I see this all the time at the track. Someone brings their brand new 4wd and noses over on the very first jump. Four wheel drive has a different style of driving and this includes jumping. On a typical 4wd short course truck, or 1/8 scale, all four wheels accelerate and stop all together at the same time. The momentum from the tires is transferred to the chassis, and when that chassis is in flight it will pitch up when you accelerate and pitch down when you hit the brake. If your chassis is nose high off a jump, the correction is to simply tap the brake to bring the nose down. If your chassis is nosing down, hit the throttle to bring the nose up. Seems simple enough, but not hardly. Some have the case of the chronic nose dives, and in this article I will cover the most common causes and cures.
- To Much Drag Brake
To much drag brake can pitch the nose down. The simple solution is to take some or all of it out.
- Off Throttle To Soon
Getting off the throttle before the vehicle clears the end of the jump ramp will pitch the nose down. Sometimes I may use this technique on a short steep double jump to set-up for a larger jump that follows, but most of the time I role off the throttle after the vehicle has left the top of the ramp to control the pitch. With a little practice you can land the vehicle on all four by slightly rolling off and on the throttle while in flight.
- Shock Oil and Springs
The wrong spring and oil set-up on the shocks is the trickiest to diagnose and adjust. At times I have even used video tape played back in slow motion to diagnose the problem. If the vehicle has to light of an oil in the rear shocks, the rear chassis will bottom out slapping the face of the jump then rebound quickly making the vehicle pitch forward as it goes off the end of the jump. By going to a heaver oil in the rear, the chassis will not bottom out as hard and the rebound is also more controlled. Think of the front and rear as two bouncy balls attached by a string. If one ball is bouncing higher then the other, it will send the balls going end over end. What makes this the trickiest, and usually a trial and error adjustment, is that the shape, size, and speed of the jumps are all different. Compromises have to be made in spring, piston and shock oil for ALL the obstacles on a track while still maintaining good balance through the corners and rough sections of the race track. My approach to the compromise of setting up for a new race track is to work on the jumps first, then the rough bouncy sections, and then the balance and speed through the corners with adjustments other than shocks and springs.
I hope this helps you find that dialed set-up everyone is looking for and puts you out in front of the pack on race day. Be sure to look for future articles that cover more advanced techniques on jumping and landing for faster lap times.