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Old 12-13-2001, 07:58 PM   #1
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Default How to fix understeer?

Hi all,

I am having problem with my Tamiya TB evo. It tends to understeer at turns. It doesn't turn as much as I wanted it to when some throttle is applied to it (as it accelrates out of turns it tends to run into walls instead of turn inward towrad the straight).

Is there a way to fix it? I am using a very good servo it's a Futaba Digital S9450. It centers all the time and has tons of torque. So it shouldn't be the servo.

Does the toe-in degree of the hub effect turns in anyway??
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Old 12-13-2001, 08:30 PM   #2
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Default understeer

I'm no expert with the car you have but if you want all the help you can get post everything about your car so the people who use it can help you out. Give details of your complete set-up, what type of track you run on with description of its surface, current tire/insert combo or foam tire you are running. Also describe the type of understeer, occurs when entering, middle, or exiting or does it understeer on-power or off-power.

It seems like lot of info. but its necessary if you want to get a good diagnosis on ways to get rid of that understeer.
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Old 12-13-2001, 09:40 PM   #3
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More steering---

-softer shock oil/ springs front
-harder oil/springs rear
-front 0 or1 degree toe-out
-less rear toe-in...side note...never use toe-out in the rear
-more caster to produce more steering out of turns
-softer front inserts (rubber tires)
-softer front foams (foam tires)
-harder rear inserts (rubber tires)
-harder rear foams (foam tires)

There are other options, but I am tired and that's all i can think of now....
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Old 12-13-2001, 09:50 PM   #4
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wonderboy is right. what tires/inserts are you using? what's your toe-in up front? what's your travel limiter setting in your radio?

i have a tb evo and most of the time it steers okay. i have a little oversteer but i like it that way. this is my setup for a semi prepared track (ha! parking lot 8):

about 1 degree toe-in, using sorex 36r with tamiya hard inserts, 60wt oil/blue springs upfront 40wt oil/red springs at back.

hope that helps.
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Old 12-13-2001, 10:11 PM   #5
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Almost forgot... do you have enough off power steering?? If so try adding more droop to the front.

If the droop is set to high (less down travel), when you accelerate the rear end squats (like a drag car) and the front end raises, the suspension arms reach the limit of up travel and begin to loose traction, which causes understeer (push).

Most of the other options listed above will cause an off-power oversteer condition, which inturn can cause the rear-end to break traction while braking. If you don't have one invest in a droop guage...Associated makes one for under $5 that works well.
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Old 12-14-2001, 07:30 AM   #6
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I'd start out with a slightly stiffer spring on the rear.
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Old 12-14-2001, 08:52 AM   #7
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Less caster will give you more off power steeing. The first things I would try would be giving the front more droop and trying a stiffer rear spring.
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Old 12-14-2001, 10:47 AM   #8
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Default Re: How to fix understeer?

Quote:
Originally posted by TRF-Powered
Hi all,

It doesn't turn as much as I wanted it to when some throttle is applied to it (as it accelrates out of turns it tends to run into walls instead of turn inward towrad the straight).
I agree with ImpactPlayr and most importantly with the caster suggestion- Increase your front caster if you can since you mentioned it is pushing on throttle. Also make sure you have enough dual rate on your radio turned up. There are a lot of good options here to correct it- just don't overdo it at one time.
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Old 12-14-2001, 03:52 PM   #9
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what about rear antisquat? i dunno if that's an option on the evo, but i thought i'd throw it out there.
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Old 12-17-2001, 11:12 PM   #10
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You can try the following set up.

Rear:
Ball Diff
Camber link on the lower Hole
700 Tamiya Weight Oil
Blue Tamiya Springs
Modify the front anti-roll bar and put them in the rear.

Front:
One Way
300 weight Tamiya Weight Oil
Yellow/Red springs Tamiya Springs
no antiroll bar.

This setup is what the guys in Japan are running and i have tried it. It provides a very nimble driving feel but take note that traction is a must for this setup to work properly.

Cheers
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Old 12-17-2001, 11:13 PM   #11
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You can try the following set up.

Rear:
Ball Diff
Camber link on the lower Hole
700 Tamiya Weight Oil
Blue Tamiya Springs
Modify the front anti-roll bar and put them in the rear.

Front:
One Way
300 weight Tamiya Weight Oil
Yellow/Red springs Tamiya Springs
no antiroll bar.

There is no optional caster blocks for the TB-EVo so the changes in that dept is a little difficult to achieve.

This setup is what the guys in Japan are running and i have tried it. It provides a very nimble driving feel but take note that traction is a must for this setup to work properly.

Cheers
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Old 12-18-2001, 12:07 AM   #12
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Ok here is my set up:

60W assoicated Shock oil for both front and rear,
Tamiya Blue spring at front, white at rear
0 degree toe-in front, 1 degree toe-in rear,
Sorex 36R with Tamiya hard black insert.
the ride height is about 5mm all around


I have no problem with off-power steering, the understeer happens when i'm trying to acclerate out of the corner. The surface that i'm running my EVo on is Asphalt, pretty rough surface.

So anymore input and suggestions??

thanks for all, that reads and answers to this topic!
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Old 12-19-2001, 09:02 PM   #13
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this should work on all cars with understeer.

1 use lighter oil all round, 350 to 400, use rear sway bar only. This should bring you back more steering out of corner.

2. Lay down the front shock positiion.

3. Use less caster on the front and 0.5 front toe in if other doesn't work.
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