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Crawl Ratio vs the Terrain
Topic Started: Sep 6 2011, 07:23 PM (908 Views)
oldtime
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Simply asking of your opinions.

What kind of terrain do you 4 wheel in and what crawl ratios do you find to be most useful ?
What crawl ratio is definately too high for your driving conditions ?
What crawl ratio is definately too low for your driving conditions ?
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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tow hook
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tow hook, your western pa jeep guy
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To find your crawl ratio try: http://www.novak-adapt.com/knowledge/gearing.htm

for me (t-90c) 3.49 X (dana 18) 2.46 x (diff ratio) 5.38 = 46

what i want 3.49 x (d-18 tera low kit ) 3.15 x 5.38 = 59

with the warn o/d, the tera low kit would more useable, and i would have 6 forward gears :) for me i do trails, and rocks. mud bad :)

to low for me, the t-90a x (dana 20) 2.01 x 5.38 i'd be in the upper 20's low 30's

to high would be a np435 x dana 18 tera low kit x 5.38 i'd be close to 90 to 1 things would start to break..

hope this helps :D
57 3b now a trans model 3b :)
93 xj r.i.p.
95 yj 33's daily driver
02 wj 33's wifes rig
98 xj rock crawler wanta be
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Dougie
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Trips to the garden shop, the main use of my Heep, don't require much of a crawl ratio. I find that the stock low range and 7x15 tires are fine for everything I have tried. But I'm not into serious rock-climbing anyway.

One thing I learned from Sammy Miller back in the 1970s when I was riding trials motorcycles was that low gear is generally not what you want. In most cases, the tires will slip before you can get that much torque down anyway, so it's usually better to just go a bit faster in a higher gear. The professional trials riders at that time rode the sections FAST, and it's only fairly recently since trials became a stunt riding exercise that the really low gears were useful...

Like this--although this newfangled business about coming to a complete stop would be considered a fail, back in the good old days...

http://www.youtube.com/watch?v=hfVUD1JYuWo&feature=related
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Bob_webber
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for my B the stock 2.46 to 1 does great, however navigating a rocky creek, trail, backing a trailer through a very tight spot, or tugging and pulling in a very hairy situation i might not mind having an extra option. i agree with tow hook the t-90 c with the tera low and an all range od would be the optimum. rocks and very rough areas are mostly when you will need it. you also might consider your wheelin buddy if he has high gears and is following you he might not be a happy camper, or vice-versa.
53 3b, early cj5 frame (hurricane),2.43 ratio t case 26 tooth with 1 1/4" case (my own creation), late 60's c5 ross steering box, all range od, parts from a welder generator, and parts from about 9 different jeeps and counting. my every last penny and ounce of patients creates what we call the FrAnken B, the jeep that never was

bob, north east Ohio
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oldtime
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T90 C = 3.339 first gear ratio
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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tow hook
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tow hook, your western pa jeep guy
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Dougie,Sep 7 2011
06:03 PM
Trips to the garden shop, the main use of my Heep, don't require much of a crawl ratio. I find that the stock low range and 7x15 tires are fine for everything I have tried. But I'm not into serious rock-climbing anyway.

One thing I learned from Sammy Miller back in the 1970s when I was riding trials motorcycles was that low gear is generally not what you want. In most cases, the tires will slip before you can get that much torque down anyway, so it's usually better to just go a bit faster in a higher gear. The professional trials riders at that time rode the sections FAST, and it's only fairly recently since trials became a stunt riding exercise that the really low gears were useful...

Like this--although this newfangled business about coming to a complete stop would be considered a fail, back in the good old days...

http://www.youtube.com/watch?v=hfVUD1JYuWo&feature=related

cool video, i rode a betta when i was unyounger..i now weigh more then the betta :( .. lol
57 3b now a trans model 3b :)
93 xj r.i.p.
95 yj 33's daily driver
02 wj 33's wifes rig
98 xj rock crawler wanta be
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tow hook
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tow hook, your western pa jeep guy
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Bob_webber,Sep 7 2011
07:03 PM
for my B the stock 2.46 to 1 does great, however navigating a rocky creek, trail, backing a trailer through a very tight spot, or tugging and pulling in a very hairy situation i might not mind having an extra option. i agree with tow hook the t-90 c with the tera low and an all range od would be the optimum. rocks and very rough areas are mostly when you will need it. you also might consider your wheelin buddy if he has high gears and is following you he might not be a happy camper, or vice-versa.

thanks for the words :) i like having control over the rocks, and not being as young as i was, the control helps come the next morning. to bad they don't have coils. i'm more of a rock guy, so just about all my jeeps have a regear done to them, or a reduced range t-case. to high a gear, and i've stalled out trying to climb a tree stump. i like to be able to select my gear, no gas, no clutch no brake just drive. a hand throttle comes in nice here as well :)

most under kids don't under stand (when i try to follow them on fire roads in my yj) that it's not fun, and coils ride nicer, hence they go faster...
57 3b now a trans model 3b :)
93 xj r.i.p.
95 yj 33's daily driver
02 wj 33's wifes rig
98 xj rock crawler wanta be
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williams3b54
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I believe my 54 HH has all of the original gear ratios that were produced in the T-90 3.39, the transfer case is also stock gearing, but I have a Husky overdrive on the back of the transfer case and I do have six gears forward and two in reverse. I have 33" tires on the Dana 44 rear with 5:38's and of course on the front dana 25 ( open ) I wheel in the Washington Cascades a lot and in Idaho. What I have found is the OD is great splitting the gears in 4 wheel drive conditions. First OD lets you go up and down in the first gear without double clutching the tranny. The one draw back with my ratios is decending some of the steep hills in the Cascades. Not quite low enough to let you decend slowly without using the brakes. I have learned to overcome the disadvantage though.
When we wheel in the mts. the air pressure is dropped to about 8 to 10 psi. and that does help with the rolling speeds on the trails. And of course it provides a bunch more traction. I do not have any problems with the gearing I presently have in a fairly original running gear. I do have a 'power-lock' in the Dana 44.
This 54 HH has done the trails in MOab with the drive train like I have described. I am not much into "rock crawling"
Dick W.
1954 CJ-3B
Semi-modified for trail riding in the Northwest.
See photos on CJ-3B page owners photos 1954.
1968 CJ-5/1975 231 odd fire V-6/ many other mods. ordered new from Toledo 1968.
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oldtime
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Dick,
The 1954 will have a T90 A with 2.798 first gear. (2.8 ratio)
Post 11/1962 CJ's have a T90 C with 3.339 first gear (3.34 ratio)

In mid year 1954 Jeeps began using the 2.46 ratio transfer case.
CJ's from 1945 through 1953 used the 2.43 ratio transfer case.

One can effectively turn a T90 A into a T90 C by changing the maindrive and countershaft gear.

As always thanks for posting !
Currently building my final F-134 powered 3B .
Rock Crawler using factory parts from the Willys Motors era (1953-1963)

http://s4.zetaboards.com/CJ3B_Bulletin_Board/topic/30228766/1/#new
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