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Old 11-24-2013, 04:58 PM   #571
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Front ride height maybe? Might be digging in at the end of the straight since that probably is the part of the track where the weight is shifting the hardest... maybe.
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Old 11-24-2013, 06:28 PM   #572
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Quote:
Originally Posted by rossb View Post
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?
Stock or mod?

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
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Old 11-25-2013, 04:19 AM   #573
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Originally Posted by flameoutgarrett View Post
Stock or mod?

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
17.5 stock blinky. Stock build, stock springs, stock ride height, a few mm of pod droop, stock arm mounts and shims, Jaco Magenta with sauce.

I was attempting to take the turn off the throttle, which is why I asked if I was driving it wrong. Thanks.
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Old 11-25-2013, 05:04 AM   #574
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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.
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Old 11-25-2013, 05:14 AM   #575
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Chunked rear tire?
Rear tire coming un-glued?

And what Jay Bee says. Try 1mm of pod droop.

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Old 11-25-2013, 08:27 AM   #576
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Quote:
Originally Posted by rossb View Post
17.5 stock blinky. Stock build, stock springs, stock ride height, a few mm of pod droop, stock arm mounts and shims, Jaco Magenta with sauce.

I was attempting to take the turn off the throttle, which is why I asked if I was driving it wrong. Thanks.
What is the actual ride height of the car and how large are the tires?
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Old 11-25-2013, 11:17 AM   #577
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I was racing it like this:
  • 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).
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Old 11-25-2013, 11:58 AM   #578
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Quote:
Originally Posted by rossb View Post
I was racing it like this:
  • 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).
I would check the pivot ball links and tweak
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Old 11-25-2013, 03:08 PM   #579
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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.












Quote:
Originally Posted by rossb View Post
I was racing it like this:

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).
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Old 11-25-2013, 03:41 PM   #580
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Quote:
Originally Posted by rossb View Post
I was actually mistaken, it is 756g w/o the body and 805g with the body. Please see the attachments.
looks like the body is rubbing on that FAT wire you have
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
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Old 11-25-2013, 04:01 PM   #581
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Those front tires look a lot bigger than 42 mm
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Old 11-25-2013, 04:20 PM   #582
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Originally Posted by flameoutgarrett View Post
Those front tires look a lot bigger than 42 mm
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
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Old 11-25-2013, 04:32 PM   #583
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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
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Old 11-25-2013, 05:30 PM   #584
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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.
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Old 11-25-2013, 07:20 PM   #585
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Quote:
Originally Posted by rossb View Post
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
You really need nice clean, secure profiles on foam tires
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
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