> As others have pointed out, there is a lot more going on in cornering than
> just the diagonal weight jacking caused by steer (acting through the
caster
> angle). Here are two that can be separated out--
> Lateral weight transfer distribution:
> The frame is not torsionaly stiff and many karts are adjustable for
> stiffness. In addition to the frame-spring, tires deflect under load so
> there are four more "springs" in the system, and these are nonlinear. All
> of these contribute to the Lateral Weight Transfer Distribution (% carried
> by the front pair of wheels vs % carried by the rear pair) and have
> something to do with determining if/when an inside wheel will lift
> off the ground.
> Total weight transfer:
> And you don't seem to have mentioned the total lateral weight transfer
> caused by the lateral acceleration. This is a function of your center of
> gravity location (in x, y, z coordinates, moves as you lean sideways, etc)
> and the effective track width at the CG location -- wider means less
> total weight transfer and thus less tendency to "bicycle" the kart (other
> things equal, which they never are!)
> Our book contains several chapters on these topics in much greater detail,
> including equations to calculate many of them--and, yes, it has been used
> by successful kart racers.
> -- Doug Milliken
> www.millikenresearch.com/rcvd.html <--for best service, buy direct from
SAE
> > x-no-archive: yes
> > Guys,
> > I think I've finally worked out the kart handling equation, and how the
> > weight transfers. I just don't know whether I want as much weight
transfer
> > as possible, or as little.
> > There are 2 conflicting ideas confusing me:
> > The first thing is in a straight line. Under acceleration (rear wheel
> > drive), the more rearward weigh transfer there is, the harder you can
> > accelerate. Similarly the more forward weight transfer, the harder you
can
> > brake (assuming you have front brakes). So it seems that you want the
weight
> > over the wheels that are doing the work.
> > What I don't understand is sideways weight transfer in cornering. It
seems
> > that the less sideways weight transfer you have, the better you can
corner.
> > Can someone explain this to me, please?
> > Here's how the weight shifts on a kart...
> > (The front end geometry on my TKM is fixed, apart from the track width,
and
> > toe angle. The rear track width is also adjustable.)
> > When you turn the front wheels, the inside stub axle angles downwards,
and
> > the outside one angles upwards.
> > This means that the wider the front track, the more roll you get on the
> > chassis, for a given rear track width. This roll causes the inside rear
> > wheel to lift. Because the inside wheel lowers and the outside wheel
rises
> > (relative to the chassis), widening the track will actually increase the
> > weight transfer to the outside tyre.
> > At the rear, the wider you have the rear wheels apart, the more the rear
end
> > rises when the front wheels are turned, transferring weight forwards,
and
> > the more the inside wheel lifts.
> > So, the wider the front, the more weight transfer there is to the
outside
> > wheels, and the wider the rear, the more weight transfer there is to the
> > front wheels, and the outside wheels. I just need to decide how much
forward
> > and outside weight transfer is required.
> > If I need minimum weight transfer for maximum grip, then maximum grip
will
> > occur when the front and rear tracks are as narrow as possible, provided
the
> > inside rear lifts enough not to cause understeer, by pushing the front
end
> > straight on.
> > If I need maximum weight transfer for maximum grip, then maximum grip
will
> > occur when the front and rear tracks are as wide as possible, provided
the
> > angle of the outside tyres to the track is not too great.
> > Help! :-)
> > Thanks.
> > R.
