juice

Does anyone know how high you can lift a Ram 2500 before driveline adjustments are necessary. The reason I ask is because I thought that since no one has an 8" lift for the 3 gens, I could order new coils and leafs to raise my truck another 2" for a total of 8".

TXboy

not to sure, i was talkin to my uncle about a lift and he said on almost every truck after 5 or 6in you need to at least tilt the axle for less stress on the u-join of the drive shaft, but that shouldnt be to hard. ill see if i can find out anything else.

TXboy

one other thing that just popped in my head is a body lift, u could go two inches on that and it prolly wouldnt look too bad, and that would be really cheap, if you did it yourself polly $100 to $150. You could also add jus a 2 in leaf block in the back which would be cheaper than brand new leaf springs and then still go with the new coils up front, not sure how much the leaf bolcks would cost. Another thing is im sure with a 6in lift you could throw 37in tires on that badboy. That would be some more ground clearance, make it taller, and prolly even look a little cleaner.

If you dont want to add more stress on the driveline go with a body lift or bigger tires.

djgaston

There is a reason you don't see 8 inch lifts for these type of trucks. The front driveshaft spins all of the time and if you go past 6 inches, you are definitely going to get vibrations from hell. You have a couple of choices.

Remove the front driveshaft.

Install a manual locking hub conversion.

Index your transfer case down one notch.

Up front, "tilting the axle" is not only stupid, but not necessary. When you lift the rear, of course, you use shims to angle the yoke up towards the transfer case output slightly. At 8 inches of suspension lift, you only need to do that about 3 degrees. The only time you see somebody rotate the front pumpkin is on incredibly huge, gay show trucks with over 20 inches of lift minimum.

Body lifts are not recommended for diesels. In fact, you can't even install one without some modification to the intercooler tubes.

Even worse than a body lift on a diesel are rear axle lift blocks.

PanteraGSTK

These guys make a 5.5" lift and two different coilover 8" lifts for 95 to present Ram 2500's

Oh yea, forgot about kelderman

cquestad

djgaston,

I have pushed more than 500...now closer to 600 hp through 3" rear axle blocks for over 50,000 miles (80,000 miles total on the lift now) and have not had any of the ill effects (in somecases...old wive's tales) you may be suggesting. Zero vibration, axle hop, axle wrap, spring damage, ujoint damage (have not replaced one piece of the original driveline), or breakage of any kind. Maybe we should break this down a little....

There is a large moment created in the rear axle/leaf spring assemble by the rotational force (twisting) of the tire propelling the vehicle. We will call this the primary moment. It is large....500 ft lbs or more (much more for some ). The distance the center of the axle is away from the centerline of the leaf spring mounting eyes does not effect THIS moment. Not at all!

However...there is a secondary moment that is affected by that distance...as well as tire size, etc. The maximum that moment could be would be the traction threshold of the tires (lbs force) multiplied by the distance that force is applied away from the centerline of the leaf spring mounting eyes. Remember...this distance does not know whether a spring or a block is there!

Lets use my truck for an example...

Primary Moment = 1050 ft-lbs (from last load dyno)

Lets assume that my rear tires may see up to a 3,000 lb downward force with weight shifting etc....heck...lets make it 4,000 lbs incase something is in the bed!

The maximum traction threshold would be based on contact patch as well. 4,000 lbs / (45 psi x 2 tires) = 44.4 sq. inches. That sounds about right...2 contact patches of 11" wide by 2"...so we are on the right track!


Secondary Moment = (4,000 lbs x .6 friction coefficent) x (37"/2 +3" block)/12 = 4300 ft-lbs. Wow...it is even bigger!

Secondary Moment on stock drivetrain = (4,000 lbs x .6) X (32"/2)/12 = 3200 ft-lbs

Primary Moment = 500 ft-lbs (stock dyno)

Comparing the two trucks....

My total Moment = 4300 + 1050 = 5350 ft-lbs
Stock Total Moment = 3200 + 500 = 3700 ft-lbs

So...tires and lift and engine mods increased the total "twist" by 44%!

The leaf spring pack can resist this moment to prevent axle wrap/hopping, breaking, etc in two ways. If the spring pack is very flat (not much curvature), the mode of resistance would be the resistance to bending. If the spring pack has a lot of curvature, the mode of reistance shifts from pure bending towards a combination of bending, compression, and tension.

It is a fact that the spring with more curvature will resist twisting more the flat spring and the same relative spring "load carrying" rate. It is also a fact that that same curved spring will be much harsher and not flex as much due to the same properties that allow it to resisting twisting!

So the real question is...do you settle for a worse ride in FEAR of axle wrap OR do you enjoy a plusher ride and possibly risk some negative related to axle wrap? I choose the later...and don't regret it. 80,000 miles of hard use later...don't regret it!

The best solution is properly designed "ladder" bars that swing with the natural axle travel, don't hamper side to side flex by using helm joints/ bushings, etc, and most effictively RESIST twisting in combination
with "flat" plush springs! This allows the spring to do best what they were designed for...provide cushion...not resist twist.

I will build "ladders" if I can prove they are ever needed to begin with...by breaking something?

Lose anyone?

marc03

blocks are fine as long as kept 4" or less. And the trucks leaf springs are well designed and are in good shape.

Crimedog

cquestad - Now you obviously seem to know your stuff, however I think you are forgetting about one important aspect, the increased radius between the spring and the axle. This means that with the same amount of force, you are getting more torque on the leaf pack because of the increased distance... T=FxD This is the reason that a tall lift block is going to give you more spring wrap, because the axle has more leverage on the springs.

cquestad

I kinda covered that with the portion of my post...

The "global" moment is the same...because that distance is measure from a straightline between the supports. The local moment...would be measured from the spring. That explains why the spring with more arch resists the twist better. Less local moment....but same global moment which is resisted by force vectors more "inline" with the spring...hence the tension and compressive forces mentioned.

The whole point of the post is really ride quality and durability. One spring provides a nicer ride quality and cost savings and the reduction of durability is questionable. I am just questioning the purpose of overthinking this...and looking at track records/miles down the road to reinforce the "simple and effective" varity of mild rear lift.

A very softly leaf sprung rear of a high horsepower jeep or something...WOULD have very big issues with axle wrap. A truck with a large built in payload in the spring design has minimal worries!

Those who are seeking the "ultimate" offroad system in the rear should be looking at 4 link coil sprung anyway!

CrashCade

This stuff is all elementeray. If you keep your pinion angles pretty good and make sure you have nobinding on the front. You are good. I have benn pushing 600+hp and 1300+ trq on 37"s with a 5" block with no wrap problems, no binding.... Just use a good adjustable front four link set up so you can keep Caster in check and evrythign will be great. It seems like people are afraid of trying new stuff that has been around for years, but because they are using a newer truck they are scred to make that jump. I say grab those cajones and go for it, especially if that is the look you are wanting.

You do not need to do a cut and twist on these trucks unless you are going into the 16=" range.... Justy my .02 and definitely not my first true off roaders!

TXboy

Even worse than a body lift on a diesel are rear axle lift blocks. [/QUOTE]


Im just throwing out sugjestions, but could u explain why lify blocks are such a problem???

not much different than new leaf springs... and alot better than a body lift.

And thats the differnce in lifting a 2500 diesel or a 2500 gas, the lift kits will be the same!

cquestad

TX,

Try reading my post again...it does have an effect. I am sure he implied diesel becuase of the insane torque we all have.

The effect is neglible IMHO.

juice

Holly Information!! That is more information and equations than I expected....but thats great that I caught the attention of people who know what they are doing.

CashCade, I noticed that you have a leveling kit on top of you 6" lift. Does that mean that you have an 8" lift in the front and just a 6" in the rear? Also, does your 6" lift consist of a 6" spacer in the front or a new coil? I am really eager to lift my truck just a little more so that it doesn't look like everybody else's off the dealers lot lifted dodge. I kind of figured that ladder bars might be an issue I would have to deal with if I chose to go this route. Thanks again for the info.

rockittboy

i built a 10" lift w/some tips from dj...worked out pretty well, front driveline is out pending it being lengthened and an indexing ring procured...check my gallery

juice

Did you have to do anything to your rear driveline? Your truck is huge, maybe a little larger than I am looking for but it still looks sweet.