rec.autos.simulators

by **bengal2** » Wed, 05 Mar 2003 02:55:08

Actually it is the left front that starts the left turn on a kart.
Ackerman also plays a roll which is an adjustment at the point where the
steering columnis conneced to the tie rods. This allows the left wheel
to turn in slightly before the right. The castor lifts the left front
corner of the kart which causes the chassis to twist slightly depending
on how stiff the chassis is. This will transfer weight to the outside
rear.
There are definately many other variables that have been coverd\ed in
this thread that definately contribute, some even more so.

> >When the kart is turning left, the LF tire
> >bites first and lifts the left front corner of the Kart.

> Don't you mean the RF bites first??

> Bill Berry

by **WillyB41** » Wed, 05 Mar 2003 07:53:08

O.K. I see what you're saying. The tire that "bites" in my mind is the RF, but
yes, the way the LF lifts that corner and starts the weightntransfer is
valuable in setup.

Bill Berry

by **Pat Dots** » Thu, 06 Mar 2003 02:16:57

> You must be reading different car dynamics books than me! Tyres do
> not produce double the grip for double the vertical load, hence the
> overall
> weight and weight transfer does (or should) matter.

The tire curves I have seen *are* close to linear up to about 400 lbs.
The total weight of a kart is less than that. The most load a kart
tire will ever see is about 200 lbs (except for high banks).

So, if the curve is really linear for the range of loading, then there
isn't any advantage in reducing weight transfer, is there?

Depends on the track. It isn't hard to figure the right amount of
stagger to run when both ends of the track are the same. If the track
is egg shaped, I would generally set the stagger for the tight corner.

Stagger usually ranges from 3/4" to 1.5". That's not really a lot.

Yes, but the amount of left side bias is small compared to the amount
of weight that transfers on a kart. Typical left side weight on an
oval kart is about 56%. At 1G, a typical kart will transfer around
30% of the total weight of the kart to the right.

Or, better yet for ovals, www.4cycle.com :)

by **Paul Laidla** » Thu, 06 Mar 2003 03:56:32

> > You must be reading different car dynamics books than me! Tyres do
> > not produce double the grip for double the vertical load, hence the
> > overall
> > weight and weight transfer does (or should) matter.

> The tire curves I have seen *are* close to linear up to about 400 lbs.
> The total weight of a kart is less than that. The most load a kart
> tire will ever see is about 200 lbs (except for high banks).

True, but you have only seen data for tyres that are designed to take loads
much higher than a kart so is that true for kart tyres? I freely admit however
that I don't know how far from linear a kart tyre is with a normal load.

There may not be very much, and hence unloading the inside rear
may well be optimal.

So even with an offset seat you still aim to lift the inside rear wheel I take it?

Paul

rec.autos.simulators

Car Physics - Tire Side Bite

Car Physics - Tire Side Bite

Car Physics - Tire Side Bite

Car Physics - Tire Side Bite

Car Physics - Tire Side Bite