I'm getting ready to regear my 13 JK from 3.21's. Last summer I towed my bike and my brother in laws out to Delaware and New Jersey. Plus the wives, kids and all our stuff (above the limit). It pulled fine.... in 4th gear, occasionally getting into 5th. My goal is to gear it so it effectively turns 5th gear into my current 4th gear- (if 6th is OD). Should be easy math if I could figure out the ratios of the tranny? Thinking it will fall between the 4.88's or 5.13's and just want another way to justify the next expenditure.

So, does anybody know what the ratios of each of the gears IS in our manual trannys?

 

The gear ratio's are based on your ring and pinion in the diff's. Not your transmission.


It all depends on what tire size you're running.

 

There are charts for what your looking for.

Most people seem to like 4.56's in 2012 and up. Good for running stock to 35's.

 

Yes and No. Using arbitrary ratios to explain 1st gear is 4.00 to 1, 2nd is 3 to 1, 3rd is 2 to 1 and Then 4th is 1 to 1. IN 4th gear, I agree with you, the axel ratio is the only one that matters. But in third it would be the axel ratio X the transmission ratio that give you the final drive ratio. This is why I want to know the tranny ratios-at least for 4th and 5th gear.

 

I think this is what you are asking for:

2012 Transmission Ratios (I believe 2013 is the same.)

Manual
1st 4.46
2nd 2.61
3rd 1.72
4th 1.25
5th 1.00
6th 0.797

 

Thats kind of what I expect (4.56 t 4.88 maybe up to 5.13) Although all the charts I see just cover the Axel ratios used versus RPM at 70mph.

To try to clarify my question- I want to change my final drive ratio in 5th gear to the final drive ratio of 4th gear. To do that I need to know what the ratio of each transmision gear selection is, do some math and it should help narrow down between 4.56 and 5.13.

same general idea as calculating crawl ratio but in high range...hope that makes better sense.

 

[QUOTE=ronjenx;3869124]I think this is what you are asking for

SWEET. Exactly! thank you!

 

So, (1.25 x 3.21= 4.0125) 4.10 would do it, Or 4.56 with 35's. 5.13 is WAY to low for what I do.


Thanks Again!

 

5.13 is great on 37's

But even then, if it was a DD you might want something in the 4's!

Matthew