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Old 04-03-2011, 04:58 PM   #1
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Default TC3 turning question. Spins out one way

I can do donuts if I turn the wheel all the way to the left but from the right it will not do that (it just continues on pushing and doing a large circle). While driving the car on an ozite carpet (or any surface for that matter) it'll oversteer nearly instantly and come around. I'm running on VTA required tires, green rear and I've tried blue and silver springs in front to see if that'd help. The blue helped a bit but something just isn't right. I've got the front diff completely tight but I've tried loosening it to see if it helped but it didn't. I've tried changing the rear diff tension between tight, 1/2 a turn and 1 turn and nothing helped. Tightening the rear completely made it worse. My tweak screws are even, I'm running 40 wt shock oil and I've tried to vary ride height between 5-7mm w/ no change. Currently i'm running no sway bars. The car is within a few grams left to right and front to back. Steering is even and radius is the same left and right when doing a circle. There is no binding in the steering. I'm at a loss here. Any input is appreciated. I got this car used so this has done this from day 1.

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Old 04-03-2011, 09:41 PM   #2
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Not much interest, Hmmmm??
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Old 04-03-2011, 10:54 PM   #3
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Quote:
Originally Posted by TT_Vert View Post
I can do donuts if I turn the wheel all the way to the left but from the right it will not do that (it just continues on pushing and doing a large circle). While driving the car on an ozite carpet (or any surface for that matter) it'll oversteer nearly instantly and come around. I'm running on VTA required tires, green rear and I've tried blue and silver springs in front to see if that'd help. The blue helped a bit but something just isn't right. I've got the front diff completely tight but I've tried loosening it to see if it helped but it didn't. I've tried changing the rear diff tension between tight, 1/2 a turn and 1 turn and nothing helped. Tightening the rear completely made it worse. My tweak screws are even, I'm running 40 wt shock oil and I've tried to vary ride height between 5-7mm w/ no change. Currently i'm running no sway bars. The car is within a few grams left to right and front to back. Steering is even and radius is the same left and right when doing a circle. There is no binding in the steering. I'm at a loss here. Any input is appreciated. I got this car used so this has done this from day 1.

Thanks
Dave
when you said tweak screws, you mean droop screws?i dont set tweak with the droop screws, if its too complicated, take out the droop screws and set the droop with your shock length, making sure left and right shocks are the same. also make sure your hingpins arent binding. i usually use very heavy springs up front and soft in the rear so that the car will be very stable. also run less droop in rear than the front.
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Old 04-03-2011, 11:07 PM   #4
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The TC3 was notorious for chassis tweak as a result of motor heat...lay the chassis flat on a setup board/glass/flat tabletop etc and see if the right rear corner of the chassis is raised up.

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Old 04-03-2011, 11:45 PM   #5
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- Could be a problem with the CVDs. Check to make sure none are broken or missing roll pins.

- Could be an issue with front hub carriers. Make sure if you are running 2 or 4 degree hub carriers that they are installed correctly. If you have one installed with positive caster (facing forward) it can create problems.

- Could be an issue with a "stuck" suspension arm. Remove the wheels & remove the shocks from the rear a-arms (okay to leave shocks on the tower). Lift each rear a-arm and make sure it drops freely.

- Could be an issue of tire/body rub. Check to make sure the tires aren't rubbing inside the body. Try the car without a body to see if the problem persists.
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Old 04-04-2011, 01:26 AM   #6
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Yes i meant the droop screws. Prior to driving the car I disassembled, cleaned and rebuilt EVERYTHING on the car. I backed the droop screws all the way out, no change. I took body off to eliminate possible clearance issues, no change. I checked for free movement of all suspension pieces. I will check the chassis to ensure it is flat. If it is not flat, is there any recourse outside of buying a new chassis? CVD's are perfect as are all bearings. I will check the caster blocks tomorrow.
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Old 04-04-2011, 07:12 AM   #7
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Quote:
Originally Posted by IndyRC_Racer View Post
- Could be a problem with the CVDs. Check to make sure none are broken or missing roll pins.

- Could be an issue with front hub carriers. Make sure if you are running 2 or 4 degree hub carriers that they are installed correctly. If you have one installed with positive caster (facing forward) it can create problems.

- Could be an issue with a "stuck" suspension arm. Remove the wheels & remove the shocks from the rear a-arms (okay to leave shocks on the tower). Lift each rear a-arm and make sure it drops freely.

- Could be an issue of tire/body rub. Check to make sure the tires aren't rubbing inside the body. Try the car without a body to see if the problem persists.
Could also be bad bearings.
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Old 04-04-2011, 01:23 PM   #8
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Check the steering rack for binding
Check that the servo is working properly
Check for a bent or damaged rim; put the car on a stand and give it quarter throttle. A bad wheel will cause the car to vibrate and rotate to one side or the other.
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Old 04-04-2011, 03:27 PM   #9
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Quote:
Originally Posted by pejota View Post
Check the steering rack for binding
Check that the servo is working properly
Check for a bent or damaged rim; put the car on a stand and give it quarter throttle. A bad wheel will cause the car to vibrate and rotate to one side or the other.
steering rack is free, all bearings are free. New rims/tires although I will switch left and right front and rear to see if the problem follows the tires. Servo appears to work fine and moves left to right at the same speed.

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Old 04-04-2011, 11:11 PM   #10
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I disassembled everything and the only thing I've noticed is that the lower front shock bolts hit the rim on full lock to lock but that occurs both ways and is in the front so I really don't think that is the issue. I am concerned that this is happening as I am using the correct 440 screw in there. I am using the outter hole on the front arm when this occurs. Is this typical? I also found out the car has 4 deg front caster blocks. Not that that'd cause an excessive over steer just one way.
If it helps my front "blocks" say F2 and rear says R2-0, whatever that means
Thanks
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Last edited by TT_Vert; 04-04-2011 at 11:28 PM.
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Old 04-17-2011, 10:03 AM   #11
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Played with it some more. I put it on a tweak board and have it straight and level. I put the stock front sway bar up front. It had losi steering knuckles so I put the associated steering knuckles back on with 0 degree caster blocks. Problem still persists. I'm completely stumped now.

Anyone else have any input?? It's almost like the diff isn't spinning freely one way in back but I just rebuilt it (twice)

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Old 04-17-2011, 11:13 AM   #12
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Do look into the diff, thats what first crossed my mind make sure you have a nice new diff nut as that thing tends to lose its hold with time. One other thing is to check all your links and make sure they are equal in length.
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Old 04-17-2011, 11:20 AM   #13
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I would check the steering throw and for the heck of it try swapping rear tires left to right. See what happens.
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Old 04-17-2011, 02:20 PM   #14
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swapped tires left to right and it made no difference. Went through the diffs and readjusted. I had the rear backed out 1/2 turn from fully tight and the front about 3/8ths of a turn. I've tried to tighten the front fully and that didn't make it better or worse. What esle can I look at in the diffs? T hey are smooth and seem ok. I put 2 hole pistons in, running 40wt. Have the rar shocks all the in on upper and out on the arm. Front i have middle up top and outside in front. I have the camer links as high an as long as allowed w/ the car. Blue front/grean rear springs.

A small note: On my asphalt driveway it seems to not do it as much but on my street it does it horribly. Could this all just stem from lack of traction? If so, why would it spin one way but I cannot force it to spin out going right? I may try to get a video up to show the extent of the problem a bit more. I drove another tc3 and it just spun out both ways equally.
Thanks much
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Old 04-18-2011, 03:42 PM   #15
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Well I finally fixed the problem. As a last resort I swapped the diffs and rebuilt them w/ no change. I then proceeded to swap the front to rear shocks and the problem went away completely. I need to measure the lengths of the shocks but something is amiss w/ shock length or something. All 4 shocks had the same rebound and shaft length I thought but I need to double check them now. I did keep the green springs that were in back up front and now the blue springs that were in front are in back. Do you think that alone would be enough to cause the spin out or is it something w/ the shocks themselves?


Thanks
Dave
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