Centered axles and driveline angles

[AndyG]

A while back I was sorting out a driveline vibe after new rear springs, and my drive line guy basically said-

" Make sure your axles are centered -if not, you are introducing another angle into the driveline".

Recently there was a thread on an axle being off center and a lot of posts said not to worry about it.

What the driveline shop said to me seemed to make sense- albeit I know it would not be much angle.

Also, this shop is so experienced with TJs they won't even talk about vibes with their shafts if you have urethane transmission mounts ...and they know exactly what's going on when you tell them how you are set up, as far as angles, and even rear track bar clearance and all the things we deal with...pretty cool. Seems they know every peripheral factor.

What do you guys think about axle center adding another driveline angle?

 

[Chris]

Are we talking about the axles being centered laterally or centered within the wheel well?

I could see how an axle that wasn't centered laterally could potentially introduce another angle to the driveshaft, but unless it's a 6" lift with stock track bars, I don't see there being any issue.

 

[AndyG]

Are we talking about the axles being centered laterally or centered within the wheel well?

I could see how an axle that wasn't centered laterally could potentially introduce another angle to the driveshaft, but unless it's a 6" lift with stock track bars, I don't see there being any issue.

Well , I think he meant if the entire axle is pushed to one side as a lift does , the shaft then has that angle also. That was my take on it.

 

[Chris]

Well , I think he meant if the entire axle is pushed to one side as a lift does , the shaft then has that angle also. That was my take on it.

That's what I figured.

And at 8" of lift (or something absurd) with factory track bars, that's going to be a huge issue not just for your driveshaft angles, but also for your steering and such.

But at 2" of lift it shouldn't be an issue whatsoever. The axles will be off center laterally, but likely no more than 1/2" give or take.

 

[Blackjack]

Compound angles just make getting a driveshaft to its happy place more complicated that is all. Anyone who does an 8.8 swap learns this. This is one of the reasons for a running a double cardan.

 

[Fouledplugs]

Beat me to it, I’ve been procrastinating. I asked what the importance was behind axle centering in another thread a week ago or so. A user had installed a reasonable amount of lift (2 inches, IIRC) and the front axle had shifted to one side. I believe his rear axle did the same thing. We all know it happens when adding lift.

The user was asking if it mattered whether or not his axle was centered and should he get an adjustable track bar. I advocated for getting the axles re-centered under the Jeep to replicate factory suspension setup.

I took a few punches in the thread and was told it didn't make any difference in drivability. But no one could tell me why it didnt matter. Or at what point is does start to matter.

I began to wonder, why did the Jeep engineers center the axles? Why did they think it was so important to center the axles? Why does 1/2 - 2 inches not matter but more does? Where is the line in which it begins to matter?

What is the difference in offset of the 8.8 pinion when compared to the Dana 35? Because some folks believe it kills the deal for a swap based on it’s offset..does that not correlate?

I’m not trolling, I would love to know the answers to those questions, as I have no idea.

 

[Fouledplugs]

But at 2" of lift it shouldn't be an issue whatsoever. The axles will be off center laterally, but likely no more than 1/2" give or take

What is this based off of? And if that is known, at what point does it become an issue that deserves attention?

 

[Fouledplugs]

https://wranglertjforum.com/threads/front-track-bar-not-aligned-with-2-lift.43617/

 

[Blackjack]

Beat me to it, I’ve been procrastinating. I asked what the importance was behind axle centering in another thread a week ago or so. A user had installed a reasonable amount of lift (2 inches, IIRC) and the front axle had shifted to one side. I believe his rear axle did the same thing. We all know it happens when adding lift.

The user was asking if it mattered whether or not his axle was centered and should he get an adjustable track bar. I advocated for getting the axles re-centered under the Jeep to replicate factory suspension setup.

I took a few punches in the thread and was told it didn't make any difference in drivability. But no one could tell me why it didnt matter. Or at what point is does start to matter.

I began to wonder, why did the Jeep engineers center the axles? Why did they think it was so important to center the axles? Why does 1/2 - 2 inches not matter but more does? Where is the line in which it begins to matter?

What is the difference in offset of the 8.8 pinion when compared to the Dana 35? Because some folks believe it kills the deal for a swap based on it’s offset..does that not correlate?

I’m not trolling, I would love to know the answers to those questions, as I have no idea.

IIRC the offset is 2.5 inches. The irony is that it is only a problem when it becomes a problem. Part of the issue with 8.8s in TJs is the short rear driveshaft. Putting an 8.8 in an XJ is no biggie as there is plenty of shaft length to make the offset easy to adjust for especially with a double cardan. It all matters, lift height, raised belly, gear ratio, tire size all play a role in if you will have issues with any setup 8.8 or not. The 8.8 just adds an additional complexity to deal with.