Project Tundra: Dirt King Lower Control Arms

As we continue to upgrade the front suspension of our Tundra to make it more durable in off-road use, we focused on a set of improved front coilovers, new tie rods, and knuckles.  We looked a little harder to find a new lower control arm.  We wanted something stronger that would accommodate our bypass shocks and allow the use of a front anti-sway bar.  Although many off-road enthusiasts remove their front bars, we feel that this makes a truck less safe on-road and that a reasonable front bar does not hurt off-road performance. When you look most race trucks run front sway bars.  We also wanted to get rid of the stock rubber bushings and ball joints because they don’t articulate well.  After looking at the offerings from many companies, we settled on the heavy-duty performance lower control arms made by Dirt King Fabrication.

The Dirt King Performance lower control arms are designed to be a direct bolt-on replacement for the stock lower control arms and can be used with any lash-up of parts from stock, to dual shocks with external hydraulic bump stops with limiting straps.  The Dirt King arms are made of laser cut 4130 chrome moly plate and tig welded together. They are considerably stronger than stock.

The Dirt King lower arms have internal gusseting which is tabled and welded externally.  This makes the arms considerably stronger without much weight penalty.

Here is a closer look at the tabbing and gusseting. If you manage to break these arms you probably have worse problems in your rig.  On a serious note, the internal gusseting reduces the chances of a catastrophic failure of the arm that can leave you stranded trailside. Nothing is worse than having to do major repairs in the dirt miles from any help.

The control arms use Delrin bushings.  We liked this feature and is one of the main reasons why we chose Dirt King over others. Delrin has slightly better NVH over bearings and unlike urethane does not get pounded out.  We found that urethane has a pretty limited life in off-road use.   Rubber works decently off-road but the articulation of rubber is limited and when forced to articulate a lot the life is really short.  The Delrin doesn’t have much flex so the entire front suspension rides on either bearings or low compliance Delrin which will make our truck very responsive. Without rubber, you might think the ride will really suffer but this is not entirely true, the friction will be low so the suspension will still work pretty well.

2 comments

  1. People that worry about NVH in an off-road vehicle, or racecar, are doing it wrong.

    There are all purpose vehicles, and there are single-purpose vehicles, and the two should not be confused with one another.

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