Front CVA's (Constant Velocity Axles)
The two most annoying things I encountered with the Mad Force when I first raced it were popping center driveshafts on jump landings and binding front dogbones at the extremes of steering. The "turnbuckle trick" mostly stops the popping driveshafts, but the steering issue lingered on. The problem is that the front wheels can over-rotate on the steering axes, forming an extreme angle wherein the shafts will actually slip into the dogbone slot in the axle input cups.
The easiest way to solve this is to install stops on the steering knuckles to limit the steering throw. As I'd rather not limit my truck's abilities, I opted instead to make fit some CVA's up front to eliminate the binding-prone dogbones. There is no CVA or CVD set available specifically for the Mad Force, so a bit of grunt work is called for. One thing you can do is modify a set of Kyosho Inferno universal axles (or ones from another 1/8th scale vehicle that uses 8mm stub axles), cutting & extending or shortening them as needed with the help of a metal sleeve. For no particularly justifiable reason, I took a different route.
Here are the parts I used:
| 1x DTXC7473 | DuraTrax Universal Dogbone Axle Thunder Quake |
| 2x DTXC7510 | DuraTrax Drive Hub w/Wheel Nut Axis/Nitro Quake/Thunder Quake |
| 4x MR616-2RS-29 | Boca Bearings 6x16x5mm Chrome ball bearings |
Here's a picture of the stock Thunder Quake axle set, from Great Planes:
As you can see, these make a great starting point for customization as the joint ends are separate, allowing the bones to be shortened easily without major surgery. The two problems, however, are that the axles are 6mm (vs. the 8mm axles of the Mad Force), and the dogbone end bulbs are absolutely enormous. To deal with the axle size issue, I simply got new bearings for the front carriers. They're rather expensive at $10 apiece (and you need 4), but they're a no-hassle fix. The dogbone end has to be simply ground down with an aluminum oxide drum bit on the trusty Dremel. The diameter of the bulbs needed to be significantly and uniformly reduced without cutting into the drive pins, and the pins needed to be shortened just a tad. A cheap set of calipers is an invaluable tool for this, and I recommend securing the Dremel to your workbench with some sort of clamping mechanism so that you can keep both hands on the axle for stability and precision. Here's the result:
Here the dogbone has been ground down & sanded, and the end has been trimmed for the left (long) side and given a flat spot to catch the u-joint set screw. Also shown are the new bearings and hex hub. When all of this is installed, the u-joint's pins sit directly in line with the steering axis for maximum efficiency and minimum load:
