What is crawl ratio

[dscowell]

So I have seen on the jeep page on facebook that the new cherokee has a 56:1 crawl ratio as well as on JP magazines app they can help you calculate your crawl ratio so I was just wondering what exactly is crawl ratio?

[Chris]

Quick answer - lowest gear ratio, affected by all components of the drive train. Your truck's crawl ratio would be whatever 1st gear ratio is...

[Java]

just multiply your drivetrain. for example, my jeep has a first gear of 4:30 to 1, a low range of 2:72 to 1, and 3:73 axle gears.

4.3 x 2.72= 11.696 x 3.73= 43.6 to 1 crawl ratio

[Fordguy77]

Quick answer - lowest gear ratio, affected by all components of the drive train. Your truck's crawl ratio would be whatever 1st gear ratio is...
As Chris stated, its pretty simple.
First Gear Ratio X TCase Low Ratio X Rear Dif Ratio= Crawl Ratio

And if you have a crawl box or second tcase you just add that to the equation.

[offroadwonder]

A simple way to look at it is the number of times the engine's crankshaft will turn for every single turn of the tires. As others have stated it is the product of the transmission gear ratio X the transfer case gear ratio X the axle gear ratio.

[RidgeRunner]

And if you have a crawl box or second tcase you just add that to the equation.

Yup, my Toyota has dual transfer cases, so mine is:

1st gear 3.954 x t-case 2.27 x t-case 2.27 x axle 5.29= 107.78 to one

Then you can put 4.7:1 gears in one case and the ratio goes even lower.

[Robert B]

just cause i want to show off my tranny lol
1st 6.43X tcase 2.6 X axle 4.10 = 67.5844


i think anything over 50 is useable though i would love to get to the 100 mark personally

[Chris]

I have no idea what mine is? :eek:

[Robert B]

here chris this is one my favorite sites http://www.grimmjeeper.com/gears.html

[Chris]

Thanks Robert, mine's not too impressive but I can hit 100mph w/o worry! :rolleyes:



3.520 (1st gear) * 2.566 (low range transfer) * 3.727 (diff) = 33.66

[zukrider]

Chris, you would be able to double that in the first 1000 rpm or so due to torque converter slippage.

[Patrolman]

Yep. The automatics are a bit harder to calculate an equivalant, but I have always heard to calculate the diff x t-case and then double what the normal 1st gear ratio would be in the manual tranny to get the auto tranny at low rpm. That is one great advantage of an automatic!

[dscowell]

So is a higher crawl ratio better? and how do I figure out the first gear ratio and T-case ratio?

[Chris]

I just Googled it to get my number. :rolleyes:

[Patrolman]

A higher number equals lower speeds, which is good for crawling over obstacles. You need to know the transmission and t-case your rig has to look up the gear info. You also need to know the diff ratio. Some of that info might be on the tag in the door.

[Robert B]

dante if ur tranny is stock id just google it then use the grimm jeeper site and choose it and it gives you the numbers and what tcase do you have ????? can read the tag on the back of it

[Robert B]

and to elaborate on what jeff said the higher the final number the slower the truck moves........so a 56 crawl ratio moves faster than a 156 crawl ratio

[mattzj98]

according to the site im at 148.. not too bad!

that's a pretty sweet website

[dscowell]

Im not sure what transmission or T-Case I have exactly i believe an AX-15 and a NP 231 but Im not 100% ill check my door and see what it says once the weather clears up and calculate it and let you guys knows!

[Java]

it only really matters if you're rock crawling (boring!!) or advertising the new Cherokee. for most people even the Rubicon's 4-1 is too slow for trails and they end up running 2nd or 3rd gear. Your sleep number is probably just as important. :)

[Rick]

if you're rock crawling (boring!!):eek: Boring!!!!!!!

[Adaa60]

im bad at math cant figure mine out..

1st gear is 2.80
4low is 2.71
axles are 4.88
tires are 33's?

[Robert B]

rob you have a crawl ratio of 37.03

[Robert B]

paul that is because most people i wheel with drive too fast and beat the nuts out of their rigs lol but yes it all depends on what you wheel ...........if you never want to rock crawl then you dont need much of a ratio

[Java]

That's funny, I've been called "trailgater" because I drive fast! I should clarify that I like crawling if it's incidental to the trail, but areas that are just rock obstacles are, IMO, the most boring wheeling. It's like making the parking lot into a sport, again IMO, but to each his own. I like stuff that other people don't like too. My real point was that whatever you have should be fine unless you're looking to crawl specifically.

[4runner freak]

Well, If I ever get my 4runner out of the garage...
Mine will be 1st Tranny(L52) in Reverse(4.72) x 2nd Tranny(W56) in Reverse(4.091) x Stock T-case(2.28) x Diffs(4.30) = 189.31 : 1 :D

[xaza]

I have AW4 auto tranny 2.8:1, NP231 transfer case 2.72:1, Diffs 4.88:1 = 37.166:1 Crawl ratio. I do like to play on rocks and really need to get some skids, have none on now. I want to get a secondary low gear option only for rocks. By adding a second transfer case same ratio jumps me to 101.091, but only when I engage low gear in both transfer cases(can still switch back to 37). Also want to point out that these crawl ratios all are with low engaged so final gear ratio while in normal driving should be considered when planning gearing options as well as tire size. If the vehicle is driven on the road anyway.
also found this, might help someone


AX-5 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=293&type=2&ext=290893104224&item=290893104224)
3.93/2.33/1.45/1.00/0.85 with 4.74 reverse

AX-15 (http://viglink.pgpartner.com/rd.php?r=24566&m=1058124990&q=r&rdgt=1366291591&it=1366464391&et=1366896391&priceret=4.89&pg=%7E%7E3&k=a09d56478527625844b57fe08319fe67&source=feed&url=http%3A%2F%2Fwww%2Equikshiptoner%2Ecom%2Fcatal og%2Fbrother%2Dax%2D15%2Dcorrectable%2Dribbon%2D17 2yds&st=feed&mt=%7E%7E%7E%7E%7E%7E%7E%7En%7E%7E%7E)
3.83/2.33/1.44/1.00/0.79 with 4.22 reverse

NV3550 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=6000&type=2&ext=290801444095&item=290801444095)
4.04/2.33/1.38/1.00/0.78 with 3.75 reverse

NSG370 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=6000&type=2&ext=170859078147&item=170859078147)
4.46/2.61/1.72/1.25/1.00/0.84 with 4.06 reverse

[dscowell]

AX-5
3.93/2.33/1.45/1.00/0.85 with 4.74 reverse

AX-15 (http://viglink.pgpartner.com/rd.php?r=24566&m=1058124990&q=r&rdgt=1366291591&it=1366464391&et=1366896391&priceret=4.89&pg=%7E%7E3&k=a09d56478527625844b57fe08319fe67&source=feed&url=http%3A%2F%2Fwww%2Equikshiptoner%2Ecom%2Fcatal og%2Fbrother%2Dax%2D15%2Dcorrectable%2Dribbon%2D17 2yds&st=feed&mt=%7E%7E%7E%7E%7E%7E%7E%7En%7E%7E%7E)
3.83/2.33/1.44/1.00/0.79 with 4.22 reverse

NV3550 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=6000&type=2&ext=290801444095&item=290801444095)
4.04/2.33/1.38/1.00/0.78 with 3.75 reverse

NSG370 (http://rover.ebay.com/rover/1/711-53200-19255-0/1?toolid=10029&campid=CAMPAIGNID&customid=CUSTOMID&catId=6000&type=2&ext=170859078147&item=170859078147)
4.46/2.61/1.72/1.25/1.00/0.84 with 4.06 reverse

Thank you for the ratios I wasn't finding them on google or another fourm Im on

[dscowell]

So it is looking like my Crawl ratio is 31.98:1 so 32:1

[xaza]

this is pretty cool too
http://www.manoian.net/jeep/gear_ratio_calculator.html

[Squshiee1]

Trying to find a crawl ratio for a 97 isuzu rodeo. Priceless.:D

36.7:1

after sas/transfercase regear 86:1

[offroadwonder]

So by rough calculations based on factory numbers (4.17 first gear X 2.57 low range X 3.73 axle), my stock Tacoma can apply 10,633 ft-lbs torque across 4 tires :eek:. That seems like a HUGE number!

[Clickpopboom]

Math time: 3.75 1st gear * 4.10 low * 4.56 gears = 70.11:1

Explains why 2nd and 3rd gear see the most use in 4low.