Ball joints VS Hiem Joints

Im going to do my saggie swap and in my current plans Im going to use Hiem Joints instead of Ball joints. Do yall see any problem with the setup? We use Hiem joints in all of are races cars and they hold up very well on dirt or asphalt. Most cases they are stronger then the tie rod they ar attached to R)

 

Jason, I'm planning on heim joints when I do my drag link conversion. The author of the article in the tech section said that dirt/rust wasn't an issue in this thread.

 

Well On dirt cars alot of guys have poly disk covers that cover them. I dont know if some one makes them or its a home grown thing. Im thinking you can buy them though because of Ive saw them on differt cars in color to match.

 

have seen greasable hiems. not cheap thou.

 

Jason, keep me posted if you find the covers. Wouldn't mind having
a set.

 

Hi all, I have a lot of experience with spherical rod ends (heims). The heims hold up pretty well if you get the 3 piece rod ends with the teflon liner. The liner acts as lubricant to the bearings motion, but it also acts as a wiper to help keep the rod end free of dirt, sort of like how disc brake caliper pads wipe a rotor clean. The two piece rod ends have too much play between the ball and body and dirt easily works it's way in and can wear or destroy the joint.

Also, when shopping for heims, do yourself and others on the road and trail a favor and skip the cheap ones. Economy rod ends break more than the good rod ends. I know a famous rock crawling champ who learned his lesson the hard way when a cheap rod end let go on the freeway, luckily his well recognizable bronco stopped nice and straight, and he survived along with those around him... although his shorts didn't! Go for the Chromoly, 3 piece heims, Speedway racing and hotrods have very good prices on them. If you still want to seal the heim up better, a company called Seals-It makes sealing washers that can keep the junk out of the heims. I have had good luck with the 3 piece heims for the last few years now.

Lastly, but more importantly!! If you can not properly design a double shear mount for a heim joint, do not use them, and stick to factory style joints instead. Heim joints mounted in a single shear are just plain stupid. And yes...I know a lot of people do it, and there are even companies that sell kits to do it, but from an engineering and safety standpoint it is WRONG. The ONLY correct way to mount a heim joint is to create a properly engineered double shear mounting point, and to use a correct bolt with the proper shoulder length so that the threads of the bolt do not lie within the the confines of the double shear arrangement. The military and race car builders use special shear bolts, designed specifically for this pupose. Although they are not cheap, they are the safest way to secure a heim joint in double shear. The shear bolts I purchased for the four-link on the back of our CJ cast me about $9 EACH! Rediculously high priced?...Yes!...but I did it to keep my rig safe for myself and for anyone else around me. Let's all remember that making modifications requires us to be responsible!

I have tried heims in the steering linkage too, and after years of experimentation, I currently run factory style tie rod ends. They are well designed, easy to maintain and replace, and larger versions are available in an infinite number of configurations to suit anyone's need. The factory style ends I prefer are common on GM trucks and fullsize jeep trucks. Parts Mike puts together some great tie rod and tie rod end kits using these larger factory tie rod ends. They have lasted me through some of the most difficult trails in the country, and they even survived my wife in the Women's Rockcrawling Championships in New Mexico.

Bottom line...my recommendation would be, if you do not have the time or resources to design a proper double shear mount for a heim joint, stick with factory style tie rod ends.

 

Thanks for the write up UglyJeep. (you need to get a sig attached to your profile so we know your first name!)

Could you elaborate on your concern for the Heim joints in single shear as they might be on an older Jeep? It seems that there wouldn't be any more force exerted than a standard TRE, so wouldn't a sufficient Heim joint be acceptable in that case? (I'm not doubting your concern, rather would like to further understand the mechanics behind it. Any education would be appreciated! )

The advice is much appreciated, thanks!

 

The forces are the same, but I think its the way the forces are handled that become different. The regular ball joints are designed to work in single shear and thats one of the reasons that tie rod holes are usually tapered. The taper allows a good solid fit that can't move around. Whereas with heims you have to use some kind of bolt to hold it all together and at that point it becomes the tension on the bolt that holds it all together. That tension is also the only thing keeping the bolt from bending. Its hard to explain, but if they could just drill holes in steering arms and not have to taper them then why wouldn't they. Obviously theres a reason.

Having said that I've seen both setups on some hard trails and they both seem to do just as good as the other.

Kevo

 

I Have a double shear mount drawn out.Ive never saw the Three piece heim joints , Ill defently check into them. My plan was to do a high steer with the drag link stacked on top of the tierod to make my bump steer none exsitant.

 

I will say Jasons bar napkin drawing of the double sheer setup looks to be very good. Now we got to see it in real life though R)

 

Hi, heims in a single shear are not the same as a factory tierod end for one simple reason...the bolt! Bolts are not designed to be a trunnion of a joint, bolts are designed to clamp and not to be subjected to the physical forces which act upon it when it is used as a trunnion. A visual example would be to imaging bending a coat hanger repeatably in the same spot, eventually you know that wire hanger is going to break in the spot where you are applying the load. That spot is also present on a bolt that is loaded in a single shear, it lies at the interface between sperical bearing ball of the heim joint and the knuckle that you have it bolted through.

When I speak of a single shear, I mean that the heim is simply bolted on top of an structural member. The only thing that resists the forces that are placed on a joint in this single shear is the bolts ability to absorb shear forces by using the tension forces applied by the bolt being kept tight. Hole tolerance becomes a key issue in stregth in a single shear joint. By nature, all holes that a bolt go through have to be larger than the outside diameter of the bolt. It's this difference that creates some amount of slop and allows the bolt some room for movement on a microscopic level as shear load, or side load, is applied to it. This principle is why you find tapered shanks on factory tie rod ends that mount in single shear. It is still a single shear joint, but the tapered fit helps to lessen movement and fatigue that can be caused by a the improper fit of the bolt in a drilled hole.

There are some bolts that are an exception to the rule, and can be used as a trunnion in a double shear application. These are the special bolts designed by the aviation and aerospace industry, called shear bolts. Shear bolts have many variations, but they share some common features; they have special hardness and fatigue properties that make them better suited for use in shear applications, they have outside diameters that are larger than conventional bolts so they fit with very close tolerances in properly sized holes, and they are available with shoulders (the unthreaded part of the bolt shank) that are sized in small increments of length, so that one can choose a bolt with a shoulder length that allows you to not have threaded portions of the bolt within the structural members of the joint.

A double shear joint has the bolt properly supported by a structural member on both sides of the heim joint. In addition, the load must not be allowed to directly rotate on the bolt for obvious reasons. A correctly designed double shear joint has the supporting members of proper strength and size, proper hole dimensions and alignment, and a bolt that possesses the an ultimate strength and fatigue life that will exceed the physical demands placed upon it in a joint.

In theory, if a bolted joint is designed and sized properly for a given application, the greatest stress that the bolt will ever see is when it is torqued to proper specifications. When a bolt is tightened to it's recommended torque spec., it is subjected similtaneously to tension and torsional stresses sufficient enough to stretch the bolt to it's proper clamping force.

A good design practice to follow when building a double shear joint is to remember to keep the smallest material thickness of the structural member about 1/3 of the thickness of the bolts diameter. For example, if the joint requires 3/4" heim joints, the material used should have a minimum thickness of 1/4" on each size of that bolt. Steering arms will certainly have one part of the structural member that is thick, (since it is a steering arm), but your supporting lug to make it a double shear should be approximately 1/3 the thickness of the bolt diameter. This rule is pretty sound practice if you are using 1018 cold roll steel plate to fabricate with for use on our jeeps, where we generally build things stronger than the average fabricator would if we were building a car. Those using chromoly can get by with even less thickness of steel, because it has a greater bearing strength than mild steel. Conversly, those using hot rolled steel for building structural members should use a little thicker steel, or even better, switch to the stronger cold worked steel plate, it is not that much more expensive, and it is stronger than hot rolled steel and it doesn't have that annoying scale on it that has to come off for welding.

For those of you not put to sleep by my dribble ...I recommend you check out a book by Carroll Smith, called the Nuts, Bolts and Fasteners Handbook. It is an excellent read for anyone interested in fabrication and engineering. Consider it homework for those willing to take responsible steps towards safety when they are designing and building cool stuff for their jeeps. Billa Vista of the Pirates of the Rubicon board has a ton of info on this on the Pirate site, including excerpts and diagrams from a couple of Carroll's books. His other book, Engineer to Win is another excellent must read for those of us who like to learn, like me. These books are geared toward the serious race car builders, but the info in them is valuable to any of us with the will to create.

Thanks all,
Daniel

 

Nuts, Bolts, & Fastners is a good book. It will make you think twice about the hardware you use in your rig. Good education. Recommneded reading.

 

Good info Thanks

 

Just ordered that and "Engineer to win" for $36 including S&H. Link below.

http://www.amazon.com/gp/product/0879384069/102-9425418-2744119?n=283155

Thanks for the info and heads up!

 

thanks for the info.........