front spring shackle question

[stice316]

I added longer shacles to my truck 83 toy with I think six inch springs and with the axel shims im having problems with the drive shaft. Curious if i need larger degree shims or if it would cause major problems to move the shackles to the front and mount the back solid. Thanks

[stice316]

total length of the shackle is 8" and at about a 30 degree angle

[DeadlyPeace]

Is this an DD or an trail rig?

I've heard of someone putting the shackles up front, but don't remember if he drove on the street or not. Jeeps are known for having the shackles in the front and seem to do fine So I think it would be ok as long as it's done right.

What degree shims do do have now? And what exactly is the problem with the DS? I'm guessing it's not long enough. If this is the case your best bet would be to just have the DS lengthened.

[fourwd1]

stice316 said:

I added longer shacles to my truck 83 toy with I think six inch springs and with the axel shims im having problems with the drive shaft. Curious if i need larger degree shims or if it would cause major problems to move the shackles to the front and mount the back solid. Thanks

OK, since no one else asked, what are the problems with the drive shaft ?

Can't answer the question properly if we don't know the problem.

[fourwd1]

Oh, and you don't want to put the shackles up front, a la Jeep.

Why do you think most Jeep owners do a shackle reversal so the shackle will be in the rear like a Toyota ?

[DeadlyPeace]

I've know of a lot of Jeepers doing the shackle reversal too, but always heard that it was just for better clearance. Is there more to it then that. Would be good to know.

BTW......

fourwd1 said:

OK, since no one else asked, what are the problems with the drive shaft ?

I did

deadlypeace said:

And what exactly is the problem with the DS? I'm guessing it's not long enough.

[fourwd1]

deadlypeace said:

I did

D'oh


Readers Digest version -

shackles at rear - as tire contacts object (rock), springs compress and axle moves rearward, tire goes up and over object,



shackles at front - as tire contacts object (rock), springs compress and axle moves forward, pushing you backward, instead of letting you go forward up and over



shackle reversal also helps reduce bumpsteer

NOTE - this is due to the seriously arched springs needed to lift a SUA j**p. It's not really an issue on a stocker.

[DeadlyPeace]

After reading that and now thinking about it, if I thought about the physics of it I could have realized that.......a-duh

Thanks for the explanation anyhow.

[stice316]

hey thanks for the response I think im just getting a little jumpy my d shaft problems are probably from me building it. Its been kind of a long winter here and cant wait to go wheelin again

[rockcrawlintoy]

you also bend springs often with a shackle in the front

[speedy]

You could always cut and turn your front axle to correct the pinion angle. A crapload of work but it kicks butt when done right. I did it with a big pipe cutter and alot of welding and grinding.

[Sean]

Im not quite getting this thread. Did you just buy some shims and throw them in there or did you measure your angles and degree it properly? Im assuming you are getting some noise out of your front shaft.

As far as shackles front or back they both have their advantages. I dont think the physics of it are quite that simple. One might argue the axle moves foward taking the tire with it getting you up and over the obstacle.

That debate aside the real advantage of having the shackles mounted up front is that the axle moves foward under compression keeping the tires out of the firewall. The firewall is the ultimate limit of tire size and flex unless you decide to move your steering box which in a lot of places can become a legal issue.
Advantage two is that as the axle droops the tire moves towards the transfer case instead of away from it. This means super long slip joints are not required to keep your driveshaft from falling apart under extreme flex.

[seth999]

I'm not exactually sure what type of problem you are having yet but if the drive shaft is binding up because of the angle or whatever the best way to fix it is not to use shims because they pop out if you really get in a good bind at least from what I'v seen...just cut the spring perches off order a new set (or reuse the old ones if your good with a P-cutter) and reweld them so the axle sits at the right angle for your rig plus it isn't that big of a job

[fourwd1]

sean said:

Im not quite getting this thread. Did you just buy some shims and throw them in there or did you measure your angles and degree it properly? Im assuming you are getting some noise out of your front shaft.

As far as I can tell, he hasn't really stated what the actual problem is, so there's no point continuing this guessing game.

[norcalyota]

I didn't read all the posts so not sure if someone mentioned this, but maybe you need a drop box up front to make the drive shaft angle correct.

[sookiesmacker]

deadlypeace said:

Is this an DD or an trail rig?

I've heard of someone putting the shackles up front, but don't remember if he drove on the street or not. j**ps are known for having the shackles in the front and seem to do fine So I think it would be ok as long as it's done right.

What degree shims do do have now? And what exactly is the problem with the DS? I'm guessing it's not long enough. If this is the case your best bet would be to just have the DS lengthened.

I've owned three jeeps, and I put a shackle reversal on all of them. The main reason people do this to jeeps is to keep them from roaming all over the road. If the swing shackles located in the front you get alot of bump steer and tire roam. If the solid mounts in the front it makes the jeep track alot truer. I'd leave it alone and lengthen the drive-shaft myself. JMO