Gears and RPM

MOX4x4

MOX4x4

New member
Anyone interested in creating a Gear/RPM/Tire Size database? It could be helpful for the "What gear should I run" question.

2017 JK 2-Door
3.6L
35" Nitto RidgeGrapplers
4.56 Gears
2,300 rpm at 60 MPH.

JK60mph.jpg
 
Have you seen the charts that already exist?

3.6L

10958f88f8c24be10e0c763a04951f80.png


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3.8L

jk_ratio-chart-12.png
 
aermotor said:
Have you seen the charts that already exist?

3.6L

10958f88f8c24be10e0c763a04951f80.png


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3.8L

jk_ratio-chart-12.png
Click to expand...

I'm actually curious if this would provide some clarification on whether or not those tire sizes are sidewall heights or true ride heights.
My 37's and 5:13's is almost dead on to the "35" on that chart, not 37s.
 
JKDream said:
I'm actually curious if this would provide some clarification on whether or not those tire sizes are sidewall heights or true ride heights.
My 37's and 5:13's is almost dead on to the "35" on that chart, not 37s.
Click to expand...

Pretty sure they are just stated heights and not real world heights.
 
Ok, never mind. Just went out and checked, 70mph with my short 35's. Looks like the chart is spot on 2,700.
 
JKDream said:
Interesting. I'm auto - close to 3k rpms at 70.
Click to expand...


knotabyte said:
might need to get the GPS out and check the MPH.
Click to expand...

Yep, verify with GPS, I'm almost willing to bet you flashed the wrong tire size. It's easy to do. You need to measure from the ground to the center of the axle and multiply by 2. But GPS will get you there too. Just keep adjusting tire size until you get it right. :thumb:
 
JKDream said:
I'm actually curious if this would provide some clarification on whether or not those tire sizes are sidewall heights or true ride heights.
My 37's and 5:13's is almost dead on to the "35" on that chart, not 37s.
Click to expand...

It's real world height. My 315 duratracs are actually 33.75" tall with weight on them.
 
does the real world hight matter? I mean, if you have like 33,5 inch tall with x amount of cargo and empty you have 34 inch of hight, you still have the same radius of the tire so I do not understand all this fuzz about real hight an mesured hight.

For me the interesting size must be when the tired is unloaded becuase you should always have the same tire diamater, radius with or withoult load.

Or I´m totaly out on a bicycle tour here?
 
Bingobelle said:
does the real world hight matter? I mean, if you have like 33,5 inch tall with x amount of cargo and empty you have 34 inch of hight, you still have the same radius of the tire so I do not understand all this fuzz about real hight an mesured hight.

For me the interesting size must be when the tired is unloaded becuase you should always have the same tire diamater, radius with or withoult load.

Or I´m totaly out on a bicycle tour here?
Click to expand...

The distance between the center hub of the wheel and the ground will change as you add weight to the vehicle. This will also change depending on the air pressure.
 
sjd78 said:
37" Trail Graps here with auto, 5:13's and right around 2800rpm at 70mph.
Click to expand...

How do you like that if you had to do it again would you go 4.88 or stay 5.13's

Whats everyone else's opinion I have a 2013 JKU with 3.6 and an Auto on 37's I was planing on re-Gearing as well but I'm at a crossroads between 4.88's and 5.13's.
Its My Daily Driver and I like to drive it to the trail.
 
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