rec.autos.simulators

I never heard the term "side bite" in all my years of sim racing.
When I started racing oval karts, I found that this is a big topic of
discussion.  I have also heard it used in other forms of car racing.
Side bite is essentially the amount of lateral force the tire can
provide.  This lateral force generally increases as the tire becomes
more compliant to the road.  Side bite is generally increased by
raising the load on a tire, or reducing air pressure in the tire.  So,
the key seems to be the amount that the sidewall of the tire flexes.

When I started racing karts, and thinking about setups, I could see
that while cornering standard oval karts often transfer 90% or more of
the total weight of the kart onto the right tires.  I thought I was
going to gain a big advantage by running more left side weight bias,
and getting a better balance between the left side and right side
tires in a corner, thereby increasing grip.  But it doesn't really
work that way.  What I found out is that the more weight you get on
the right side tires, the more "side bite" you get, and the more grip
the kart develops.

I have experienced this increase in grip myself.  What surprised me is
that you can have too much grip, and the kart will be slow.  What you
want is a balance that provides enough side bite to get through the
corner, without getting so much bite that you "bind" the kart (which
is another term that I had never heard).

So, how does the idea of side bite reconcile with the idea of max grip
occuring when balancing the loads on the left and right side?

My only theory is that, if you can balance the load more evenly, that
you could run a softer tire compound on the right side.  By doing so
you could maintain the amount of grip generated on the right side, and
increase grip on the left side.  I don't know if this would end up
binding the kart up or not.

In my only experience of testing this theory, I was running more left
side weight than normal for karts, and ran a softer right side tire
compound than anyone else in the race.  I had a big advantage at the
start.  Starting on the pole, I ran off and hid during the first half
of the race.  Toward the end, one guy caught me, but wasn't able to
pass.  My tires didn't go away since my lap times weren't going up, he
just got faster toward the end.

I must be really bored!  Racing won't start again here in Indiana for
at least another month.  :)  Anyway, I'd appreciate any other ideas on
this subject.

The big learning curve I had this past year was caster/camber. It has gotten
very big in dirt oval karts, and helps a ton in maintaining corner speed.
There are a lot of people running high amounts of camber in the RF tire now
a days.

---------------------------------------------
Thanks,
Aaron Markham

RATE MY CAR AT CARDOMAIN.COM!
http://www.racesimcentral.net/

*RIP Ayrton Senna & Dale Earnhardt*

I don't think they oppose each other. I think it's different with a kart
because they are so light. You can't get enough weight on the tire unless you
"unbalance" it to favor the side you want to have traction.

The binding is partially because of the solid rear axle and the small
circumference tires. That's another reason to lighten up the inside tire almost
to the point of "bicycling" it.

Bill Berry

Without stagger at least, the idea is to lift the inside rear wheel when
cornering at the limit as this gives more grip, with the correct amount
of stagger or a diff this shouldn't be the case. It is critical to get wheel
lift setup correctly as you also need both wheels on the ground for
maximum traxction out of corners. If you look closely you will see
some drivers lean outwards through some corners to lift the inside
rear.

I don't really know much about oval racing however.

    Paul

One idea is that you have to get more weight on the right side tires to
get heat into them.

PD

Small circumference.  Could you go further into why that makes a
difference.  Unloading the LR tire to the point of lifting is sort of a
standard part of current oval kart setup theory, but with the right
amount of stagger, I can't see why the inside tire should have to lift.
  Obviously, with a sprint kart and no stagger, lifting the inside rear
makes complete sense.

Thanks,
PD

I understand what you are talking as far as binding the kart if the
stagger doesn't match the turn.  But I have also heard people refer to
having too much side bite as binding.  It's probably more properly
referred to as being "tight".  The car has enough grip to drive it
anywhere you want.  It's very easy to drive, but it's slow.

Yes, ovals are different.

Thanks,
PD

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.
I suspect it is simply hard to get the correct amount of stagger.
Do the ovals you race at have constant radius corners and are all corners
identical?

I imagine small circumference and tight corners simply means you need
lots of stagger, ie the wheels need to run at a greater percentage speed
difference than if you used larger diameter wheels (like on a car).

Now I think about it I was also under the impression that people use offset
seats on oval karts to transfer weight to the inside?

There is (or was last time I looked) some good setup advice
at www.ekartingnews.com in the forums. You'll have to have
a look through to find the good posts though.

    Paul

There is another reason for lifting the inside tire. IIRC, we used to raise the
RF spindle so when you turned left, the weight transferred to the right front
tire like a teeter-totter effect lifting the LR in the process. This dug in the
RF and really made the kart turn hard. We tried to run zero stagger because
even the smallest amount killed the top speed. This was in a stock medium 5HP.

As far as the seat being offset, it has to be for clearance with the engine.
The driver sits right next to it. One other thing I learned was that the weight
of your head and helmet could help you corner. When going into the turn I'd
lean out a little and let my head roll as if I were looking around a corner. It
actually did make a difference.

Bill Berry

Lifting of the inside rear tire on a kart is pretty standard. It is called a
jacking effect and happens in both oval and sprint karting.  I always
thought it was a simple way to get a kart to turn without having to deal
with the effects of not having a diff in the kart.

Dave

http://members.shaw.ca/wjen/wjen/index.htm

Bengal

Don't you mean the RF bites first??

Bill Berry