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Old 11-09-2009, 11:05 AM   #1
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Default General Setup Question Help, getting tail end to stick

Posted this in the VTA thread, but I figure this is probably a general thing that onroad touring guys can answer in general, decided to break it out here:

ok, so around the track, I worked on the car to get the rear planted. not being a setup guy, I used info from a website that had common setup advice as to changing certain items, etc. would do to the handling of the car. I got the car to almost do exactly what I want. It had A LOT of steering, I just need the rear to stick alittle more.

if I turn hard enough, I can break the rear tires free and drift it around a turn, other guys there cars stay stuck basically to the track. The problem arises on a long sweeper that at times if I let off the throttle a bit the rear end could come around. Also, it kind of "chatters" when the rear is about to break free. I even managed to traction roll once so it has grip I am thinking, just that one rear area issue.

So, basically need to know, in general, what should I change if I want the rear to stick more on the car?

My car is different than others, so I can't just post and say give me a setup for a TC3, etc., but here is some general info i can post that I settled on:

starting setup:
- Pistons 1.1 front and rear
- 35W oil front
- 30W oil rear
- Heavy springs (front heaviest spring I have)
- medium springs
- 8mm front and rear ride height, no droop set
- rear link fully angled and 1 short of full length
- 5 degees of caster in castor blocks
- 2 degree rear toe in

this setup was pretty much what it came with from a guy who had the car before running touring car foam.

I then went to:

- 40Wt Front Losi oil
- 25Wt rear Losi oil
- softer rear springs (not sure ratings exactly, have 1 spring softer available I think)
- 5mm front and rear ride height and droop set at that level
- Move rear upper shock position inward (no more holes available, basically over 2 holes)
- Moved front upper shock location outward 1 hole (2 more holes available)
- 7 degrees of caster in caster blocks
- 3 degree toe in
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Old 11-09-2009, 11:09 AM   #2
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First - asphalt or carpet? spool, diff, or one-way up front? foam or rubber tires? sway bars used?

I would add a little droop and consider reducing your caster to 6 or even 4. Also, make sure your turning circle isn't too tight, you might have to take some dual rate out.
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Old 11-09-2009, 11:18 AM   #3
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?str4 pro with v or x pattern tires
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Old 11-09-2009, 11:31 AM   #4
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Thanks for the responses. Here is more info:

- Running USVTA rules (other than motor)
- Surface is Ozite Carpet
- Standard diff up front, car is shaft drive (have center and diff oneways available)
- no swaybars are being used

If I reduce my caster, wouldn't that make the car hook more? From the little cheat sheet I am using and from what I experienced initially making the change to more caster, it calmed the hooking action down.

Should I add droop front and rear equally, or bias it to towards the rear?

Specifics on my vehicle I am using for the VTA class:

specifics:

- Academy STR4 Pro II shaft drive with graphite shock towers
- Speed Passion GT2.0 Pro ESC with DRRS Full and Timing max
- Tekin 21.5 motor with cool fan heatsink(open motors at track)
- RFI 4000mah 25C 7.4V lipo
- Parma Boss 302 Mustang Body ( I really like the looks of this!)
- Weight about 1500+ grams
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Old 11-09-2009, 11:36 AM   #5
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Well the biggest setup thing you can do on VTA is have clean tires. You must clean them with motor spray after each run. If you aren't doing that then go there before making setup changes. No setup you apply will make up for the dirty tires.

Also, you need to run some droop or the car can't lean as well.

Last edited by or8ital; 11-09-2009 at 11:45 AM. Reason: fixed typo
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Old 11-09-2009, 11:38 AM   #6
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If you're running trans-am tires, your camber plays a huge part because of the rear tires being so wide.

As far as caster goes, the more caster, the more it adds camber as you turn giving you more steering mid-corner (for the most part).

I would start with locking down a diff and making the front a spool; you'll lose a little steering at corner entry but you should stop the rear from getting loose (you can gain steering back in other ways).

I would start with adding 1.5mm of droop (over ride height) front and back; you'll definitely need to make some adjustments to this I'm sure.
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Old 11-09-2009, 11:42 AM   #7
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Thanks for the info guys. The droop was the next thing I was going to look into, just wasn't sure what is common for a setting, etc.

The diffs front and rear are about the same in tightness, was thinking of tightening the front more like we used to do when I ran 4wd offroad, will definitely do that next.

My tire cleaning and prep is pretty much what the fast guy is doing for the track so I am set there.

Thanks again! Other than this though, the car has been great and is very durable.
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Old 11-09-2009, 12:18 PM   #8
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cain since you have a cheat sheet your using look at the xray setup guide it helps http://www.teamxray.com/teamxray/sho...p?file_id=2525
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Old 11-09-2009, 01:02 PM   #9
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big thanks! definitely the kind of thing I need. Much more detailed than what I am using right now.

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Old 11-09-2009, 01:39 PM   #10
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Quote:
Originally Posted by 20 SMOKE View Post
cain since you have a cheat sheet your using look at the xray setup guide it helps http://www.teamxray.com/teamxray/sho...p?file_id=2525
+1 - I have a copy that I keep with me all the time.

I also use this as another great resource (although it's not free).
http://www3.towerhobbies.com/cgi-bin...?&I=LXEGG9&P=7
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Old 11-09-2009, 03:39 PM   #11
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i have the xxx main setup guide also,i found it on schumacher forum as a pdf file and copied it but i like the xray one alot more
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Old 11-09-2009, 04:10 PM   #12
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I've struggled with the same thing even with a "normal" car, the vta tires are stange, you could throw jaco blues on it as it and it would feel completely different. What worked for me was doing things to take away steering, what I thought would increase rear grip didn't make as dramatic an effect as taking away front bite does. You can run longer front camber links, almost no front camber, toe IN, sometimes using a very soft spring up front will take away twitchiness and turn-in too.
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Old 11-09-2009, 04:25 PM   #13
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How much of your front tire are you saucing?
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Old 11-10-2009, 07:00 AM   #14
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thanks for the info.

For the front tires I am only saucing about 1/2 to 3/4 of the tires, leaving the outside edge unsauced like I used to do back in touring car many years ago.
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