Could this be one of the more controversial pieces we have ever published? We sure hope so. The concept that the lowly rubber joints would be the preferred choice over the mighty heim joint is blasphemous and possibly a commitable offense.
All those things aside there are definitely cases and places where a good old-fashioned rubber joint is the better option.
On Road Performance
Rubber joints inherently dampen noise and vibration. They have a natural self-centering tendency and offer a smoother ride versus a heim joint.
Heim joints lack any isolation characteristics, they transmit the road imperfections into the frame and directly back to you as the driver. Heim joints don’t last as long on the road without either rebuilding or routine maintenance to keep them operating properly.
Rubber joints are also much cheaper to maintain and replace. Makes hauling loads, changing conditions and more easier to deal with.
Here is probably where I will make the most controversial statements. Rubber joints will outperform a heim joint in all but the most severe off-road scenarios.
The primary reason is traction. Rubber joints have resistance that transfers force back into the tires. Heim joints only resist at the maximum flex and it is a hard stop, there is no energy transferred back into the suspension. Great on a competition rig where there are other ways to regain traction, larger tires, more HP, momentum etc… For your streetable ride that extra force applied to your “shoes” makes traveling off-road much easier.
Rod ends are also rigid. They provide plenty of flex from side to side with the proper misalignment washers but a heim joint has no give. It’s essentially a metal-to-metal connection. This can lead to suspension and frame brackets cracking and even tearing free. Adding a flexible bushing to one end of a control arm can remove some of these stresses but it won’t add life to your heim joint.
Lastly, comfort comes into play again. It’s easy to get beat up off-road when your ride is transferring every bump and imperfection right back to you in the drivers seat. You can go a lot further and drive longer if you isolate yourself from all that abuse.
Stop chasing the competition style suspension systems, stop going cheap and buying low quality heim joint lift kits and hating your decision later. Dealer lots are full of these castoffs from people that buy heim joint or rod end equipped systems and then complain about the harsh ride. Do yourself a favor and don’t chase flex numbers, go for a system that really performs where you want it to.