Crawl ratio on Rubis?
Thread Starter
JK Junkie
Joined: Mar 2009
Posts: 2,368
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From: Scottsdale, AZ
Crawl ratio on Rubis?
I heard on Rubis they have this crawl ratio of something 4:1 and an X has a 3:1 or something like that. When they say the ratio are they talking about the gearing of the axles? One day I want to be able to crawl over rocks but I have an X. What determines the crawl ratio? I heard it allows the Rubis to crawl better but what would I have to change in order to get a ratio like the rubis or better?
JK Newbie
Joined: Oct 2010
Posts: 5
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From: Mesa, Arizona
The crawl ratio is determined by the your 1st gear ratio x your gear ratio in your axel x the ratio in your transfer case.
The transfer case in a rubicon is 4 to 1 for 4Low, in an X it is 2.73 to 1.
Hopefully this helps
The transfer case in a rubicon is 4 to 1 for 4Low, in an X it is 2.73 to 1.
Hopefully this helps
JK Super Freak
Joined: Aug 2007
Posts: 1,451
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From: Winnipeg, Canada
I heard on Rubis they have this crawl ratio of something 4:1 and an X has a 3:1 or something like that. When they say the ratio are they talking about the gearing of the axles? One day I want to be able to crawl over rocks but I have an X. What determines the crawl ratio? I heard it allows the Rubis to crawl better but what would I have to change in order to get a ratio like the rubis or better?
However the total driveline must be considered, i.e. transmission, transfer case and differential (axle) gears. To get a "total" ratio.
With a six speed and a manual, I'd only worry about your diff gears if/when you get on bigger tires. If you want to crawl on rocks, go out and do it!!! you'll be surprised at how well your stock JK does.
Thread Starter
JK Junkie
Joined: Mar 2009
Posts: 2,368
Likes: 0
From: Scottsdale, AZ
Crawl ratio defined is:
The lowest combined gear, transmission, and transfer case ratio for a vehicle.
Two answers...one technical and one practical.
First, the technical:
Here is a crawl ratio calculator:
[url] www.4lo.com/calc/gearratio.htm [ /url]
(You only need the Diff ratio, Tranny 1st gear ratio, and Transfer case ratio for the calculator.)
The JK 6 speed manual transmission 1st gear ratio is 4.46:1
The JK automatic transmission 1st gear ratio is 2.84:1
The JK Rubicon transfer case ratio is 4:1
The JK Rubicon differential ratio is 4.10:1
The JK non-Rubi transfer case ratio is 2.72:1
So, using the calculator, a stock 6 speed Rubicon has a crawl ratio of 73:1
An automatic Rubicon has a crawl ratio of 46:1
With a non-Rubicon transfer case and 4.88 gears with a 6 speed, your crawl ratio would be 59:1, and with 5.13 gears it would be 62:1.
With a non-Rubicon transfer case and an automatic, with 4.88s your crawl ratio would be 38:1 and with 5.13s it would be 40:1.
With a 6 speed, Rubicon transfer case and 5.13 gears, the crawl ratio is 92:1.
Now, the practical answer:
With a non-Rubicon transfer case, a 6 speed, and 4.88 or 5.13 gears, the 59 and 62 to 1 crawl ratio is respectable--better than a stock Rubicon automatic. In most cases, it will be enough for you.
If you want to do really challenging crawling where your rig will almost idle through most difficult terrain, you could gear your axles to 5.13s and switch out your transfer case for a Rubicon one and have a 92 to 1 crawl ratio.
The downside of the lower crawl ratios is that it often feels too low for deep snow and mud or in sand because your top speed in 6th gear is pretty low.
First, with your 6 speed, gear your axles to 4.88s for 35" tires if you spend much time over 75 mph or 5.13s if you don't.
If you find that is not enough, you can buy a take-off Rubicon transfer case to switch with yours.
The lowest combined gear, transmission, and transfer case ratio for a vehicle.
Two answers...one technical and one practical.
First, the technical:
Here is a crawl ratio calculator:
[url] www.4lo.com/calc/gearratio.htm [ /url]
(You only need the Diff ratio, Tranny 1st gear ratio, and Transfer case ratio for the calculator.)
The JK 6 speed manual transmission 1st gear ratio is 4.46:1
The JK automatic transmission 1st gear ratio is 2.84:1
The JK Rubicon transfer case ratio is 4:1
The JK Rubicon differential ratio is 4.10:1
The JK non-Rubi transfer case ratio is 2.72:1
So, using the calculator, a stock 6 speed Rubicon has a crawl ratio of 73:1
An automatic Rubicon has a crawl ratio of 46:1
With a non-Rubicon transfer case and 4.88 gears with a 6 speed, your crawl ratio would be 59:1, and with 5.13 gears it would be 62:1.
With a non-Rubicon transfer case and an automatic, with 4.88s your crawl ratio would be 38:1 and with 5.13s it would be 40:1.
With a 6 speed, Rubicon transfer case and 5.13 gears, the crawl ratio is 92:1.
Now, the practical answer:
With a non-Rubicon transfer case, a 6 speed, and 4.88 or 5.13 gears, the 59 and 62 to 1 crawl ratio is respectable--better than a stock Rubicon automatic. In most cases, it will be enough for you.
If you want to do really challenging crawling where your rig will almost idle through most difficult terrain, you could gear your axles to 5.13s and switch out your transfer case for a Rubicon one and have a 92 to 1 crawl ratio.
The downside of the lower crawl ratios is that it often feels too low for deep snow and mud or in sand because your top speed in 6th gear is pretty low.
First, with your 6 speed, gear your axles to 4.88s for 35" tires if you spend much time over 75 mph or 5.13s if you don't.
If you find that is not enough, you can buy a take-off Rubicon transfer case to switch with yours.
Thank You planman
Last edited by matt852; Nov 7, 2010 at 09:05 AM.
JK Jedi Master
Joined: Feb 2008
Posts: 12,904
Likes: 185
From: Maine
Crawl ratio defined is:
The lowest combined gear, transmission, and transfer case ratio for a vehicle.
The JK automatic transmission 1st gear ratio is 2.84:1
An automatic Rubicon has a crawl ratio of 46:1
With a non-Rubicon transfer case and an automatic, with 4.88s your crawl ratio would be 38:1 and with 5.13s it would be 40:1.
The lowest combined gear, transmission, and transfer case ratio for a vehicle.
The JK automatic transmission 1st gear ratio is 2.84:1
An automatic Rubicon has a crawl ratio of 46:1
With a non-Rubicon transfer case and an automatic, with 4.88s your crawl ratio would be 38:1 and with 5.13s it would be 40:1.
Last edited by ronjenx; Nov 7, 2010 at 09:54 AM.
JK Junkie
Joined: Apr 2010
Posts: 2,123
Likes: 1
From: - - Jeep-topia - -
I almost wish I had an auto so I could snaggle up a RubiCrawler. I think I will save up for one of those 3-speed boxes for every possible gear scenario. With 5.13s and that, I would be smiling.