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Old 11-04-2011, 08:58 AM   #1
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Thumbs up Handling Question - Steering at High Speed

I'm running a 1/8 4WD off-road buggy (make unknown, I got it second-hand) with a Force 28 engine. I use it only for bashing, usually on short grass. It seems pretty quick.

When running at speed (let's say >60% of max speed) the steering is really lame; the turning circle is absolutely huge. Slow down to <60% of max speed and it really tightens up.

I've upgraded the steering servo to a high torque one and am confident that isn't the problem. I have also reduced the toe-out at the front (It was about +5' and I have now reduced it to +3') but haven't been able to test it out since the adjustment to see what difference this makes.

Tyres are good, plenty of grip left etc.

Is there anything else I can adjust to try to improve high speed steering and give it slightly more "bite"?

Many thanks.
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Old 11-04-2011, 06:20 PM   #2
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Sounds to me like you have found physics. Slow down if you wanna turn, go fast when ya don't. Carries over to real vehicles 1:1 as well.

You could try to add weight up front. But turning radius increases as speed increases.
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Old 11-04-2011, 06:27 PM   #3
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Quote:
Originally Posted by b17flyboy View Post
I'm running a 1/8 4WD off-road buggy (make unknown, I got it second-hand) with a Force 28 engine. I use it only for bashing, usually on short grass. It seems pretty quick.

When running at speed (let's say >60% of max speed) the steering is really lame; the turning circle is absolutely huge. Slow down to <60% of max speed and it really tightens up.

I've upgraded the steering servo to a high torque one and am confident that isn't the problem. I have also reduced the toe-out at the front (It was about +5' and I have now reduced it to +3') but haven't been able to test it out since the adjustment to see what difference this makes.

Tyres are good, plenty of grip left etc.

Is there anything else I can adjust to try to improve high speed steering and give it slightly more "bite"?

Many thanks.
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Old 11-05-2011, 01:26 AM   #4
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Also even with more aggresive tires, at higher speeds your car will just rollover when trying to turn so tight.
Like limywidget said its physics and thats not something you can change.
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Old 11-16-2011, 05:44 AM   #5
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I hear what you say about Physics but this is more than that.

I have a couple of my friend's cars (1/10 off-road buggies - one 2WD, one 4WD) at the moment (been fixing a few things on them). Their turning circle, whilst comparable at low speed, is very noticably tighter, at high speed.
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Old 11-16-2011, 05:54 AM   #6
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It has lots to due with your tires. It the wheel throw is just plan slow then it could be your steering servo not having the torque needed to over com e the physics. Or the other thing is the geometry of the suspension. You have many variables and you need to weed them out one at a time. but as the others have said you have to slow down typically to make a turn.
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Old 11-16-2011, 06:44 AM   #7
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Quote:
Originally Posted by b17flyboy View Post
I hear what you say about Physics but this is more than that.

I have a couple of my friend's cars (1/10 off-road buggies - one 2WD, one 4WD) at the moment (been fixing a few things on them). Their turning circle, whilst comparable at low speed, is very noticably tighter, at high speed.
Not sure it's fair to compare 1/10 and 1/8 scales. I'm sure my mini 18 will turn tighter than a 1/10 scale.
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Old 11-16-2011, 12:17 PM   #8
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Did you try to tighten up on your servo-saver? Can you see if your front wheels are staying turned at hi speeds? If they are, go with a less bite tire in the back and more grip in the front. Sounds like it might be ...pushing the front around the turns, let the backend rotate.
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Old 11-16-2011, 02:10 PM   #9
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Did you try to tighten up on your servo-saver?
+1 on this. Seems to be a fairly common occurrence. It's the threaded collar on one of your steering posts. Over time, that collar can back off. Look at how far your steering moves when you have the front tires lifted off the ground. Then compare that to how far the wheels move when on the ground. If the steering throw is less when the wheels are on the ground, you need to tighten up your servo saver.
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Old 11-16-2011, 02:23 PM   #10
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Lots of people have a tendency to try and mechanically steer as much as they can when they are not getting enough steering. What's really happening is that you are making things worse by increasing the slip angle and your tires can't make full use of its side bite. I used to do this on high speed sections too. What I found is to try and steer the car with the least amount of wheel angle. Driving like this taught me to be smoother on steering and increased my overall lap times/consistency.

Tire choice is also important, and so does ackermann.
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Old 11-16-2011, 02:41 PM   #11
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Check the diff oils, thick rear diff oil will keep you from turning at high speed, a center diff that is unloading on power will cause a push at speed, also the front caster angle could be misadjusted for what you need. a more laid back angle on the front will give you more high speed steering.
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Old 01-17-2012, 09:41 PM   #12
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Quote:
Originally Posted by Zao18 View Post
+1 on this. Seems to be a fairly common occurrence. It's the threaded collar on one of your steering posts. Over time, that collar can back off. Look at how far your steering moves when you have the front tires lifted off the ground. Then compare that to how far the wheels move when on the ground. If the steering throw is less when the wheels are on the ground, you need to tighten up your servo saver.
This is the problem I'm having? Is it better to have a BEC? Is the servo drawing that much off the lipo?
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Old 01-18-2012, 12:54 AM   #13
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No, just check your servo saver.
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Old 01-18-2012, 07:42 AM   #14
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Saver is fine, feels like its losing power? I'm brushless on lipo
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Old 01-18-2012, 07:48 AM   #15
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Quote:
Originally Posted by Limywidget View Post
Sounds to me like you have found physics. Slow down if you wanna turn, go fast when ya don't. Carries over to real vehicles 1:1 as well.

You could try to add weight up front. But turning radius increases as speed increases.

+1 Physics 101
Think of your real car. You can make tighter turns the slower you go vs trying to turn doing 80. Why would a r/c be any different?
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