PDA

View Full Version : ? about Pinion Angle/Wheel Base.....



LittleBeast
02/24/2010, 11:43 AM
As we lift higher and higher with the suspension lifts on the rear of the VX, the rear tires start getting closer and closer to the center of the VX and thus the tire is no longer in the middle of the wheel well, but rather almost rubs on the front side of the cladding. Basically the higher the rear goes the closer the tires are to the front cladding.

To fix this we need adjustable links correct? :

https://www.independent4x.com/merchantmanager/product_info.php?products_id=50

https://www.independent4x.com/merchantmanager/images/uploads/xtreme%20duty%20upper.jpg

https://www.independent4x.com/merchantmanager/product_info.php?products_id=49

https://www.independent4x.com/merchantmanager/images/uploads/98RodeolinksADJUST.jpg

You can see the 3 items I am referring to in the middle of this kit, the short link directly in the middle and then the very long links surrounding the kit (vertically placed) are what I think we need for this right? Not the HD (red) torsion bars, but the silver links:

https://www.independent4x.com/merchantmanager/images/uploads/proelite92+trooper.jpg

Quote from Idependent 4x on these items: "adds the big benefit of pinion angle & wheel base adjustments needed after lifting!" This is what I am looking for correct? I know the picture they use for the lower adjustable links is not to scale they are actually a lot longer than shown, but you can see them in the last kit photo. Trying to push those rear tires back to the center of the wheel wells after lifting correct? I think our rear drive shaft should extend another 1" or so back to handle this, correct?

tom4bren
02/24/2010, 02:19 PM
I really can't answer your questions. I do know that the calmini lift on the rear of mine came with a panhard rod drop. I think it just re-centers the axle after the lift tho & doesn't do anything to fix the change in track of the rear tires.

Triathlete
02/24/2010, 02:43 PM
Another option is to take your links to a local 4x4 fab shop. They can cut the ends off, sleeve the current tubes to add some beef and lengthen them to the desired length and re-weld the stock ends back on. As T4B said, with as much lift as you have your wheels are also going to be off to one side a bit. You can also have them fab up a relocation bracket for the panhard bar to re-center your rearend.

ZEUS
02/24/2010, 04:54 PM
Those links would indeed move the axle rearward. An issue could arise with the axle making contact with the fuel tank upon upward travel though. You'd just have to see how close the diff is to hitting the tank beforehand while the suspension is compressed to gauge how far back you could move it. Replacing only the upper link with a longer option will lift the pinion to lessen the angle of the driveshaft and slightly move the axle rearward. That should remove the need for a lengthened driveshaft and give a slightly better axle placement at ride height without switching out the lower arms. I think that twist might tweak the panhard bar a bit however... it would probly still work tho. Consider also the more you move the axle to the rear the further back it is when it flexes into the wheelwell.

Jay Dunford
02/24/2010, 05:08 PM
Another thing to look for is where your slip yoke on the rear driveshaft is. It pulls apart further the higher the lift and if you keep the downtravel with longer shocks/springs it can get far enough down the splines to lose strength or even come apart. I don't think you're going high enough to worry, but it is something to check. The front driveshaft CV's really don't like high pinion angles so a diff drop via bracket modification as seen on several threads is highly advisable, this helps with the angles on the axle CV's too. The pinion angle can also be adjusted with the diff drop by realigning the diff mounting holes a bit to tilt the pumpkin up a few degrees. Any good fab shop should be able to handle this.

LittleBeast
03/03/2010, 04:26 PM
I just got the phone with the guys at Indy4x and YES if you want to change your wheel base by up to 3" you would just want to buy the rear adjustable upper link ($220) and rear lower adjustable links ($460), actually they have over 4" of adjustment, but he said you would not want to adjust over 3", I am thinking I only need about 1-1/2" or 2" anyways.

This will in fact push the rear tires back in the rear wheel well, and you can also adjust your pinion angle which is basically where your rear diff is pointing and thus how much of an angle your u-joints on your axle have to handle. I look forward to this mod soon. Under $700 to move your rear tires and better align your rear diff to axle. I can't wait :happyface

tom4bren
03/04/2010, 07:14 AM
Rotating the pumpkin will help with the angle but it puts the U joints on the drive shaft at different phase. A little is acceptable but you can end up doing more harm than good.

MSHardeman
03/04/2010, 08:38 AM
Beast, I don't know how to look out for this, but a former member (Bimati) did a lift on his VX and I thought that he started to chew up drive shafts. It may have actually been the half shafts, and I may be mis-remembering here, but I remember him saying something about the pumpkin angle being critical. If it's tilted to far forward or backwards it starts to screw things up.

I'll try and hunt down some threads about this, but that's what my rusty steel trap of a mind seems to remember.

Triathlete
03/04/2010, 12:59 PM
The angle of the pinion should remain the same on a linked suspension as the suspension travels up/down. The joint on the TCase side is were to run into problems with essesive lift. A custom high angle drive shaft can alleviate this.

LittleBeast
03/05/2010, 11:11 AM
The angle of the pinion should remain the same on a linked suspension as the suspension travels up/down. The joint on the TCase side is were to run into problems with essesive lift. A custom high angle drive shaft can alleviate this.

True true, but if you use the lower links to push the tires backward in the wheel well, you need to use the upper link to angle the pinion back to the stock angle.

Ldub
03/05/2010, 11:42 AM
Beast, I don't know how to look out for this, but a former member (Bimati) did a lift on his VX and I thought that he started to chew up drive shafts. It may have actually been the half shafts, and I may be mis-remembering here, but I remember him saying something about the pumpkin angle being critical. If it's tilted to far forward or backwards it starts to screw things up.

IIRC, a contributing factor to the problems that Jeff was having , was the use of wheel spacers to make GM wheels fit...:confusedw