Originally Posted by
Lord_Darkhelmet
I'm having trouble getting the car to be smooth and less twitchy. I have changed the car to run a transverse battery by using the pivot assembly and upper deck from a 12r6. Only other change is the shock, using a one from a 12r6.
We run on CRC black carpet and I'm using the CRC spec tire. The car is not easy to drive and likes to lift the rear inner wheel. Its so responsive just breathing on the steering makes it react hard.
I have tried a soft setup like Keven H but it seems to make it even more aggressive. Soft side springs and heavy tube lube (20k) make the rear wheel lift problem even worse. I was running the dynamic caster block at 10deg and changed it to 5deg, this was the only adjustment which made the car somewhat easy to drive. I have no idea why a soft rear setup is not helping. A fellow racer has a CRC car running soft setup and the car is super smooth to drive.
Attached is my current setup that is somewhat driveable. I hope someone can see something I missed. The only thing I was thinking was to remove the 1mm lower arm spacer and make the front end narrower. I have also tried a high amount of steering expo and turning down the dual rate.
When looking at other setups online pay close attention to what class they are from stock (17.5 or 13.5) or Mod. In my experience setups developed from the Modified category are too aggressive for running in stock as the modified cars need help to scrub off the much higher corner entry speed. In stock the same setup just makes the car super twitchy and slower overall!
For years I struggled to get that twitch out of my R5.2 when running in stock, but here are a few things that have helped me:
Went to Maximum Static Caster
Reactive Caster to Middle setting (5°)
Wider Front Track (Lower Arm Spacers - 1mm)
Toe Out (Between 1° - 2°)
Decreased Bump Steer (2mm under the silver ball-studs on steering knuckles)
Larger Scrub Radius (Front Wheel Spacers - 1mm)
No Pod Droop
Heavier Shock Fluid (35wt currently)
Heavier Center Spring (AE Gold)
Wider Rear Track (Run at the max 172mm)
I've also tried flattening the shock as others have suggested, but didn't like the feel and have since reverted back to the max angle I can get away with.
An important point worth noting is I full sauce my front tires for the same duration as my rears due to some bad experiences with gumming. So just keep that in mind.
Good luck and keep us posted on your results!