Gear Ratios

TerryMason

TerryMason

Administrator
Staff member
Gear Ratio Calculator

Gear Ratio Calculator


This simple Gear Ratio calculator assumes that you're running around 65 MPH


All you need to do is look at your tire size on the left, then find out how many RPMs your engine is at when you are doing 65 MPH, and that will give you your Gear Ratio. the blue blocks are good gas mileage, green it a good medium and red is for more power.





Gear Ratio
This chart will tell you the rpm needed to reach 65 mph




Tire
Size












3.313.423.553.733.914.114.274.564.885.135.295.385.71


27



2677276628723017316333253454368939474150427943524619


28



2582266827692909305032063331355738064001412641964454


29



2493257626742809294530953216343436753863398440524300


30



2410249025842715284629923109332035533735385139174157


31



2332240925012628275528963008321338383614372737904023


32



2259233424232546269628052914311233313501361036723897


33



2191226323492469258827202826301832303395350135613779


34



2126219722802396251226402743292931353295339834563668


35



2065213422152328244025652664284530453201330133573563


36



2008207521542263237224932590276629613112320932643464


37



1954201920952203230824262520269228813028312331763370


38



1902196620402144224723622454262128052948304030923282


39



1854191519882089219023022391255427332873296230133198


40



1807186719382037213522442331249026642801288829373118


41



1763182218911987208321892275242925992733281828663042


42



1721177818461940203321372220237125382668275127982969


43



1681173718031894198620872169231624792606268727332900


44



1643169817621851194120402119226324222546262626702834

<tbody>
</tbody>




Blue = 2600 RPM​

Better Mileage​



Green = 2800 RPM
Around factory​


Red = 3100
RPM
Good Power



<tbody>
</tbody>
 
Last edited:

Re: Jeep Gear Ratio Calculator

Terry,

Should I assume I am driving in 5th gear to reach 65mph, please confirm the gear.:rolleyes:
 
Last edited by a moderator:
i have a four cyl jeep and i put a 4 inch lift and 35 inch tires my jeep cant go fast enough to put her in 5th gear i drive aeround in 3rd and 4th gear and she can only do 100 km/h.. i want my jeep to go faster and have more power for in the mud and in sand.. can u plz tell me what to do with my jeep
 
captjanes said:
i have a four cyl jeep and i put a 4 inch lift and 35 inch tires my jeep cant go fast enough to put her in 5th gear i drive aeround in 3rd and 4th gear and she can only do 100 km/h.. i want my jeep to go faster and have more power for in the mud and in sand.. can u plz tell me what to do with my jeep
Click to expand...
Regear the axles to 4.88, that is as low as you can go with the stock axles, even though lower is better.
 

Re: Jeep Gear Ratio Calculator

kawstxf15 said:
Terry,

Should I assume I am driving in 5th gear to reach 65mph, please confirm the gear.:rolleyes:
Click to expand...
I think it would be 4th, or 1:1 transmission ratio.

Regardless of transmission gear, find your stock gear ratio on top and move down until your at your stock tire size. Record that RPM. Then move to your current or desired tire size and move across the chart to the right until you find an RPM similar to the previous number. Move up and find the suggested gear ratio for the new tire size.
 
so what ur saying is that to get more speed and power out of my jeep i has to change the gears in the front and rear differentials axels? someone told me that i had to change a gear in the transmission is this true or do i just have to regear the axels? and can u tell me how about going to regear the axles.. where can i order gears to? thanks in advanced
 
Hello to terry mason.. I have been looking into 4:88 gears and have found that your chart is wrong 31" tires and 4:88 gears you have 3838 and it should be 3438 thanks team twisted off road.
 

Team Twisted Off Road said:
Hello to terry mason.. I have been looking into 4:88 gears and have found that your chart is wrong 31" tires and 4:88 gears you have 3838 and it should be 3438 thanks team twisted off road.
Click to expand...
It's all relative to what gear the transmission is in, and isn't really necessary information to use the chart.

To simply use the chart, find the given RPM for stock tire size and stock gear ratio. Then go the line of the tire you want to run, and move over until you find a similar RPM, or slightly higher, that is your recommended gear ratio.
 
bounty__hunter said:
it's all relative to what gear the transmission is in, and isn't really necessary information to use the chart.

To simply use the chart, find the given rpm for stock tire size and stock gear ratio. Then go the line of the tire you want to run, and move over until you find a similar rpm, or slightly higher, that is your recommended gear ratio.
Click to expand...


gear_ratios.jpg
 

Re: Jeep Gear Ratio Calculator

I am new. In what gear? I have 5 speed manual, 4 cylinder with 35" tires. I think the previous owner put the big tires on to look cool without thinking about the effects it would have on performance. Any of your suggestions will be highly regarded. Thanks in advance for the help.
 
Welcome to the Z. 4.88 is as low as you can go with the stock axles, so that's your best choice.

I run a 2.5L 5spd and 35" tires, 5.38 gears work perfect for me but I had to upgrade to Dana 44 axles.
 
You must log in or register to reply here.

Similar threads

P
Gear Ratios
Replies
4
Views
3K
Bounty__Hunter
Bounty__Hunter
Back
Top