Gearing and Crawl Ratio's

[johnpaulgolf]

Ok I've been doing some searching for the right set up for better "crawling"

I've been getting with Chuck about buying his axle's(which I will when he finds new ones) and kickin around new gears ect.

This is some info I've recently learned.


I now have a T-Shift D20 and a RAT 3 speed and 3.50 gears w/34"tires

Chuck has a NP435 with a J-Shift D20 and 4.56 gears w/ 38.5"tires

This is a PM I sent Chuck talking about my situation




I did some research...here is the numbers

RAT 3 speed 1st=3.41 2nd=1.86 3rd 1.00

NP435 4spd 1st=6.69 2nd=3.34 3rd 1.79 4th=1.00


T-shift D20 low=2.46

J-shift D20 low=2.34

so mine now = 29 to 1

my D20 w/NP435= 57 to 1 (real soon)ASAP

mine w/ 4.88 gears = 40 to 1

mine with your axles = 38 to 1

my D20 + NP435 with your axles = 75 to 1 (future mods)

yours now = 71 to 1


so you are the man again the cheapest fastest way to crawl will be the NP435 hands down.


thanks bro

[chuzie]

Do you already have a 235 or are purchasing one?

[johnpaulgolf]

I need to find a NP 435 not a 235...whats up stranger?

[66gasgrill]

If you run what I am you'll end up with 80 to one well 80.3. Np 435- 4.88 gears and 2.46 Tshift t-case. Don't forget to factor in you tire size also. This set up with 37's would be alot different than this set up with say 44's.

[johnpaulgolf]

If you run what I am you'll end up with 80 to one well 80.3. Np 435- 4.88 gears and 2.46 Tshift t-case. Don't forget to factor in you tire size also. This set up with 37's would be alot different than this set up with say 44's.

Thats sweet "gas" 80 to 1 is sick slow crawling.

How do the tire sizes affect the ratio's?

How do I put that(tire size) info in the equation?

[66gasgrill]

Tire size doesn't change your actual crawl ratio. It changes your effective ratio (what it feel like) if that makes sense.

Say your setup at 80:1 crawl. you will still have an 80:1 crawl ratio whether your running 31's or 44's but they won't feel the same. See what I mean kinda?

Check this site, maybe it explains it a little better. If not it still has some good info. HTH.

http://www.4lo.com/calc/geartable.htm

[High Pressure]

Tire size doesn't change your actual crawl ratio. It changes your effective ratio (what it feel like) if that makes sense.

Say your setup at 80:1 crawl. you will still have an 80:1 crawl ratio whether your running 31's or 44's but they won't feel the same. See what I mean kinda?

Check this site, maybe it explains it a little better. If not it still has some good info. HTH.

http://www.4lo.com/calc/geartable.htm

Don't know a great deal about this crawling stuff but that was well said..:xyxthumbs:

[SC74]

I always think of a 18 spd. bicycle when I think about gearing in a truck. That way you've got your 3 main gears (tranny, t-case, axles) plus 6 sub-gears (trans. gears, t-case high/low) on each main gear.

As for tire size, it takes more to turn the bigger meat. Just like on a bicycle, it takes more effort to turn a larger tire (especially off of the start) than it does a smaller one.

[broncomatt]

JP, I would go with lower axle gears. My rule has always been with 33" = 410 or lower, 35"=456 or lower and 38" and up 513 gears. I would not rely on trans and t-case just to make the ratio.
Just my 2c.
Broncomatt

[bucketobolts]

I started out with the NP435, a T shift case, 4.56's, and 35" tires. With the original 302, I could let the engine idle(800 rpm) in low gear low range, and it was hard to stall the engine with manual brakes. I had several stumps in the yard I used to play on by letting it idle up and across them.