Suspension setup question

[Vbzatty]

Ive converted my Rampage MT into a truggy using baja adapters and tires and TT gears, wing, and bumpers. I love the results, excellent traction and handling but the rear end is uncontrollable. It bounces up over every bump and hill, and when jumping goes higher than the front, making landings usually result in a rollover. I have tried to manipulate it by letting off throttle when jumping or adding throttle, but nothing eliminates it. I was running full firm on the shocks, and thought softening the rears might help but it didnt either. Any suggestions?


Colby

 

[rob64n]

try different wt. shock oil

 

[DemonRC]

This is tricky to diagnose without watching the truck jump. First, do the obvious by making sure the oil in your shocks is doing it's job. Bottom the rear end of you car out and them release it. It should rise back to position with resistance from the oil. If it pops back up and then bounces a little then there's your problem. I know I know it's pretty dam obvious but I just wanted to make sure.


I ran 1/5 scale long before HPI ever got into the game. The first thing I noticed is that 1/5 scales do not jump anything like 1/8 scales. This is just my observation/opinion so don't take my word as if it's biblical script. Anyways, every 5th scale except for the FG types have the engine setup so that the counterclockwise rotating mass of the engine counteract the rotation of the tires. Not many people realize this. If you don't think that engine will torque the car then take the tires off, set it on a 2x4, and rev the engine. It will nosedive. This is why you cannot get the front end to lift when revving the car off a jump. This is also why an FG type is the most controllable jumper of all the 5th scales. Their engines are, in my opinion, in the correct position and the rest of the 5th scale world *cough* MCD *cough* and then *cough* HPI *cough* F'ed up. On my old TT I had a bent chassis plate I used to test out a reverse engine setup. Basically I flipped the engine to the other side. Sure enough I could nosedive or ass plant my TT at will. It jumped 100% different.


OK enough rambling why our cars jump like total crap. What you need to do is go with a heavy enough oil so that the rear end doesn't rebound too quickly before it leaves the jump. If the rear end starts rebounding on the jump as the front end clears you will lawndart it every time. Also, you need to have enough velocity to make sure the car leaves the jump before any rebound occurs. Most guys like to accelerate on the jumps to keep the car level.

 

[Vbzatty]

Thanks for the response. I just finished rebuilding my shocks using hpi parts so now is the time to play with oil weights. I will try 40w in the rear and see if it helps. 20w still in the front?


Colby