The Stovebolt Site Forums The Shop Area Driveline Using Heim/Uni-ball ends for Drag Link

I haven't been happy with my homemade tie-rod end drag link and thinking about using hiem/uni-ball ends. Has anyone done this or thought about it?

They are not designed to be lubed, they are a short term item, use standard tie rod ends.

Ed

They have several drawbacks when used that way. Several of the guys I used to race with tried it- - - -most of them ended up in the wall at the end of the straightaway after one or more of them failed unexpectedly.
Jerry

Ouch and double ouch. Appreciate the feedback.

Chad,

The SCTA (Southern California Timing Association) sponsors Bonneville Speed Week where cars run 200 MPH, 300 MPH and even 400+ MPH and has very extensive and conservative safety rules and inspections to enforce the rules. I've been there and seen the inspectors check every detail, no matter how small.

Here's what the SCTA rules say about spherical rod ends in suspension and steering applications:

http://www.landracing.com/forum/index.php/topic,2688.0.html

In salt flats speed trials details matter not only for safety reasons but also because records are often raised by fractions of one MPH, it's that competitive.

Bonneville salt flats speed trials should be on every motor head's bucket list. Seeing those kinds of speeds is like nothing else on earth. Some truly amazing vehicles show up. An example is the Poteet and Main flathead Ford powered streamliner that set a record of over 300 MPH with true flathead power (one engine, no overhead valve conversion). Doing that required that the flathead deliver about 700 HP (without exploding) according to calculations I've seen. Doing that successfully sperates the talkers from the doers.

I'd stay away from them as already mentioned for critical steering and suspension joints.

They do make some you can grease, but they're still in my mind not as robust or safe as factory type tie rod or drag link ends.

"I'd stay away from them as already mentioned for critical steering and suspension joints."

Good morning Grigg.

If I'm not mistaken they originated in aircraft applications and based on that the quality ones must be pretty robust as long as they are sized correctly for the application. The Speedway Motors catalog lists a variety of spherical rod ends. It's hard to imagine how there could be a problem if the SCTA required washers are used. If they're adequate for a 400+ MPH streamliner they must be pretty solid.

One of my sons is a mechanical engineer and he works in a test lab called Tension Member Testing. They test some really massive stuff there, stressing it to failure with fixtures that can apply in excess of a million pounds pounds of tension or compression. If anyone's interested I can ask him if they've tested spherical rod ends. The manufacturers of those parts have test data also that would give people a comfort level. Here's an example:

http://www.rbcbearings.com/literature/pdfs/rbc-heim-
092109.pdf

Their offerings vary from miniature up to 1" shaft, with and without grease fittings.

But there are other options. When I restored my '36 PU it had clunky, loose, spring loaded tie rod ends on the tie rod and drag link. Digging through a Moog suspension parts catalog back in the 1970s turned up ES29R and ES29L tie rod ends that had the same internal threads and the same taper as the original parts without the complexity and looseness. Using them on the drag link did require getting a round bar and threading the ends with left and right hand threads for ease of length adjustment. That was a quick and easy lathe project. Those Moog tie rod ends are still tight today.

Chad may find an equally adaptable part for his application by doing some research. It's amazing what's out there.

Consider your hands spanked by the Google guru, Grigg! How dare you question the search-meister?

Where's that "sarcasm" emoticon?
Jerry

Yar, I agree with your suggestion to look in the Moog catalog and find a suitable interchange for a modern tie rod end, and to make or find the threaded rod or tube to suit.

Your other points about spherical rod ends are true I expect...
What you have not mentioned is a land speed car and most any race car or off road buggy is not designed or expected to last for 10's and hundreds of thousands of miles.

Ultimate strength is only one of the considerations for suitability of a part for a given application.

Uni-ball ends are used on 3-point hitches on tractors. They are huge and heavily greased. In no time at all, they become as loose as sauce squirting out of a sick cat recently throwed under a door to gauge the size of the draft. (I prefer my metaphors heavily mixed.)
Carl

"Yar, I agree with your suggestion to look in the Moog catalog and find a suitable interchange for a modern tie rod end, and to make or find the threaded rod or tube to suit."

Hi Grigg.

When I restored my '36 PU I was very pleasantly surprised to find out how many parts there are that fit other applications than what they were designed for. On my '36 a couple of quick examples are the Moog tie rod ends and Porche 356 passenger and driver's side door window rubber seals that were both a perfect fit. Back in the early 1970s the local Porsche dealer had the window seals in stock.

I owe this type of search to a neighbor I had as a teenager. He had an engine shop and in addition to modern engines of the day he also took in antique car engines. I used to visit his shop just to see what was going on. On one occasion he was rebuilding a Ford Model A engine. He very enthusiastically showed me that he had found a then current Oldsmobile piston that was perfect for Model A use. Because of that kind of creativity he was able to turn out antique vehicle engines at a fraction of what the antique engine specialists were charging for the same thing using expensive aftermarket antique parts.

Another example is from my off road motorcycle racing days. I had a 250cc 1977 Suzuki that was wearing out pistons very fast and that was getting expensive. It turned out that 250cc Maico race bikes had much higher quality Mahle forged pistons that were a direct interchange. Even the pins that locate the ring end gaps to keep the rings from catching in the ports were correctly located. Again, it's amazing what's out there. All we have to do is a little catalog reading or online research.

As to the durability of spherical rod ends I have a 1952 Ford 8N tractor. Its 3-point hitch mounts both my 5 foot mower and an 8 foot wide angle blade using spherical rod ends and they are holding up very well. The quality of the rod ends probably affects longevity.

Then by all means put them where ever you can on your vehicles. Just stay on the West Coast. My family lives on the East Coast, and I try to keep them alive and well.

The Four Wheeler Network forum has a posting on this subject:

http://www.fourwheeler.com/how-to/131-1306-steering-you-straight-heim-joints-vs-tie-rod-ends/

Those 4 wheeling guys really abuse their equipment. The posting has a lot of details and photos and includes information on really beefy parts like the ones that would be used on a heavy duty truck and its bottom line comparing factory tie rod ends and spherical joints is:

"Our research concluded that if you want to do the least amount of maintenance, stick with tie-rod ends. If you want maximum strength and parts that are easy to swap on the trail, quality Teflon-lined Heim joints might be a better choice for you."

This is yet another example of how different people can get different results from the same product.

I have 2 main issues with mine.

1, The least of which... I could not find a male/female threaded rod with correct length and diameter. A friend of mine is a certified welder so he welded the ends to the rod and that was "ok", but it will obviously never adjust.

2, my tie rod ends were almost identically sized to the spindle and had to be lightly pressed into place. Which caused them to become really loose and I dont like that at all.

Maybe I need to start from scratch but I really don't know where to find the male/female rod in the correct length and size.

It all still seems MUCH better than the original "spring and ball" setup. Mine was so bad that I have no idea how it didnt fall off the little nub that was left of the ball.

Chad,

Is the size you need on this ?:

http://www.rbcbearings.com/literature/pdfs/rbc-heim-
092109.pdf

I know what you mean about the "spring and ball" setup. On my '36 pickup those were very worn out and loose. Fortunately Moog ES29R and ES29L Moog tie rod ends were a direct fit on the tie rod and I made a drag link from a piece of round bar that fit the Moog parts also.

Speedway Motors and probably others like Summit Racing and Jegs probably also list spherical ends. They are very widely used. I don't know why some here are so critical of them.

The Four Wheeler Network forum talks about how durable they are.:

http://www.fourwheeler.com/how-to/131-1306-steering-you-straight-heim-joints-vs-tie-rod-ends/

The "spring and ball" setup in the condition which you describe, was not greased at the recommended intervals.
The recommended interval is every 1,000 miles. If you are traveling mostly on pavement rather than dirt roads, you can stretch that interval substantially.
How many miles does one expect to get out of a Heim joint which has no provision for lubrication? Are they strong, articulate further, look cool? Yes, yes, and yes. Will they outlast the properly maintained old "spring and ball" ends? No, no, and no.
The correct answer to which to use depends on what you need, and for how long you want it to last.