Associated RC 12 R5.2
#572

I was running my car on a track yesterday that had a long straight followed immediately by a 180 degree turn. I ran the car wide open for 3/4 of the straight and coasted for the last 1/4. When I went to make the turn off the throttle at the end of the straight the car had a very strong tendency to snap into a very quick 180 and come to a complete stop facing the opposite direction. The car seemed to handle properly for the rest of the track. I did not notice any other cars exhibiting this behavior. Is this a setup issue or was I driving it improperly?
What's your setup?
Regardless you should never really let off the throttle, if you do all the weight is on the front and will whip around no matter what
#573
Tech Regular

I was attempting to take the turn off the throttle, which is why I asked if I was driving it wrong. Thanks.
#574

How much front droop do you have? What size are your tires? A few mm of pod droop is excessive; try 1 mm. Also try black/yellow for 17.5 blinky; magentas are typically a mod tire setup. But without having your car in my hands it's hard to see if everything was built correctly.
#576

What is the actual ride height of the car and how large are the tires?
#577
Tech Regular

I was racing it like this:
I just shortened the shock and added more shock spring preload. The rear is now as follows:
- Front tires are 42mm.
- Rear tires are 45mm.
- Front chassis ride height is 3.5mm measured at the very front of the car
- The front tires start to come off the ground when I raise the front chassis to 5mm (1.5mm front droop).
- The ride height at both sides of the chassis is 3mm measured at the middle of the car.
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 5mm (2mm droop).
- The car is on the heavy side at 805g with the body on.
- The car is level on a MIP tweak station and the rear pivot moves freely.
I just shortened the shock and added more shock spring preload. The rear is now as follows:
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 4mm (1mm droop).
#578
Tech Initiate

I was racing it like this:
I just shortened the shock and added more shock spring preload. The rear is now as follows:
- Front tires are 42mm.
- Rear tires are 45mm.
- Front chassis ride height is 3.5mm measured at the very front of the car
- The front tires start to come off the ground when I raise the front chassis to 5mm (1.5mm front droop).
- The ride height at both sides of the chassis is 3mm measured at the middle of the car.
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 5mm (2mm droop).
- The car is on the heavy side at 805g with the body on.
- The car is level on a MIP tweak station and the rear pivot moves freely.
I just shortened the shock and added more shock spring preload. The rear is now as follows:
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 4mm (1mm droop).
#579
Tech Elite

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Hey rossb,
Try This setup below But before you hit the track put your car on a Tweak board, check the tweak.( From the looks of the picture your tires looked chunked up) That could also aid in a I'll handling car.
Not sure what your budget is for tires you may want to trim them down. With Larger tires on a high bite track the foam wants to fold over and cause the car to handle erratic.
Look at the setup I enclosed I should put you in the right direction hope this helps.
Try This setup below But before you hit the track put your car on a Tweak board, check the tweak.( From the looks of the picture your tires looked chunked up) That could also aid in a I'll handling car.
Not sure what your budget is for tires you may want to trim them down. With Larger tires on a high bite track the foam wants to fold over and cause the car to handle erratic.
Look at the setup I enclosed I should put you in the right direction hope this helps.
I was racing it like this:
If your running 17.5 try these compound tires and cut tries to:
I just shortened the shock and added more shock spring preload. The rear is now as follows:
If your running 17.5 try these compound tires and cut tries to:
- Front tires are 42mm. 39.38 Jaco Black
- Rear tires are 45mm. 41.92 Jaco Orange
- Front chassis ride height is 3.5mm-3.2mm measured at the very front of the car
- The front tires start to come off the ground when I raise the front chassis to 5mm (1.5mm front droop).
- The ride height at both sides of the chassis is 3mm measured at the middle of the car.
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 5mm (2mm droop).
- The car is on the heavy side at 805g with the body on.
- The car is level on a MIP tweak station and the rear pivot moves freely.
I just shortened the shock and added more shock spring preload. The rear is now as follows:
- The ride height at the very front of the pod is 3mm directly below the side springs.
- When I lift the car by the shock cup on the upper pod plate the rear tires start to come off the ground when the rear pod height is 4mm (1mm droop).
#580

You can see the rub marks on the blue wire
There's lots of stuff going on in that pic that would contribute to an ill handling car, especially if the grip on your track is decent
Tires are everything in 12th scale

Try trueing them like this, it will make a HUGE difference

Last edited by RedBullFiXX; 11-25-2013 at 03:51 PM.
#582
Tech Regular

I trued them down after that pic was taken.
The car is level on a MIP tweak station and the rear pivot moves freely. I don't think it is tweaked. I am replacing the wire with 16AWG TQ wire and I am also replacing the sensor wire with a 100mm TQ wire
The car is level on a MIP tweak station and the rear pivot moves freely. I don't think it is tweaked. I am replacing the wire with 16AWG TQ wire and I am also replacing the sensor wire with a 100mm TQ wire
#583

I had my reactive caster mount drop on one side, your gonna have to go through it very carefully, it can be many things, if it was your tires you would be flipping every corner, something is not as it should be, check the front end and make sure everything is the same from left to right side, my guess is something in the front end is bent/ where it shouldn't be
#584

I had a front bulkhead bend once that made the car do what you are describing. Take it of the car and remove the lower arm and anything else and put it on a flat surface and see if "rocks" or is flat I used a straight edge(ruler) across it,also check the rear bulkheads,the motor mount bulkhead can bend/tweak in a hard enough hit.
#585

If the tire becomes ever so slightly unglued from the edge, it can cause a car to be very erratic
More rounded edges chunk less than high sidewalls
Check tires after every run, even clean runs
High grip tracks tend to pull foam off the rim, from high loads under hard cornering, 180 turns are very high load corners
There is NO setup to fix a tire issue
To the original question of how to drive correctly
You want to drive the car in a way that gives you the best time in 8mins, however that works best for you, don't be so focused on the one hot lap