It’s been a long time in between updates for Project Tundra. Most of the time Project Tundra is the garage’s muscle. Moving big parts and towing cars is what it’s mostly used for, but every once and awhile we take it out for some off-road fun. One day we were commuting to work when suddenly one of the springs on our King shocks exploded into around 20 pieces without warning. This was simply being driven down the street, not even hitting any bumps or potholes. When the spring exploded the truck slammed down and bent the shock shaft to where the shock was stuck in the down position, so we could not just change the spring. We inquired at King if we could have our shocks serviced and repaired and they told us it would be 6-8 weeks before they could even look at them. That was not going to cut it, as we need our truck. Fortunately we had met the guys at Icon Vehicle Dynamics at a SEMA event and they had told us to call them if we ever needed anything. This could not have come at a better time.
Being suspension guys we really wanted to have the ability to adjust the suspension of our truck. Our King shocks were adjustable for compression, but we have always felt they could use a little more rebound. Our zero offset wheels made our suspension links effectively over an inch longer, which changed our motion ratio enough for them to feel under damped in situations where we really G-outed the suspension. So we opted to start with Icon’s stage 9 suspension system and build from there.
The first part of the system is Icon’s 2.5 Series front coilovers. These shocks have a generous 2.5″ piston for more heat dissipating fluid capacity, more room for a valve pack on the piston and more bearing area for durability.
The Icon 2.5 shocks have an eye type upper bearing. This allows for a longer shaft with more travel, while maintaining a shorter body that fits within the confines of the stock shock tower. The anti corrosive cad plated adjusting collar for the chrome-silicon Eibach spring is on top, where it is more protected from rock hits. The coilovers are adjustable from 1-3 inches higher than stock.
The large remote reservoir adds to the fluid capacity for better cooling. Inside there is a floating piston that keeps the shock fluid separate from the nitrogen gas that pressurizes the shock. Running the shocks at about 250 psi reduces cavitation when the fluid is forced through the valves at high velocity. Inside the reservoir is Icons CDC adjustable compression damping valve. This adjustment mostly affects low speed compression damping which controls roll and dive under braking. There are 10 clicks of adjustment here.
To upgrade our Stage 9 system we added Icons S2 Stage 3 front secondary shock system. This adds a set of 3″ remote reservoir external bypass shocks to fortify the coilovers. This upgrade doubles the amount of damping capability and drastically improves off road performance. The external bypasses give position sensitive damping. The external bypasses have a ride zone, a big hit zone and top out zone. They act like an internal hydraulic bump stop and soft top out. Adjusters on the bypasses give you independent adjustment of compression and rebound damping. The trick is to use the compression adjuster on the coilovers to control body lean and nose dive, while using the adjusters on the secondary shocks to control response on big hits.