loose rear and seat postion

[Gregg M Robinson]

Was your oversteer on high speed sweepers? We had a problem in Las Vegas on the two right handers leading onto and down the main straight with understeer that required our driver to lift and therefore be WAY slow on the end of the straight. Using conventional wisdom, we moved the seat forward with no improvement. We then decided to try going back with the seat in order to place more weight towards the rear of the kart so that centrifical force would be higher in the back.

Not being a physicist, I will try to explain our theory this way. Say you are incredibly strong and able to pick your kart up by holding the right rear wheel and the right front wheel and the start spinning the kart around your own axis in some sick blend of ice skating and kart maintenance. Keep spinning around faster and faster until the centrifugal force were to cause you to loose your grip. The side you would loose grip on first (ignoring the ease of grip because of wheel size difference) would be the end of the kart with the MOST weight.

Another likely cause of your oversteer could have been a push kick situation. Your front wheels might have pushed until they grabbed, then the back would kick around. Moving your seat forward could have solved the push problem, and therefore the oversteer reaction.

Okay, so I am very new to this, and I might not know a thing about what I said. Nevertheless, I am pretty flame resistant…. So, flame away!

[Roger Miller]

Very common discussion to break out is the oversteer in the back situation.

Otherwise known as 'loose in the rear"

This always has to start with the information of "where" in the corner does this happen?

When folks get started, they very, very, often say that the kart is loose in back. When my son and I started, we went through this and have been at the track with folks and gone through it with them.

What is usually the case is that the kart is pushing on corner entry, then, the back end steps out in the mid corner or corner exit. But folks don't feel the push. The driver turns, and keeps turning more and more, the kart does turn, and then the back steps out.

So:

What is happening at each stage of the corner?

Where does what happen?

In particular, what do the front tires look like right after the session? If they are grainy, with a pattern that looks like small rice kernels laid side by side (poor description) then you have a push.

Look at the back tires, they should look like a nice even color, and, have a slight balled up look, little beads of rubber, even across the tire surface. Well, that is also how the front should look when things are going well. (another poor description I know).

To take it a step further, if the rears are very pebbly looking, you have too much grip in the back, and this could be inducing a push.

Look at other folks tires as they come off the track. Being able to read the tire surface is a skill that will really help.

If tightening up the front resulted in improvement, then definitely you are dealing with a push to start with.

Mattes, we will be at Atwater this weekend and Dixon next weekend, if you're there, see me and I'll try to help.

[Kevin Van Caster]

What Am I missing?
With TOO much weight to the rear you
end up a Slinging effect,and the tires
can no longer hold it.
Just my take on what it feels like to me.
Kevin

[Matthias Kattanek]

the rear used to be oversteer. bringing the rear in (and the front) showed some improvements. Moving the seat (1 inch to the front) did the big difference.

Here one thing I am irritated by: The book says
"loose rear" -> increase weight on the rear.

I did exactly the different thing. moving the seat forward I guess make the rear lighter.

What am I missing?

mattes

[Christopher Livengood]

The more weight on a tire. The easier it is to overcome its maximum traction.

[Matthias Kattanek]

quote:

---

Originally posted by Kevin Van Caster:
What Am I missing?
With TOO much weight to the rear you
end up a Slinging effect,and the tires
can no longer hold it.

---

Kevin and Gregg I fully agree with you. This goes exactly with what I expirienced. Moving the seat to the front (less weight in the rear), I immediately felt the difference. Instead of oversteer and encountered a little understeer which I then corrected with one more spacer on the front.
From then on the kart felt perfect all day and was fun to drive.

I was just confused by this statement:
"oversteer -> move weight to rear", which is exactly the opposite from what I did.

Roger:
>This always has to start with the
>information of "where" in the corner does
>this happen?

I am not 100% sure on that if it was not loose all the way, I think it started middle throughout the end of the corner. Especially noticable under accelerating.

In regards to the tires. they looked just smooth (not even sandpaper like, sorry hard to describe). Maybe it is due to the fact
it is still kinda chilly and I am using old last season YDSes)

Thanx for the all the response.
mattes