sv41878

Ah see, I put in a steering box brace on every Jeep cuz they are known to be sh##. I also do steering upgrades in every Jeep I have ever owned, but that is a personal preference and I wasn't gonna tell Shepwood he should do that. A drop pitman arm will not hurt a Jeeps performance, well maybe if you put it in one that wasn't lifted but not even sure then.

I've seen every kind of lift done, seen and probably taken most of the short cuts your just learning. I have about 25k in tools in my garage just for lifted trucks, that's not including the regular stuff I use to fix cars/trucks everyday. I've never had a vehicle I lifted fail from any reason other than driver malfunction. And still I will admit I don't know everything. I would personally add a drop pitman arm on a 4.5 inch lift, don't care who doesn't. It's a choice and I think it makes the Jeep handle better.

As for getting stuck, 1 or 2 times a trip. Do you not know how to drive? I've been stuck once in the last 2 years and that's cuz I knew I shouldn't try it and did anyway. Took 3 other Jeeps to pull me out cuz the mud was coming over the hood. Routinely I go into mud above bumper level and crawl through it cuz I made sure my Jeep had everything it needed to handle as sweet as possible.

Where do you live, can I talk you into coming to play with the big dawgs during the spring thaw? Not sure it's a good idea cuz if you come at the Jeeper's I roll with and have that cocky attitude, you might get a shovel and told to dig yourself out when you get stuck, and you will cuz where we go isn't amateur hour. But I think it would be fun to teach you a lesson about what happens when you don't build your Jeep right. In real mud, you would learn a little lesson about what I'm saying about the angle being too much when you don't add a dpa by snapping off the tie rod end on the pitman side when you crank too hard on those wheels that wanna stay straight.

Don't take offense to what I'm saying, I've met too many punks your age who think they know everything cuz they have built 6 jeeps or lifted a couple of trucks, but then show me they don't know their *** from a hole in the ground when I let them loose in my shop. Got one kid who is using space once a week cuz he won't listen, he's learning, but it's a process.l he will still tell me everytime I see him that he knows everything.

You may or may not be one of those punks, the fact that your gonna argue instead of agreeing that a dpa is a personal preference tells me your a punk who doesn't listen and thinks he know everything cuz he's fixed a few cars or lifted a few Jeeps, but I can be wrong. If I am, I'm sorry. But cocky gets you nowhere in life except looked upon as a fool.

Either way, I'm bigger than that and Shepwood go to the RC site, I saw a good 4.5 kit that I think includes about everything you need to lift. I think they called it the stage 2. Upgrade so you get the new rear springs, stock springs are notorious for flattening. From there, it will be more about feel anyway. No 2 Jeeps behave the same.

JeepCoMJ

*shrug* I agree to disagree with almost everything you've said about me, personally (almost...I know I'm cocky, however, I know I'm not stupid and I KNOW that I don't take shortcuts).

I never argued whether DPA was a personal preference...just whether it was correct or not. I'll stand by my guns and the fact that my jeep has ZERO bump-steer at 6.5" with stock steering and 35" tires. check out my build thread if you want to critique my building style (but go ahead and critique my indecisiveness lol)...but do some research before you do critique a specific person about their rig. I don't know the specs on your rig and so I haven't critiqued it...solely have been arguing about your *opinion* that DPA's are necessary, and I've been arguing using geometry as my basis.

I'm from WI so wheelin w/ you isn't gonna happen any time soon.

89eliminator

man, i must be a REALLY big punk if im only 20

sv41878

But the only thing you've said involving geometry is that everything must remain parallel, which is true and where the dpa comes into play. If you push everything down 4.5 inches, but the pitman arm remains in it's original position, then the steering rod connected to it is no longer parallel as it should be (and your tie rod on that end is torqued harder than it should be).

Yeah by the way your one of the punks cuz you won't accept I might be right at all, you have to be right. The excuse that your in WI is nothing, any pro trails around there, I am going to WA this spring and would be willing to stop along the way and teach you a lesson on those instead.

Specs on my ride, which one? Wanna talk about the 46 *****'s, the 94 with the 6.5 inch lift or my 96 DD with the 3 inch lift?

Out of curiosity, do you use spacers for lift in the from and blocks for the rear?

sv41878

No being a punk has nothing to do with age, it's all about attitude.

sv41878

Not a bad Commanche on the build thread, should bne proud of it, but I'd like to see more suspension picks, the few there are quite blurry. The bumpers are sweet, what would you charge for a set shipped?

JeepCoMJ

again, that's not true. when you lift a vehicle (take a DPA out of consideration), the upper and lower mounting points for the track bar and drag link remain in the same locations (yes, the drag-link changes minorly because it becomes out of alignment and you need to re-align the vehicle), provided you use an adjustable track bar instead of a track bar drop bracket.

the only thing that changes (geometrically) is the distance between the track bar and drag-link points A (body side) and points B (axle side).

With that in mind, seeing as the track bar and drag link are parallel to each other from factory, they remain parallel (figuratively...the bars are not parallel due to shape/design to allow them to fit, but the points between A and B are parallel to each other when the axle is properly centered) after the lift.

the only other thing that changes is the angle of operation of the tie rod ends on the drag links...it becomes less ideal the higher you go, which is where an OTK steering kit, and/or a combination of DPA and track bar mount drop come into play.


your 94 sounds the most interesting. I don't much care for old *****'s unless they're a pickup like 89elim's dad's, and a 3" D/D xj is not likely to be impressive to me.

oh, and don't be silly. you can't use blocks to lift an MJ...they lower it. gotta love factory SUA.

my wheeling truck is an 87 MJ swb, 4.0 H.O. conversion to a 95 (I built the trans and t-case and modded the factory reman motor...tho I've built several 4.0's). it runs a set of 6.5" RC coils up front, with RC 6.5" adj. control arms...tho I now have all of the currie flex joints and rubber bushings/collars to build the longarms once I design them.
aw4 trans
np231 t-case with a proper SYE (was not necessary due to the wheel base, but is convenient for the sealed output)
double cardan (which is NOT a CV) rear driveshaft
RE HD track bar and mount (superflex uper bushing)
steering box brace
edelbrock extreme IAC remote reservoir shocks all around
welded disconnect dana 30 front, 4.10 gears. disconnect is air actuated via a manual switch
SOA rear, 2" perches, pinion angle set accordingly (2 degrees below in-line with the driveshaft to allow for torsion in forward gear)
dana 44 rear, currently open will most likely get a detroit and going ARB in the front when i convert them to 4.88's
RC swaybar disconnects
YJ front brake hoses
dodge dakota rear brake hose
cragar soft 8's with 35x12.50r15 daytona mud terrains
on board air (york compressor) that I have to finish the mounting brackets on
custom front and rear bumpers, full skid plates, chopped wheel wells, and I need to install the teraflex boomerangs.


it's hardly the piece of crap you expect it to be, no?

JeepCoMJ

thanks. I'm not in the market to sell any bumpers at the moment. pending how my brother (19 y.o. professional welder @ bucyrus) decides to do things, he may open his own line of bumpers and other jeep goodies in the next few years. I'll get you more suspension pics when I do the longarms.

sv41878

OK I know it's a TJ used in the explanation, but it's the same as a cherokee, coil spring suspension and shows in colored diagrams exactly what I have been saying about a track bar relocation and dpa being needed when lifting 4.5 or higher.





Bump Steer Explained



If you have ever driven a lifted Jeep one thing you notice is the steering. If special care is not taken in the design the vehicle will dodge and dart whenever a bump or hole in the road is hit. This is because the drag link is either being pushed or pulled by the vertical suspension movement due to not being parallel with the trac-bar. This is commonly referred to as Bump Steer.
Lets examine the components of a typical steering set-up. The axle is supported in place by the control arms and a trac-bar on a TJ suspension. Consider the leaf springs to be the control arms in an YJ/CJ. The drag link is connected to the pitman arm and also the tire rod. The drag link is pushed or pulled by the pitman arm and in turn pulls or pushes the tie rod turning the tires of the vehicle.
The diagram below shows the parts of a Jeep TJ steering and suspension.


When bump-steer occurs the suspension moves in a vertical plane and the drag link is trying to be lengthened or shortened by this movement. Since its length cannot be changed then the only way to shorten or lengthen it is to turn the wheels. Shortening it would move the wheels to the Drivers side, and lengthening would move it to the Passenger side. This is generally due to the trac-bar not allowing the axle to move side to side. Often in leaf sprung vehicles the trac-bar is removed to help hide the effects of bumper steer since it then allows the axle to move side to side. This however, creates tracking issues on the highway and sometimes this can be more dangerous than bump-steer.
Generally speaking, once a TJ is lifted the drag link and the trac-bar are no longer parallel to each other. Keeping them parallel is the key as this makes them close to being in the same plane of movement and thus they mimic being the same length through the general arcs of movement. Imagine the pitman arm and the top trac-bar mounts being the start points of an arc and they both have to keep as close to each other and in the same plane as possible. Extreme flex on the trail though may not allow this to hold true as your moving so slow on the trail you may not be notice the bump steer. [IMG]file:///C:/DOCUME%7E1/JAMESB/LOCALS%7E1/Temp/moz-screenshot-5.jpg[/IMG]
In the drawing below we see the arcs of movement created from an unparallel trac-bar and drag-link.




Notice the very narrow range that the two arcs are parallel with each other. This is the only point where the drag link and the trac-bar are the same length resulting in limited to no bump steer. The further the suspension cycles on the vertical the greater the bump steer due to the differences in the arcs.

In the drawing below we see the arcs of movment created from a nearly parallel trac-bar and drag link.


With the drag link and trac-bar being nearly parallel the arcs of movement have a broader range of continuity and thus a greater range of movement with no or limited bump steer. The drawing does show them nearly horizontal which rarely happens on vehicles but for example purposes it is the best way to represent the set-up.

Lift kits generally come with a trac-bar relocation bracket and some even suggests a dropped Pitman arm.


The drawing to the left illustrates a trac-bar and drag link set-up on a lifted vehicle. Notice the very uneven angles between the two creating severe bump steer.








The drawing to the right illustrates the same set-up but with a trac-bar relocation bracket and a dropped Pitman arm. The two bars are now closer to being parallel than they were before.








There is no guarantee that this will cure the bump steer, as the suspension settling and the weight of passengers and cargo will alter the geometry on the highway. It will however limit the bump steer to the point of being safe to drive and not being driven into the opposing lane with every bump on the road.

With no two vehicles being alike what may work on one Jeep may not work as well on another. Please follow the instructions of the lift manufacturer and requirements for installation.

JeepCoMJ

already read that article, and it just adds to how sure I am of myself.

sv41878

Nah sounds nice, good set up. How are those Daytona's on the road, was looking at a set for my DD when the snow hits. I think the last post says it all, shows the geometry in detail, can we play nice now?

sv41878

How do you figure, it shows how you MUST keep the drag link and trac bar aligned, which you can't do without a trac bar relocation and dpa. Shows why in the diagrams.

sv41878

My old *****'s is nice, only about 900 of them made (special order civilian model) and still has all the original metal. Books at like 40k. Priceless to me.

JeepCoMJ

yup. my main point was simply that a DPA and track bar drop must be done at the same time...you cannot do one or the other.


anyways, no idea how the m't's handle. my bro got them for a song, I bought them off of him and have about 300 miles on them. d/d duties I run 33x10.50 bfg a/t's on ar767 rims (15x7)...though I really do want a set of 35x12.50 bfg a/t's for it. my a/t's are pretty much as bald as it gets right now.

and the truck is an ongoing project. that's a good piece of advice actually...you're never gonna be done.

sv41878

And I told him in the beginning that he needed to do a track bar relocation (I think it came in the lift he was looking at) and thats where the dpa came in. Are we both right?