crawl ratio

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[navman 5.0]

Well after this sundays damage, it's time to build the new front axle. I can't decide on what to do for gearing. Right now I have 37" tires, a 2.72 low range, a 6.68 first gear and 4.10 ring and pinion. This gives me a 74.5:1 crawl ratio. Second gear is 3.34 giving me a 37.25:1 crawl ratio and is about a thousand rpm less than first at the same speed. I want a bit more for crawling, but don't want to go overboard especially with the big swing between gears. What do you guys think?

[Ian]

when i was looking into crawl ratio's it seemed that 90-100 was a good new england ratio, especially for non buggies.

[navman 5.0]

4.88 gears would put me at an 88.67

[jps4jeep]

go 4.88, will be nice with the slightly deeper ratio, but you will still have 2nd for wheel speed

[Ian]

what is the new front axle going to be?

[navman 5.0]

Well you know I won't be happy till everything on this rig is Ford 
Spider 9 with a truehi9 chuck. Thats why I need to decide on gears right now so I can get the center ordered up.

[Ian]

Well you know I won't be happy till everything on this rig is Ford 
Spider 9 with a truehi9 chuck. Thats why I need to decide on gears right now so I can get the center ordered up.

spiffy.  what will be your weak link now?  t-case? 

[jason m]

Well coming from driving a Auto for years I kinda forgot what gear on gear crawl ratio is like. I'm used to a T/C ( tourqe convetor ) doing the crawl for me. But I lack deeper gears ( for now ) and really push the engine sometimes to make a decent crawl happen. I'm to the point were I use the brakes to help keep my crawl ratio down so I can keep wheel spin from happing.
This was Miguels small probalem at Adams house over the weekend, he used more throttle than his crawl ratio. Me I'm only 36-1 but the T/C nearly double's that. But the more I use that T/C the more heat I build.

For stick, I allway feel lower the better. You can allways up shift. Really I'm not the guy to speak much on the topic as like I said I deal with a slush box.
I know that the buggy I borrowed over the weekend it had a 5.0 atlas, a TF904 witch is a 2.76 first gear and 4.10's in the axle. It crawled so well, very little brake action was needed for me to work it threw some hard spots, even one spot were I was completely on my side with Miguel allmost fallen out of his seat. But comparied to my Jeep it was unreal how a lower crawl Auto was worlds better.

So what would 5.13's give you. Do you plan to keep the stick or will you ever upgrade to a C6. If you did then the deeper gears now will benifit later if you did swap to a slush box.

Jason.

[navman 5.0]

5.13 would put me at a 93.21, and add another 100 or so rpm, so not a whole lot different. I don't think I would ever go auto, I know there are advantages, but I like the challenge of the stick.

[jeepgod]

swap in 5.13 gears, you will never regret it. the amount of control off road will be amazing for you. i speak from experience. i went from about 38 to 1 to 89 to 1 and then to 147 to 1 and have never thought "boy wish i had a worse crawl ratio"

[mika401]

Todd's right after wheeling Adam's property this past Sat my 4.10 gears just dont cut it!  2.45x4.3x4.10 = 43/1 not enough.

Yesterday I ordered up some 5.13 gears from ECGS, $400 total shipped to my door for the front & rear which will give me 2.45x4.3x5.13 = 54/1 much better!

Go low you wont regret it in the highly technical areas

[navman 5.0]

So yesterday I ordered up the hi9 with 5.14 gears. This will put me at a 93.21 first gear crawl ratio, gaining almost 200 rpm at the very bottom over my current setup. 2nd gear will give me a 46.61 CR which is still numerically higher than what I had with 1st gear on the original 4cyl/35" setup so that should still work on the easy stuff. Thanks for the input guys. Now I need to find a strong set of gears for the rear.

[jason m]

Todd's right after wheeling Adam's property this past Sat my 4.10 gears just dont cut it!  2.45x4.3x4.10 = 43/1 not enough.

Yesterday I ordered up some 5.13 gears from ECGS, $400 total shipped to my door for the front & rear which will give me 2.45x4.3x5.13 = 54/1 much better!

Go low you wont regret it in the highly technical areas

Add the right amount of fluid in one's tranny also for the technical areas to

Jason.

[Twisty]

I'm at 40:1 if you do NOT count for torque converter slip.  Probably around 60:1 or 70:1 if you DO account for slip. 

With the 42s, I wish it was deeper.  I'm really looking forward to getting my doubler (4:1 low-low) in.

My trans is 2.8:1, my transfer case is 2.72:1, and my axles are 5.38:1.

[jps4jeep]

after build I'll be 112.1 assuming I run 42" tires.
right now I am 51.1 but witht the doubler I'll have options in between