Buildup -- Step 3: Shocks

In every image I've seen of a basically stock Mad Force, the owner had removed all preload from the springs, and the truck was still sitting very, very high. Incidentally, Traxxas Rustlers and Stampedes (with which I have a lot of experience) have this same problem, and it makes them very bouncy and poor-handling out of the box. With any offroad R/C, you should be able to lift it up, letting the wheels dangle, and not have much pressure on the springs. If there's a lot of pressure (as would be the case with Kyosho's factory settings for the MF), all you're doing is maximizing your ride height, removing available suspension downtravel, and increasing overall effective spring stiffness. None of that sounds good to me. I went ahead and ordered two sets of shorter springs, Kyosho part #IFW32R (fig. 13). This will allow me to set my ride height using the upper spring retainers, instead of setting spring preload.

Fig 13	Fig 14	Fig 15

The manual's shock assembly instructions are very straightforward. You want to use the pistons with the larger holes (see the arrows in fig. 14). In fig. 15, you see the order that the first pieces are inserted to form the lower shock seal. Be forewarned that the white spacer will take a little bit of convincing to go in. The black piece at the end is the thicker of the two types of black round items that come in the parts bag. It's also plastic -- the other pieces (used in a second) are metal.

Fig 16	Fig 17	Fig 18

Speak of the devil! In fig. 16, you see the shock shaft & piston assembly. The first piece that goes on is the black metal washer. To hold the shock shaft in place while firmly tightening the lock nut over the piston, tear off a small piece of paper towel, fold it a couple of times, and wrap it around the bottom of the shaft. Grab the shaft just above the lower threads using needle-nose pliers, with the paper towel piece as a cushion to avoid stripping the chrome from the shaft (fig. 17). The shaft gets inserted into the shock.

When you insert the upper rubber diaphragm into the shock cap (fig. 18), make sure you push it all the way in, with the dome-shaped side facing out towards you.

The first thing I noticed when I tested the smoothness of the shock (before adding oil & closing it up) was that it was dangerously easy to over-compress it, pushing the locknut that secures the piston far up into the cap, where it would squeeze most of the air out of the rubber diaphragm. Fortunately, Kyosho gives you a way to prevent this. Scroll up and look at fig. 14 again. On each side of that parts tree, see the four pieces above the pistons? Yeah, cut off four of those for yourself. On each shock, before assembling the lower eyelet to the shaft, slide one of those pieces (called shock travel limiters) over the shaft, in the direction shown in fig. 19. That will keep your piston from going up all too far.

Fig 19	Fig 20	Fig 21

The shock oil that comes with the kit is surprisingly wattery. It feels like 15-20wt on the Associated scale or 10-15wt on the Losi scale. On a truck as massive as the Mad Force, oil of that consistency will hardly do a thing. To add some dampening, I got a bottle of Losi 25wt oil (fig. 20) to start with. I'll experiment with other weights later on once I actually have a completed truck to try out.

The last few details of shock assembly only take a few seconds, and what you end up with looks like fig. 21. Notice where the upper spring retainer is set. In that picture, there is barely any compression on the spring. If I used the stock spring, it would be very firmly pre-compressed, which, as I said above, wouldn't be a good thing.

Fig 22

Once you repeat this whole process three more times, you'll have what you see in fig. 22 -- four beautiful shocks, ready to set to the side while you move on to other things. I'm sure that I'll need to re-adjust the upper retainers once the shocks are assembled to the completed truck, but that can be done very easily at any time, even in the field. Be sure to ignore Kyosho's millimeter recommendations on this.