Full Traction gets ahold of a 2007
- Thread starter CLynn85
- Start date
goodtimes
Expedition Poseur
I'd be sold on Full Tractions stuff if they would stop using the damn heim joints. Their ability to retain a true 4 link up front with long arms is damn impressive (FYI, RE, RK, et.al. use a radius arm setup and call it a 4 link). I haven't heard too many complaints about the FT heim joints failing, but I like the cartridge joints that I can adjust when needed, and eventually take apart and rebuild. There is also ALOT more surface area with the cartridge joints, so the shock loads are spread out over an area 2 - 3 times as large as the heim joints, which one would assume leads to longer life (although I have no scientific data to back that up).
goodtimes
Expedition Poseur
Heim joints, AKA Spherical rod end bearings (pictured below) typically have a hard spherical ball in the center, ground flat on each side with a bore through the middle. Around that is typically a teflon or hard plastic sleeve which is either cast or machined to have a very tight fit to the hardened ball. Around the sleeve, is the outer casing, generally with a threaded stud integrated into it. The center ball and plastic sleeve is pressed in from one side, then locked in place with a [typically] swaged in ring. They are not adjustable, not rebuildable. Typically in automotive aftermarket applications, high misalignment washers are added on either side of the heim joint to allow greater misalignment of the joint. Basically these are sleeves that are machined to allow clearance around the outer case of the joint. These are a very user friendly parts. Which is important, because they wear out, and you have to replace them. You won't find these in automotive applications for steering or suspension components from the OEM's, because when they fail, things fall apart...literally. There is no safety with these as there is with ball joints or Tie Rod ends (which is why TRE's and ball joints are what the major MFR's use).
Cartridge joints are the same basic concept...only bigger. Instead of using high misalignment washers on the outside of a sphere that was ground flat (thus reducing the amount of surface area), a cartridge joint takes the sphere, adds 2 'ears', which accomplish the same thing as the misalignment washers on a heim joint, but with only 1 piece now instead of 3. The "ball" of the cartridge joint is typically 1.75 - 2.5" in diameter, compared to 1 - 1.5" for the heim joint. Just like the heim joint, the center ball and plastic sleeves are pressed in from one side, but cartridge joints typically use a threaded plate to hold it all in place. This plate can be adjusted to obtain the proper pre-load on the joint. Over time, if things start to wear, you can simply clean the joint out, re-assemble it and adjust the pre-load to remove any slop. Rebuild kits are available if you need them.
Basically, the heim joints are small in comparison to the cartridge joints. The smaller size equates to a smaller surface area to wear out (and they will wear out). When they do, you buy a new one. The Cartridge joints you simply adjust...but, they are very bulky compared to heims, and typically don't come with a threaded stud integrated into the outer case. These are usually welded to a piece of tube, or you have a threaded stud welded to them after you recieve them.
Cartridge joints are the same basic concept...only bigger. Instead of using high misalignment washers on the outside of a sphere that was ground flat (thus reducing the amount of surface area), a cartridge joint takes the sphere, adds 2 'ears', which accomplish the same thing as the misalignment washers on a heim joint, but with only 1 piece now instead of 3. The "ball" of the cartridge joint is typically 1.75 - 2.5" in diameter, compared to 1 - 1.5" for the heim joint. Just like the heim joint, the center ball and plastic sleeves are pressed in from one side, but cartridge joints typically use a threaded plate to hold it all in place. This plate can be adjusted to obtain the proper pre-load on the joint. Over time, if things start to wear, you can simply clean the joint out, re-assemble it and adjust the pre-load to remove any slop. Rebuild kits are available if you need them.
Basically, the heim joints are small in comparison to the cartridge joints. The smaller size equates to a smaller surface area to wear out (and they will wear out). When they do, you buy a new one. The Cartridge joints you simply adjust...but, they are very bulky compared to heims, and typically don't come with a threaded stud integrated into the outer case. These are usually welded to a piece of tube, or you have a threaded stud welded to them after you recieve them.
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BajaTaco
Swashbuckler
Thanks for the info GT. I am very familiar with heims, but not the cartridge joints. So I wanted to see what your reasoning was for one over the other. Very interesting.
You can indeed replace the spherical bearing and teflon bushing on a heim joint though. It seems to me that maybe they both have their optimal applications. The cartridge may be too bulky for some fitments. But I can see what you mean about the strength. Are you seeing failures of the heims on the Jeep arms? Or is it just the adjustability that is the main factor in using it for this app? That is pretty cool how you can just spin that plate to tighten up the joint. I wonder though, about welding the threaded studs onto the casing. Wouldn't the heat produce a risk of potentially deforming such a small part that relies on being perfectly round?
{EDIT} Now I am realizing that the cartridge joint is what I have always known as the "Johnny Joint". True?
You can indeed replace the spherical bearing and teflon bushing on a heim joint though. It seems to me that maybe they both have their optimal applications. The cartridge may be too bulky for some fitments. But I can see what you mean about the strength. Are you seeing failures of the heims on the Jeep arms? Or is it just the adjustability that is the main factor in using it for this app? That is pretty cool how you can just spin that plate to tighten up the joint. I wonder though, about welding the threaded studs onto the casing. Wouldn't the heat produce a risk of potentially deforming such a small part that relies on being perfectly round?
{EDIT} Now I am realizing that the cartridge joint is what I have always known as the "Johnny Joint". True?
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calamaridog
Expedition Leader
Looks good. 3" and 35" tires sounds about right.
Wanderlusty
Explorer
http://www.project-jk.com/images/teraflex/TERAFLEX_2007JK.jpg
I like the look of this a lot too. Stock wheels, and the tires are tucked under the flares.
I wouldn't be surprised if one or both of those has, or needs some wheel spacers to prevent rubbing, though.
I like the look of this a lot too. Stock wheels, and the tires are tucked under the flares.
I wouldn't be surprised if one or both of those has, or needs some wheel spacers to prevent rubbing, though.
chet
island Explorer
Chris how do you replace the ball in a heim? Also yes a Johnny joint is a cartridge joint but there is other mfg's now other than Currie so Johnny joint doesn't apply.
As for the heims, I have never had a problem with strength only wear and corrosion. The teflon lined ones wear the teflon then get sloppy and the metal on metal ones tend to sieze up then wear the race and the ball!:smilies27
Oh BTW I finally see pics of a Jeep I would buy!!! :wings:
As for the heims, I have never had a problem with strength only wear and corrosion. The teflon lined ones wear the teflon then get sloppy and the metal on metal ones tend to sieze up then wear the race and the ball!:smilies27
Oh BTW I finally see pics of a Jeep I would buy!!! :wings:
BajaTaco
Swashbuckler
chet said:
Sorry, I just reread my post. I meant that there are some heim applications that can be rebuilt whereby the spherical bearing and race can be removed via a retaining clip. (off-road racing shocks being an example) I think typical off the shelf rod-end (heim) joints are probably swaged over the bearing (permanently) or if using a nylon or teflon race, the races are staked in. So in that case, what GT said is correct. Sorry about the confusion.