Topic: whats my crawl ratio?

[toygasm]

i was showing a guy how slow my truck is and he asked me what the crawl ratio was.i wasnt sure and really never gave it much thought.i just watched the video of big mikes truck doing his slow motion brake stand and it got me wondering....ive got a marlin built w56,marlin duals 2.28/4.7 and 529s..obviously a very common setup.

[BigMike]

Hey toygasm,

Calculating your Crawl Ratio is a matter of knowing each gear reduction between your engine and your tires and then multiplying them together.

Transmission:
To check what gear ratio your have, use our chart here: http://www.marlincrawler.com/tech/transmission/transmission-gear-ratio-chart

Your W56 has a 3.95:1 first gear.

Crawl Box:
Your Crawl Box is the 2.28:1 unit

Transfer Case:
T/Case has the 4.70s

Axles:
Axles have 5.29:1

Crawl Ratio:

Transmission X	Crawl Box X	Transfer Case X	Differential	=
3.95	2.28	4.70	5.29	= 223.91:1 or 224:1 Final Drive (or Crawl) Ratio.

You've got what we call the Ultimate Ratio which you can read more about here: http://www.marlincrawler.com/java/ultimate.html

Here is another example of what your Crawl Ratio is in 2nd gear:

2nd gear X	Crawl Box X	Transfer Case X	Differential	=
2.14	2.28	4.70	5.29	= 121:1

And continuing, we see your 5th gear is 48.2:1 which is what your truck was before the Marlin Crawler, 47.6:1. So our Marlin Crawler turned your old first gear into your new fifth gear!!

We have an old online Crawl Ratio Calculator here that you does all the calculations for you: http://www.marlincrawler.com/java/getratio_calc.html

...and we also have an old Vehicle Speed Calculator here: http://www.marlincrawler.com/java/getspd_calc.html which you can enter your tire size and engine rpm (assume 800 rpm for idle speed) to see how fast your truck is actually moving.

The Vehicle Speed Calculator shows that Marlin's truck moves 0.0641 miles per hour in first gear, or 15.6 hours per mile!!


BigMike

[BigMike]

I just updated the Vehicle Speed Calculator to show the MPH inverse which is HPM. I haven't updated that file since I think the 90s!! (I made it while I was still in high school). I used Javascript and I hate Javascript. I'm much better at PHP... I think I may have to create new modern versions of these Calculators

* BigMike thinks about how much stuff he has on his todo list

[toygasm [OP]]

thanks for the info.

[dweinberg01]

Does anyone know what first gear for an A340h is?  I know you double it because of the torque converter then go about multiplying as you go back.  I just can't find my trans 1st  gear. thx

A340h first gear x marlin dual ultimate x 4.88 r&p = ~340:1 I'm thinkin.

[TimberlineBryce]

This is so awesome!! Where do I find my R150f trans 2nd thru 5th gear ratios??

[Nimyad]

That's fun to play with.

[BigMike]

Does anyone know what first gear for an A340h is?

Lately I've been using Wikipedia for automatic transmission ratios. Check here: http://en.wikipedia.org/wiki/Toyota_A_transmission#A3xx They are not all listed but it should be a good place to start.

I know you double it because of the torque converter

This is correct. I've heard Torque Converters range from 2:1 to 2.5:1 reduction.

This is so awesome!! Where do I find my R150f trans 2nd thru 5th gear ratios??

Clicky: http://www.marlincrawler.com/tech/transmission/transmission-gear-ratio-chart

BigMike

[dweinberg01]

Lately I've been using Wikipedia for automatic transmission ratios. Check here: http://en.wikipedia.org/wiki/Toyota_A_transmission#A3xx They are not all listed but it should be a good place to start.
This is correct. I've heard Torque Converters range from 2:1 to 2.5:1 reduction.


BigMike

This is what i got: 366.05856 :1.  Not bad!!! Thanks for the info BigMike

[BigMike]

That is incredibly great for an Automatic! I bet you have trouble stopping it sometimes even!! I love it!!!

[TimberlineBryce]

So if I did the math crrrectly, when I put the single 4.7 t-case in, my first gear should be about double what my stock first is now and my 4.7 5th gear will be about halfway between my stock second and third gear(which should be perfect for cruising the easy stuff). This is exciting because I was worried I wouldn't be happy with this setup like everyone has been telling me but with using the math it sounds like it'll be exactly what I'm looking for;))

[BigMike]

Here are some prehistoric videos comparing different Crawl ratios:

http://www.marlincrawler.com/video/index.php

[TimberlineBryce]

Hey Mike how did you get 511:1?? And what gear ratio do you find yourself using most often on the trails around here??

[TimberlineBryce]

My first gear final will be 82:1 which I think will be ok for most "on-trail" wheeling in this area...

[BigMike]

Hey Mike how did you get 511:1??

3.95:1 W56-A transmission > 2.28:1 Crawl Box > 2.28:1 Crawl Box > 4.70:1 Transfer Case > 5.29:1 Differential: 510.53:1

And what gear ratio do you find yourself using most often on the trails around here??

I just got back from Dusy and we were jamming most of the time because we were short on time (went from Thompson Lake back to the Pavement at Courtright in 2-1/2 hrs).
On the easy sections I was in single 2.28:1 using 1st-3rd gears.
On the moderate sections I was in Dual Stock 2.28 + 2.28 using 1st-2nd gears.
On the difficult sections I was in Dual Ultimate 2.28 + 4.70 using 2nd-4th gears (Out of luxury, I never use Dual Ultimate 1st gear, I explain why below).
And twice I needed really precise control so I used Triple Ultimate 2.28 + 2.28 + 4.70 and 2nd gear (I used it while coming down Thompson when I had to backup; I used it near Dusy Meadows when a rock got wedged between my beadlock ring and my hub). I never used any other gear in Triple Ultimate.

The gears I use most of the time on our local trials would be Dual Stock 2.28 + 2.28 using 1st - 3rd gears. I only shift back to a single 2.28 if I am using 4th or 5th gear in Dual Stock (because it's pointless to spin the transmission that fast when I can just simply shift back to a single 2.28 case).
My overall favorite gear ratio I have, regardless of the trail, is Triple Ultimate 2.28 + 2.28 + 4.70 in 2nd gear. This gear (277:1) is about 25% lower than a Dual Ultimate's first gear (224:1) and that little extra bit allows me to lug down to about 400 rpm without stalling the engine. I almost never use my Triple Ultimate 1st gear. It is my only novelty gear ratio and I only use it to demonstrate the power of the Marlin Crawler.

BigMike

[TimberlineBryce]

Lol "novelty gear"!! I like that! ok good info, thanks!

[ImmortalYota80]

This was helpful