6" Rough Country Lift 1982 Flareside

[old55pete]

Dave, its still the stock geometry, just spaced 6". The rear axle lift blocks correct the pinion angle to prevent driveshaft bind.

Not sure how the pinion angle is set on the front, but I suspect the radius arm bushing holes in the new drop brackets are located in relation to the new axle pivot drop brackets in order to maintain the pinion angle. They do recommend new eccentric bushings for chamber adjustment.

A quick way to find your drive line angle is to use a magnetic angle finder, make sure the truck is level then put the weight on the suspention and put the angle finder on top of the drive line and the other side to the top of the yoke where the u joint cap sits in. It is my understanding that u joints were only ment to run for a short peroid of time at 17 or over degrese and will start binding. This is why the shorter wheel base Broncos have a double cardigan( spelling) joint at the t case.

[Ray Cecil]

Ray,

You didn't space the transfer case down 6".

If A remains the same

And B increases 6"

Then C has to increase in accordance *with Pythagorean theorem.

I understand that the "C" or hypotenuese gets longer. This driveshaft has a slip joint long enough to account for the change (I think/hope).

What we are really concerned about is not C. We are concerned with the pinion angle at the front diff, and at the tcase. Once I have it all together I will find a flat spot somewhere and measure the angle of the dangle. Ha

[ArdWrknTrk]

Ray,

You didn't space the transfer case down 6".

If A remains the same

And B increases 6"

Then C has to increase in accordance *with Pythagorean theorem.

I understand that the "C" or hypotenuese gets longer. This driveshaft has a slip joint long enough to account for the change (I think/hope).

What we are really concerned about is not C. We are concerned with the pinion angle at the front diff, and at the tcase. Once I have it all together I will find a flat spot somewhere and measure the angle of the dangle. Ha

I guess I misinterpreted What Dave was saying about limit straps.

If this conversation has gone to drive angles, be aware that the universals at each end should be at the same angle or they will be out of phase and binding.(minutely, a couple of times every revolution)

Not that it will stop them, but it will wear them prematurely.

This is why CV joints have gained popularity.

Gary can offer a bit of background, from when he was questioning why he needed (wanted) the double cardan front driveshaft that comes with a D60.

There is really no way to change the transfer case output, so that double cardan is used to bisect the angle. Also in the driveshaft of Broncos...

Edit: We've all seen mall crawlers and brodozers with the pinion pointing right at the TC output.

This is exactly what you DON'T want.

Zero angle in one joint and all the angle in the other.

You would be better off with full angle in both (to the limit) because at least both ends of the shaft would be trying to go the same speed.

[Ray Cecil]

I guess I misinterpreted What Dave was saying about limit straps.

If this conversation has gone to drive angles, be aware that the universals at each end should be at the same angle or they will be out of phase and binding.(minutely, a couple of times every revolution)

Not that it will stop them, but it will wear them prematurely.

This is why CV joints have gained popularity.

Gary can offer a bit of background, from when he was questioning why he needed (wanted) the double cardan front driveshaft that comes with a D60.

There is really no way to change the transfer case output, so that double cardan is used to bisect the angle. Also in the driveshaft of Broncos...

Edit: We've all seen mall crawlers and brodozers with the pinion pointing right at the TC output.

This is exactly what you DON'T want.

Zero angle in one joint and all the angle in the other.

You would be better off with full angle in both (to the limit) because at least both ends of the shaft would be trying to go the same speed.

I guess what I should do is call Rough Country, and ask them about the design.

Just inspecting the rear, the lift blocks have corrected the diff pinion angle.

I highly doubt that the radius arm brackets and the pivot brackets all have dropped straight down 6". How else will they have accounted for the pinion angle? Im willing to bet the radius arm brackets are where the magic happens with the geometry. Looking at the control arm pivot brackets, they do appear straight down from the original position.

Limiting straps might be a good idea if I go wheeling, probably not necessary for the street though.

[ArdWrknTrk]

I guess what I should do is call Rough Country, and ask them about the design.

Just inspecting the rear, the lift blocks have corrected the diff pinion angle.

I highly doubt that the radius arm brackets and the pivot brackets all have dropped straight down 6". How else will they have accounted for the pinion angle? Im willing to bet the radius arm brackets are where the magic happens with the geometry. Looking at the control arm pivot brackets, they do appear straight down from the original position.

Limiting straps might be a good idea if I go wheeling, probably not necessary for the street though.

Dave did some off-road racing so I'm sure he knows about droop while airborne.

Pinion angles are simple geometry.

Since you have access to powerful and dynamic CAD you could model the U-joints and fixed yokes at each end of a ridgid shaft and watch the acceleration and deceleration as the shaft and yokes rotate.

I'm sure you have a library full of this stuff?

[Ray Cecil]

Dave did some off-road racing so I'm sure he knows about droop while airborne.

Pinion angles are simple geometry.

Since you have access to powerful and dynamic CAD you could model the U-joints and fixed yokes at each end of a ridgid shaft and watch the acceleration and deceleration as the shaft and yokes rotate.

I'm sure you have a library full of this stuff?

I wish I had time to play with CAD like that. But yeah, I could do it. Too many other things going on.

[ArdWrknTrk]

I wish I had time to play with CAD like that. But yeah, I could do it. Too many other things going on.

Maybe you have a little time to read what experts have to say?

https://4xshaft.com/blogs/general-tech-info-articles/tail-shaft-conversion-kits

https://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php

https://www.therangerstation.com/tech_library/pinionangles.shtml

Spicer/Dana also have pages and pages, but I can't link pdf's from my phone.

[Ray Cecil]

Maybe you have a little time to read what experts have to say?

https://4xshaft.com/blogs/general-tech-info-articles/tail-shaft-conversion-kits

https://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php

https://www.therangerstation.com/tech_library/pinionangles.shtml

Spicer/Dana also have pages and pages, but I can't link pdf's from my phone.

Jim, thanks for the links, I'll check them out.

I did some measuring. The axle pivots are 6" straight down drop. That makes sense.

The radius arm pivot brackets are closer to 5" lower than stock. This must be how the kit corrects the pinion angle. However, this effects caster. Which is why they recommend new adjustable ball joint bushings to correct this.

The rear drive shaft has extended about 1.5", just eyeballing the slip joint. I have no idea how long the splines are.there is no slop in the joint.

I was succesfull removing the 1st eccentric bushing without removing the knuckle. I made a quick Youtube vid to show yall.

[ArdWrknTrk]

Jim, thanks for the links, I'll check them out.

I did some measuring. The axle pivots are 6" straight down drop. That makes sense.

The radius arm pivot brackets are closer to 5" lower than stock. This must be how the kit corrects the pinion angle. However, this effects caster. Which is why they recommend new adjustable ball joint bushings to correct this.

The rear drive shaft has extended about 1.5", just eyeballing the slip joint. I have no idea how long the splines are.there is no slop in the joint.

I was succesfull removing the 1st eccentric bushing without removing the knuckle. I made a quick Youtube vid to show yall.

Well that's real cool how your pitman arm puller fits nicely when you relieve the octagon (?) at the top of the bushing.

You can also hear it coming right out of there.

I can almost guarantee that if Angelo or I tried that we'd be there with a torch and a hammer.

Looking good.

Hope you enjoy the additional ride height!

 

[Gary Lewis]

Jim, thanks for the links, I'll check them out.

I did some measuring. The axle pivots are 6" straight down drop. That makes sense.

The radius arm pivot brackets are closer to 5" lower than stock. This must be how the kit corrects the pinion angle. However, this effects caster. Which is why they recommend new adjustable ball joint bushings to correct this.

The rear drive shaft has extended about 1.5", just eyeballing the slip joint. I have no idea how long the splines are.there is no slop in the joint.

I was succesfull removing the 1st eccentric bushing without removing the knuckle. I made a quick Youtube vid to show yall.

I like that, Ray. Worked very nicely.