Rubicon on 37s is geared the same as a sport on 33s

[Oscar Indy]

Link to calculator: http://www.grimmjeeper.com/gears.html

This is a fun calculator that blows that chart that's floating around about gears out of the water.

In 2 high and 4 high the difference between a sport with 3.73 gears and a Rubicon on 4.10 gears is massive. Once you move the Rubicon to 37 in tires the drive ratios balance out between the two to where the 2 and 4 high Difference has the the Sport doing only 35 more RPMs to maintain 70mph. This is shown in the final two charts of the above image.

Now looking at 4lo the Rubicon gearing in the transfer case outshines the sport dramatically even with a 4 in taller tire. You can compare this in the final drive section of the chart and the crawl speed section.

Conclusion. The Rubicon on 37s should run very similar to the Sport/Overland with 33s. The sport max tow will have the same onroad as the Rubicon but it's off-road crawl ratio will be lower when equiped with 37s.

One factor that the chart doesn't account for is additional rotational mass of larger tires. Turning the extra weight puts some load on the engine but generally this is noticed in lower gas mileage not necessarily power output.

So if you are wishy washy on tire size this may or may not help you out.

Sponsored

 

[DirtyD]

Can you post a link to where you found that calculator?

 

[Oscar Indy]

Can you post a link to where you found that calculator?

Sure
http://www.grimmjeeper.com/gears.html
Been using it for years.

 

[DirtyD]

Awesome, thanks! First Jeep so there a lot of little things I am discovering as far as reference sites go....

 

[ACAD_Cowboy]

I've been using http://www.nightrider.com/biketech/calc_speed_rpm.htm for ever, lets you input all your gear and tire data and then analyze based on speed or RPM.

 

[DankjeeP]

You can do it yourself. Just multiply trans gear * tcase * axle. etc.
But it is nice to have it all in one place like a spreadsheet.

Sponsored