stay towards the yellow (2600 rpm), around town daily driving is color coded green (2800 rpm), and for better towing power or just more 4-low power use the ratios near the red (3100 rpm). These calculations are assuming a manual transmission with a 1:1 ratio. If you drive an automatic your RPMs will be higher, and the opposite is true if you have overdrive (your RPMs will be lower).

Better Gas Mileage  Close to Factory Ratio  More Power

Gear Ratio
T
i
r
e


D
i
a
m
e
t
e
r
3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17
27" 2677 2766 2872 3017 3163 3325 3454 3689 3947 4150 4279 4352 4619 4991 5800
28" 2582 2668 2769 2909 3050 3206 3331 3557 3806 4001 4126 4196 4454 4813 5593
29" 2493 2576 2674 2809 2945 3095 3216 3434 3675 3863 3984 4052 4300 4647 5400
30" 2410 2490 2584 2715 2846 2992 3109 3320 3553 3735 3851 3917 4157 4492 5220
31" 2332 2409 2501 2628 2755 2896 3008 3213 3838 3614 3727 3790 4023 4347 5051
32" 2259 2334 2423 2546 2696 2805 2914 3112 3331 3501 3610 3672 3897 4211 4894
33" 2191 2263 2349 2469 2588 2720 2826 3018 3230 3395 3501 3561 3779 4093 4745
34" 2126 2197 2280 2396 2512 2640 2743 2929 3135 3295 3398 3456 3668 3963 4606
35" 2065 2134 2215 2328 2440 2565 2664 2845 3045 3201 3301 3357 3563 3850 4474
36" 2008 2075 2154 2263 2372 2493 2590 2766 2961 3112 3209 3264 3464 3743 4350
37" 1954 2019 2095 2203 2308 2426 2520 2692 2881 3028 3123 3176 3370 3642 4243
38" 1902 1966 2040 2144 2247 2362 2454 2621 2805 2948 3040 3092 3282 3546 4121
39" 1854 1915 1988 2089 2190 2302 2391 2554 2733 2873 2962 3013 3198 3455 4015
40" 1807 1867 1938 2037 2135 2244 2331 2490 2664 2801 2888 2937 3118 3369 3915
41" 1763 1822 1891 1987 2083 2189 2275 2429 2599 2733 2818 2866 3042 3287 3819
42" 1721 1778 1846 1940 2033 2137 2220 2371 2538 2668 2751 2798 2969 3208 3728
43" 1681 1737 1803 1894 1986 2087 2169 2316 2479 2606 2687 2733 2900 3134 3642
44" 1643 1698 1762 1851 1941 2040 2119 2263 2422 2546 2626 2670 2834 3063 3559

Popular Transmission Ratios
Manual
Transmissions:
AMC SR4 (Borg-Warner)
Jeep
1st 2nd 3rd 4th
4.07 2.39 1.49 1.00
SM 420
1st 2nd 3rd 4th
7.00 3.60 1.70 1.00
SM 465 (MUNCIE)
GM, Chevy
1st 2nd 3rd 4th
6.55 3.58 1.57 1.00
T-176
Jeep
1st 2nd 3rd 4th
3.52 2.27 1.46 1.00
T-177
Jeep
1st 2nd 3rd 4th
3.82 2.29 1.46 1.00
T-178
Jeep
1st 2nd 3rd 4th
3.00 2.08 1.46 1.00
Mazda 5-spd
Ford, Mazda?
1st 2nd 3rd 4th 5th
3.40 2.20 1.50 1.00 0.79
NV3500
Chevy
1st 2nd 3rd 4th 5th
4.02 2.32 1.40 1.00 0.73
NV4500
Chevy
1st 2nd 3rd 4th 5th
5.61 3.04 1.67 1.00 0.73
ZF S6-650
Chevy
1st 2nd 3rd 4th 5th 6th
5.79 3.31 2.10 1.31 1.00 0.76
Automatic
Transmissions:
TH 350
Chevy
1st 2nd 3rd
2.52 1.52 1.00
TH 400
GM, Chevy, Jeep
1st 2nd 3rd
2.48 1.48 1.00
TH 700R4 / 4L60E
GM, Chevy
1st 2nd 3rd 4th
3.06 1.62 1.00 0.70
4L80-E
Chevy
1st 2nd 3rd 4th
3.10 1.48 1.00 0.75
Allison 1000 Series
Chevy
1st 2nd 3rd 4th 5th
3.10 1.81 1.41 1.00 0.71
C-4/C-5/C-6
Ford
1st 2nd 3rd
2.46 1.46 1.00
Ford AOD
Ford
1st 2nd 3rd 4th
2.40 1.47 1.00 0.67
TORQUEFLITE 727
Jeep, Dodge
1st 2nd 3rd
2.45 1.45 1.00
       Popular Transfer Case Ratios
 
 
Dana 300
Jeep
Lo Hi
2.62 1.00
Borg Warner 1356
Ford
Lo Hi
2.69 1.00
DANA/Spicer 18
Jeep
Lo Hi
2.46 1.00
DANA/Spicer 20
Jeep, IH (TC-145), GM, Ford
Lo Hi
2.00 1.00
NP 203
Chevy, Ford, Dodge
Lo Hi
2.00 1.00
NP 205
Chevy, Ford, Dodge, IH
Lo Hi
1.98 1.00
NP 207/208
Jeep, Chevy, Ford, Dodge
Lo Hi
2.61 1.00
NP 231
Jeep (YJ)
Lo Hi
2.72 1.00
Toyota (67-74)
Land Cruiser
Lo Hi
2.31 1.00
Copyright © 1997-2005 by Mark I. Medina - www.4Lo.com

Vehicle / Tire Size Table

KEY
A = STOCK VEHICLE
B = MINOR FENDER TRIMMING
C = MAJOR FENDER TRIMMING/FLARES
D = SUSPENSION LIFT (IN.)
E = BODY LIFT (3-IN.)
* = PROPER WHEEL OFFSET CRUCIAL

VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
CHEVY/GMC
’82-’93 S/T-trucks A D (2) D (3,4) B,D (4) D (7)
’94–’03 S/T trucks A D (2,3)* B,D (3*) D (6*)
’73–’87 pickups A B D (2.5) B B,D (4) B,D (6) B,D (6) D (8) B,D (8) D (12) D (10),E
’88–’98 pickups A B D (4) B,D (6) C,D (6) D (6), E
’73–’91 K-5 Blazer/Jimmy A B D (2.5) B B,D (4) B,D (6) B,D (6) D (8) B,D (8) D (12) D (10),E
’92–’95 Blazer/Yukon/Tahoe (fullsize) A B D(4) B,D (6) C,D (6) D (6), E
’95–’99 Tahoe/Yukon A B B,D(2.5) D (4) D (6) E,D (6)
’00–’03 Tahoe/Yukon A A B D (2.5*) B,D (3*) D (6*) C,D (6)
’98–’03 Yukon/Denali A B D (4)
’73–’91 Suburban A B D (2.5) B B,D (4) B,D (6) B,D (6) D (8) B,D (8) D (12) D (10),E
’92–’00 Suburban A B D (4) B,D (6) C,D (6) D (6), E
’01–’03 Suburban/Avalanche HD A B D (2.5) D (6) C,D (6) D (8)
’99–’03 Silverado 1500/2500/3500 HD A A B D (2.5*) B,D (3*) D (6*) C,D (6)
’02–’03 Avalanche 1500 A B D (4,6)
’02 H2 Hummer A D (6*) D (6*) C,D (6*) D (10*)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
DODGE
’86–later D50 A B,E
Pre-’93 Dakota A E C,D (3)
’93–later Dakota A B D (3)
Pre-’93 W150/Ramcharger A B, D D (3.5) B,D (2) B,D (4) B,D (5) B,D (4), E B,D
Pre-’93 W250/W350 A B, D D (3.5) B,D (2) B,D (4) B,D (5) B,D (4), E D (6) B,D (5), E
’94–’03 Ram 1500 A D (2,3*) B,D (4*) D (6*) D (8*)
’94–’03 Ram 2500/3500 A A A A D (3*) D (5*) E,D (5*) E,D (8,9*)
’98–later Durango/Dakota A B E (3)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
FORD
’66–’77 Bronco A C C,D (3) B,C,D (3) C,D (4) D (6) C,D (6) E,D (6) E,D (8)
’78–’79 Bronco A D (2) B D (3) B, D D (5),E C,D (5) D (9) B,E,D (8)
’69–’79 F-150 A D (2.5) D (3.5) D (4) D (4) B,D (4) B,D (6) B,E,D (8)
’80–’96 F-150, Bronco A D (3) B,D (3) E,D (3) D (6) E,D (6) D (8) B,D (8) E,D (8) B,E,D (8)
’97–later F-150/F-250(LD 7-lug) A B D (4*) B,D (4*) B,D (6*) E,D (6*) B,D (6*),E B,D (6*),E D (10,12)*,E
’73–’77 F-250 A D (2) D (2), E B,D B,D B,D
’771⁄2–’79 F-250 A D (2) B,D (2) D (4) D (6) B,D (6) C,D (4) B,D
’80–’97 F-250/’80–’85 350 A A B B,D (2) D (4) D (6) B,D (2) D (4), E E,D (6)
’861⁄2–’91 F-350 A D (2) B, D (2) D (4) B,D (4) D (6) B,D B,D
’92–later F-350 A B,D (1,2) D (4) B,D (4) D (6)
’99–’03 Super Duty A A A D (2*) D (4*) D (6*) D (8*) B,D (11*)
’83–’92 Ranger/Bronco II A B D (4) B,D (4) B,D (4), B,D (6) C,D
’93–’97 Ranger A B D (2*) D (4*) E,D (4*)
’98–’03 Ranger IFS A B D (1.5,2*) D (4*) E,D (4*)
’01–03 SportTrac A D (4) D (4) E,D (4)
’97–’01 Expedition/Lincoln Navigator A D (4)
’02–’03 Expedition/Lincoln Navigator A D (3) D (4) D(5)
Pre-’95 Explorer B D (2.5) D (4) C,D (4)
’96–01 Explorer A B D (2) D (4)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
INTERNATIONAL
Scout II A D (2.5) B,D D (2.5) C,D
ISUZU
Pickup A B B,E C,E
Amigo, Rodeo, Trooper II A B,D (2) C,D (2)
Trooper A D (3)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
JEEP
MB, CJ-2A/3A/3B A D (1) D (2.5)
’76-’86 CJ-5/6/7/8 A D (2.5*) D (3*) D (3*),E D (4*), E B,D (6*) B,D (6*), E
’87–’96 Wrangler YJ D (2.5) D (3) B,D (4) B,D (6) B,D
’97–later Wrangler TJ A* D (2) D (3,4) B, D (6,7) D (11)
’84–up Cherokee A D (3) C, D (3)
Cherokee Chief/Comanche pickup A D (3) D (4), E
Wagoneer A B B, D (4) C, D (4) C,D (4) E
’93-’98 Grand Cherokee A C, D (3) C, D (4)
’99-’03 Grand Cherokee A D (2)
’02 Liberty A D (2*) D (3.5*)
KIA
Sportage A B,D (2.5)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
LAND ROVER/RANGE ROVER
’88–later Range Rover D (2)
Defender 90 A B D (2.5)
Discovery/Discovery II A D (2.5)
MAZDA
Pre-’87 pickup B E B,E C,E
’88—later pickup A B E C,E
’93–’97 pickup A B D (2*) D (4*) E,D (4*)
’98–’03 pickup IFS A B D (1.5, 2*) D (4*) E,D (4*)
MITSUBISHI
’82–’86 pickup A B B,E C,E
’87–later pickup A E B,E
Pre-’92 Montero A E B,E
’92–’03 Montero/Montero Sport A E B,E
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
NISSAN
Pre-’861⁄2 pickup A B E B,E D
’861⁄2–later pickup A B B,D (4)
Pre-’96 Pathfinder A B B,D (4)
’96–later Pathfinder A
’00–later Xterra A D (2,3*) E,D (3*)
SUZUKI
Samurai A D (1.5) D (3) B,D (3) D (3), E B, D (3)
Sidekick A B C B,D (2)
VEHICLE MAKE/MODEL 27x9.50 28x9.50 29x9.50 30x9.50 31x10.50 32x11.50 33x12.50 34 35x12.50 36x15 37x12.50 38.5x15 39 40x17 42 44x18
TOYOTA
’79–’85 pickup A B,D E,D (4) B, D (7) D, (7), E B,C C,D
’86–’96 pickup A B, D (2) D (3) B,D (4) E,D (4) B,D C,D
’96–’03 Tacoma A D(2.5) B, D (2.5) D (3,4*) D (6) E,D (6)
’93-’96 T100 A D (1.5) D (3)
’99–’03 Tundra A A D (2*) E,D (2)
Land Cruiser FJ40 A C C,D
Land Cruiser Wagon FJ60 A B B,D
Land Cruiser Wagon FJ80/Lexus LX450 A D (2.5)
’84-’89 4Runner A D (3) B,D (4) C,D (4) E,D (4)
’90–’96 4Runner A B, D (2) D (2.5)
’97–’02 4Runner A B, D (2)
’02 GX 470 A

Lug Nut / Bolt Pattern

YEAR MODEL BOLT PATTERN LUG NUT SIZE
JEEP
84-02 XJ 5on4.5 1/2
97-04 TJ 5on4.5 1/2
87-96 YJ 5on4.5 1/2
02-04 LIBERTY 5on4.5 1/2
92-98 ZJ GRAND CHEROKEE 5on4.5 1/2
99-04 WJ GRAND CHEROKEE 5on5 1/2
46-86 ALL CJ'S 5on5.5 1/2
74-83 J-10 SERIES 6on5.5 7/16
ALL J-20 SERIES 8on6.5 9/16
74-83 F/S CHEROKEE 6on5.5 7/16
DODGE
87-90 DAKOTA 2-4WD 5on4.5 1/2
91-04 DAKOTA 2-4WD 6on4.5 1/2
98-03 DURANGO 2-4WD 6on4.5 1/2
74-84 RAM 1500 2WD 5on4.5 1/2
85-01 RAM 1500 2WD 5on5.5 1/2
74-80 RAM 4WD W/O HUBS 5on4.5 1/2
80-93 RAM 4WD W/HUBS 5on5.5 1/2
94-01 RAM 1500 4WD 5on5.5 1/2
02-04 RAM 1500 (NEW BODY) 2/4WD 5on5.5 9/16
46-81 3/4-1 TON 2WD 8on6.5 1/2
82-93 3/4-1 TON 4WD 8on6.5 1/2
94-04 RAM 2500-3500 2/4WD 8on6.5 9/16
FORD
03-04 EXPEDITION 2-4WD 6on135 14X2.00
03-04 NAVIGATOR 2-4WD 6on135 14X2.00
00-02 EXPEDITION 2-4WD 5on135 14X2.00
00-02 NAVI / BLKWD 2-4WD 5on135 14X2.00
97-99 EXPEDITION 2-4WD 5on135 12X1.75
97-99 NAVIGATOR 2-4WD 5on135 12X1.75
83-97 RANGER / BRONCO II 4WD 5on4.5 1/2
98-04 RANGER 4WD 5on4.5 1/2
01-04 SPORT TRAC 2/4WD 5on4.5 1/2
83-04 RANGER / BRONCO II / EXPLORER 2WD 5on4.5 1/2
90-94 EXPLORER 4WD 5on4.5 1/2
95-04 EXPLORER 4WD 5on4.5 1/2
49-96 ALL 1/2 PICKUP 4WD 5on5.5 1/2
49-96 ALL 1/2 PICKUP 2WD 5on5.5 1/2
66-96 FULL SIZE BRONCO 5on5.5 1/2
97-99 F-150 PICKUP 2-4WD 5on135 12X1.75
00-04 F-150 PICKUP (HERITAGE) 2-4WD 5on135 14X2.00
2004 F-150 PICKUP (NEW BODY) 2-4WD 6on135 14X2.00
97-99 F-250 LT DUTY 2-4WD 7on150 12X1.75
55-79 F-250 / F-350 4WD 8on6.5 9/16 OR 1/2
55-79 F-250 / F-350 2WD 8on6.5 9/16 OR 1/2
80-98 F-250 / F-350 (OLD BODY) 4WD 8on6.5 9/16
80-98 F-250 / F-350 (OLD BODY) 2WD 8on6.5 9/16
03-04 F-250 / F-350 / EXCURSION 4WD 8on170 14X1.50
03-04 F-250 / F-350 / EXCURSION 2WD 8on170 14X1.50
99-02 F-250 / F-350 / EXCURSION 4WD 8on170 14X2.00
99-02 F-250 / F-350 / EXCURSION 2WD 8on170 14X2.00
YEAR MODEL BOLT PATTERN LUG NUT SIZE
TOYOTA
72-95 PICKUP 2WD 5on4.5 12x1.50
79-95 PICKUP 4WD 6on5.5 12x1.50
96-04 RAV-4 2-4WD 5on4.5 12x1.50
93-99 T-100 2WD 6on5.5 12x1.50
93-99 T-100 4WD 6on5.5 12x1.50
95 1/2-04 TACOMA 2WD 5on4.5 12x1.50
95 1/2-04 TACOMA PRERUNNER 2WD 6on5.5 12x1.50
95 1/2-04 TACOMA 4WD 6on5.5 12x1.50
00-04 TUNDRA 2-4WD 6on5.5 12x1.50
64-97 LANDCRUISER / LX450 6on5.5 12x1.50
98-04 LANDCRUISER / LX470 5on150 14x1.50
84-95 4 RUNNER 2-4WD 6on5.5 12x1.50
96-04 4 RUNNER 2-4WD 6on5.5 12x1.50
CHEVY/GMC
82-03 S-10 / S-15 PICKUP 2WD 5on4.75 12X1.50
BLAZER / JIMMY 2WD
82-03 S-10 / S-15 PICKUP 4WD 5on4.75 12X1.50
BLAZER / JIMMY 4WD
02-04 ENVOY / TRAILBLAZER 2/4WD 6on"5" 12X1.50
65-87 C-10 PICKUP 2WD 5on5 1/2
88-98 C-1500 PICKUP 2WD 5on5 14X1.50
99-04 C-1500 PICKUP 2WD 6on5.5 14X1.50
92-99 SUBURBAN / TAHOE 2WD 5on5 14X1.50
YUKON / DENALI 2WD
BLAZER / ESCALADE 2WD
00-04 SUBURBAN / AVALANCHE 2WD 6on5.5 14X1.50
YUKON & XL / DENALI 2WD
BLAZER / TAHOE / ESCALADE 2WD
69-87 PICKUP 4WD 6on5.5 7/16
88-04 K-1500 PICKUP 4WD 6on5.5 14X1.50
69-91 BLAZER / SUBURBAN 4WD 6on5.5 7/16
92-04 SUBURBAN / AVALANCHE 4WD 6on5.5 14X1.50
YUKON & XL / DENALI 4WD
BLAZER / TAHOE / ESCALADE 4WD
65-87 3/4 & 1 TON C20 C30 2WD 8on6.5 9/16
PICKUP / SUBURBAN 2WD
65-87 3/4 & 1TON K20 K30 4WD 8on6.5 9/16
PICKUP / SUBURBAN 4WD
88-04 C2500-K2500 3/4 TON & HD 2/4WD 8on6.5 14X1.50
88-04 C3500-K3500 1 TON & HD 2/4WD 8on6.5 14X1.50
01-04 C1500HD - K1500HD 2/4WD 8on6.5 14X1.50
AVALANCHE 2500 2/4WD
SUBURBAN 2500 2/4WD
03-04 H2 8on6.5 14X1.50
SUZUKI
86-94 SAMURAI 2-4 WD 5on5.5 12X1.25
89-98 SIDEKICK 2-4 WD 5on5.5 12X1.25
I.H.C.
ALL 1/2 TON SCOUT I / II 5on5.5 1/2
69-84 3/4 TON SCOUT 8on6.5 1/2
NISSAN
72-03 PRERUNNER FRONTIER , P/U , 6on5.5 12X1.25
PATHFINDER , HARDBODY 2WD
72-03 FRONTIER , PATHFINDER 6on5.5 12X1.25
PICKUP, HARDBODY 4WD
00-04 XTERRA 6on5.5 12X1.25