Knuckle rotation
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Rotate the knuckles. Its not that hard and your toy will drive and handle
alot better than not doing it.
Bill
alot better than not doing it.
Bill
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462 Posts
The most important alignment setting on your front axle is castor. Draw a line from the top ball joint through the bottom ball joint and on to the ground. The angle that the line intersects with the ground is your castor angle. You want 4-6 degrees positive castor. Positive castor is when that line tilts towards the rear of the vehicle. Your castor angle will directly affect the handling characteristics of your vehicle - Return to center, wandering, death wobble, etc..
A little info on castor: http://www.melroset-tops.com/camber_castor_toe_defined.htm
That being said, rotating your knuckles will have no affect on the drivablility of your truck. Well, unless you totally botch the job and rotate each side differently
If you setup your castor angle correctly it won't matter how much you rotated you knuckles since the knuckles will end up in the same 'position'.
While it is commonly refered to as "Rotating the knuckles" because you are physically cutting the welds on the knuckles and rotating them on the axle tubes, in the end the knuckles don't move at all. It was the rest of the axle that actually got rotated. You could achieve the exact same affect by rotating the center chunk on the axle tubes, however its much easier to rotate the knuckles.
What you do gain by rotating your knuckles is:
1) Better pinion angle. This gets your pinion up and out of the way of things like rocks.
2) Better driveshaft angle. The front driveshaft is typically shorter than the rear and the more lift you have the worse the angle becomes. By pointing your pinion up at the tcase you put less stress on the ujoints and will have a much greater chance and being vibration free.
later!
shane
A little info on castor: http://www.melroset-tops.com/camber_castor_toe_defined.htm
That being said, rotating your knuckles will have no affect on the drivablility of your truck. Well, unless you totally botch the job and rotate each side differently
If you setup your castor angle correctly it won't matter how much you rotated you knuckles since the knuckles will end up in the same 'position'.While it is commonly refered to as "Rotating the knuckles" because you are physically cutting the welds on the knuckles and rotating them on the axle tubes, in the end the knuckles don't move at all. It was the rest of the axle that actually got rotated. You could achieve the exact same affect by rotating the center chunk on the axle tubes, however its much easier to rotate the knuckles.
What you do gain by rotating your knuckles is:
1) Better pinion angle. This gets your pinion up and out of the way of things like rocks.
2) Better driveshaft angle. The front driveshaft is typically shorter than the rear and the more lift you have the worse the angle becomes. By pointing your pinion up at the tcase you put less stress on the ujoints and will have a much greater chance and being vibration free.
later!
shane
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57 Posts
Hutch98 said:
I didn't rotate my knuckles and it drives fine. What Shane said is right on. All you are doing by rotating the knuckles is gaining a little clearance under the pumpkin and improving your driveline angle.
However, if you're getting the axle ready for a swap, why not do it? It's all the little extras that make the difference.
Rotating knucles shouldn't change the driveability of the truck, unless you do it wrong.
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I would rotate your knuckles. I have rotated knuckles on several different axles now and I would not do it any other way. The u joint angle is much better with the pinion rotated upwards. When you drop your driver side the pinion drops quite a bit changing the operating angle of your driveshaft ujoint. The less angle the stronger the joint. So if you start out with zero angle on the joint and flex it, your way better off then starting with 15 degrees of angle. I have to say that the driveshaft sits much happier with the pinion rotated upward.Hutch98 said:
I would also like to add that if your going to cut off the factory inner knuckles and rotate them. You might as well beef them up and replace them with the Crane Engineering Dana 44 knucles. I have bent an inner knuckle before and it sucks when you have to replace it. Crane sells them for $125 each and they are quite beefy.
As for driveability.... It will not make a difference if you set your castor correctly with the pinion rotated or no. I always set my castor at 6 degrees because I plan on the springs sagging a bit wich will decrease the castor. But... if you rotate the pinion up and then go with a CV joint driveshaft... your operation in 4 wheel drive will be much better than a non CV shaft and a bad pinion angle. My origional setup had a non CV drive shaft without the pinion rotated. I have very very bad vibes from my front shaft. So I rotated the knuckles and went with a CV type shaft. No vibes all the way up to 50mph! This is the main reason for rotating the knuckles.
Yogi
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295 Posts
How do I find out the stock castor on a D44 out of a Waggy? I know the old spring perches are for a spring under the axle set up but was wondering if setting the new spring perches the direct opposite as the old ones(on the top side of the axle) if that would maintain the stock castor? Just trying to get as many answers before the big day comes.
Thanks for the info
Hutch
Thanks for the info
Hutch
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145 Posts
When you rotate the knuckles, the main reason is to get the castor back at factory while pointing the pinion at the t-case. Not having the correct castor will affect your driving because if your castor isn't between 4-6 degrees, you won't be able to turn at all. Well, you can, but you won't be able to pull a uturn in less than 3 or 4 lanes. Also, your castor will affect bumpsteer, so if your castor is off, your bumpsteer will be bad. Rotating the knuckles can be quite a pain in the ass, depending on where you got your axles. Because I live in a humid environment, the knuckles on my d44 were so seized from rust it was ridiculous. I ended up using a hydraulic press to get one off, and a big ass hammer with a torch to get the other one off. On the other hand, I've had one where I ground the weld, and used a hammer and didn't even have to hit the knuckle hard to get it to move.
a friend of mine tried the no rotate method and ended up having to take his junk apart to rotate them when the truck was almost done, not the ideal time to make the call. even not worrying about castor we couldnt point the pinion at the t-case at all because his tie rod was hitting his springs, he was running the tall partsmike stuff too. i just rotated mine 1/4" and called it good, that should allow me to run a dual case set-up.
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114 Posts
Hutch98 said:
I use the the stock perch milled on the diff as a reference point. I figure how many degrees I want to rotate it, jig it up on my table at that angle, and weld the new perches level. Then I do one knuckel at a time and set it back to factory castor or a bit more. checkyour angles often, and you will come out fine.
you can always reference all your angles back to that milled perch to make sure your good to go.
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295 Posts
Just wondering if knocking back the knucle 1/4" would work? After the knucle is rotated is it easy to get your proper castor angle-- by placing the truck on the axle and spring perches find the pinion angle with the weight on the axle then tack the perches?
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6,547 Posts
Something I haven't really seen discussed in this thread is u-joints vs cv joints.
If you have a u-joint at each end of a driveshaft, the pinion and t-case output need to be parallel for a vibe free ride at anything more than low speed.
If you point the pinion straight at the transfer case, you'll need a u-joint at the pinion end, and a cv joint at the t-case to be vibe-free at higher speeds.
Later,
....Mike
If you have a u-joint at each end of a driveshaft, the pinion and t-case output need to be parallel for a vibe free ride at anything more than low speed.
If you point the pinion straight at the transfer case, you'll need a u-joint at the pinion end, and a cv joint at the t-case to be vibe-free at higher speeds.
Later,
....Mike
I have u-joints at each end, with the pinion pointed at the t-case, and a square driveshaft, I get no vibes except when climbing hills and the axle wraps down, recently in the snow/ice, I had it to 50 MPH in 4wd and all I heard was the 'slapping' of the driveshaft. No vibes... It makes more noise in 2wd, or when there is no torque going to the axle (throttle or brakes), but really doesn't vibrate unless I am wheeling and going up rather steep hills under throttle.Mike said:
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663 Posts
What Mike is saying is a fact, you are just a lucky SOB! Especially with a square driveshaft!!! A CV travels in a perfect circle where reg. u joints travel in an elipse...Tacoma747 said:
I am with BK005 on this one. I understand why it 'should' vibrate, and I even read about it before I rotated my knuckles, but seeing as most said the rotation needed to be done, I figured I would go ahead and do it. I knew I was going to use a square shaft, and was going to replace it with a CV shaft if it was needed and keep the square as a spare, but I don't have any problems with the square one so I will use what works and what is cheap
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