What's new
By:
Filters

Atlas 4speed gearing suggestions

Adolf Oliver

New member
Joined
Jan 8, 2023
Member Number
5918
Messages
1
Building a Rock bouncer INSPIRED rig....using 6.0LS, TH400, 14 Bolt, Super Duty D60....Looking for TRANSFER CASE RATIO RECOMMENDATIONS.... Going to use an Atlas, but trying g to decide on ratios....leaning towards the 4SPEED. We live in Nebraska and will travel to Colorado, South Dakota, Arkansas, Tennessee, Kansas, Oklahoma, Alabama, Utah, New Mexico, Etc, Etc....mostly a trail rig, but want a universally capable rig....roughly 122"-125" WB on 43" SX Stickies.....current axle ratio is 4:10 in the 14bolt and 3:73 in the D60....so gonna have to change 1 or the other at least...thinking of 4.3 Atlas with the Doubler and 4:10s, but wanna hear other ideas....
 
My favorite single speed ratio for what I do is 4.3:1. Seems to work great across a wide range of engine sizes tire sizes manual or auto and vehicle weights.

I also like options and a mid range for the nuisance areas between trails. My dream setup is 1:1 1.5:1 3.0:1 4.5:1. The 4.5 is close enough to the 4.3 for final low.

I have a 4 speed with 1:1 2.72:1 2.0:1 5.4:1. It’s a good case functionally but the ratios just don’t hit the sweet spots like I’d like.
 
JR4X said:
My favorite single speed ratio for what I do is 4.3:1. Seems to work great across a wide range of engine sizes tire sizes manual or auto and vehicle weights.

I also like options and a mid range for the nuisance areas between trails. My dream setup is 1:1 1.5:1 3.0:1 4.5:1. The 4.5 is close enough to the 4.3 for final low.

I have a 4 speed with 1:1 2.72:1 2.0:1 5.4:1. It’s a good case functionally but the ratios just don’t hit the sweet spots like I’d like.
Click to expand...

Atlas makes a 2.7/1.5 4 speed, which does come up at 4.05, so a hair short of your ideal case, but close.

I'm not sure I understand why you would need an 11:1 case for a "rock bouncer"

I'd think a 2.7/2.0 or 2.7/1.5 case would be closer to the debate.
 
The extreme end of the compouned function is not the goal in a bouncer.

Generaly they want the faster wheel speeds but if youre going 4spd you dont want redundant gears. You want 4 destinct speeds.
 
I’d personally go with 3.73 and the 10.34 gearing in a 4 speed with as much power as you have. your lowest crawl ratio is about 95:1, and when you want more go fast you will have about 35:1. I doubt you’d use 2.72:1 or 11.7 with 43s. Maybe you’d use 2.72 instead of 3.8. The reason I’d go 3.73 is because it is probably easier to setup gears in a 14 bolt with a removable third member than dropping in a carrier multiple times.
 
95:1 is pretty damn low for an auto in a rock bouncer no? I'm betting most are running around 30-40:1 and the big boys racing are probably more like 10-20:1
 
Bouncer inspired styling or driving?

Definitely lower axle gearing. 5.xx at least.

From a handling standpoint, you want to do the reduction in the axle instead of the tranny/t-case. Less torque roll.

With that wheel base, is it a 4 seater or modified Jeep/truck? Or are you building a long 2 seater?
 
Treefrog said:
Bouncer inspired styling or driving?

Definitely lower axle gearing. 5.xx at least.

From a handling standpoint, you want to do the reduction in the axle instead of the tranny/t-case. Less torque roll.

With that wheel base, is it a 4 seater or modified Jeep/truck? Or are you building a long 2 seater?
Click to expand...

I was going to say this too. I'm not sure why you wouldn't go to 5.13s if you're thinking about a $5k tcase.
 
You must log in or register to reply here.
Top Back Refresh