What causes "wander" in an Ex?

Is it mostly the front springs?

Do the rears need to be changed or modded? And which of those two options is best?

Not looking to make the EX a "taller" truck, as it is my wife's, but she said it seems to want to move in lane a bit... two hands on the wheel

 

It's both.

While no two Excursions are the same with regards to how much the fronts are the cause and how much the rears are the cause, the cause is due to both front and rear springs.

The rear springs are weak and will easily allow axle wrap. That's why hard braking, hard acceleration, or driving over uneven surfaces can make you feel the wander.

That's also why the RAS helps with the wander, it reduces axle wrap.

The fronts are weak and will deflect from side loading of the spring, which can be caused by the rear axle wrap among other things. That's why lane changes can make a driver really feel the wander. The side loading from the lane change will cause the fronts to react and give that extra shimmy, wiggling the rear of the Ex.

Stewart

 

Thanks, that's interesting...

I have read all the threads on wandering and can safely assume with 80k mi on our 05, the springs should be replaced.

However, I also read where some have swapped the factory rear 26mm bar to an SD 30mm bar, curing (masking??) wandering

 

On ours we found that the back has to be slightly higher than the front. if not it wonders like crazy. We added new heavier front spings and higher tappered blocks in the bag with air bags. The air bags are primarily for towing our camper. Like others have said it seems no two EX's are the same when it comes to solving this issue.

 

I can't say if both are required (I have to trust more experienced guys like Stewart and the dozens of others that have figured out how to cure their particular wander), but I would imagine that unless you want the 'pre-runner' rake (where the front is taller than the rear), you almost have to do something to both the front and the rear.

You said you had 80k+ on the odo...I had 93k and already had significant sag on the front springs. I rode almost level, with just a touch of height on the rear (maybe 1/2" or so)...fixing the front would have given me a "front up" rake, so I had to do either blocks, RAS, or different springs on the rear.

I think we can all agree (using Stewart's comments above) that you have to do the front, so count on doing something to the rear if you want to keep a level or rear-up rake...if you tow, you may want to ensure you have a rear-up rake.

I'm assuming you have seen some of my comments as to why I went with springs instead of just blocks - if I was going to raise the rear, I wanted height and strength, not just height.

I have to say with V/Modded B's, the truck rides fantastic. I have the stock front sway bar and after replacing the sway bar links, the roll is very stable. I spoke to some others that added a rear sway bar and they said the roll gets very stiff with both...if you do a lot of city driving where you turn in to parking lots or drives where you have a good angle change, you may find yourself being thrown around the cabin a bit since the roll is so much stiffer.

 

Before getting springs, you can try adjusting the steering box (instructions in the wander thread) quite cheaply to see if there is any less wander. Worked great when I still had the original springs.