Go kart tyre / Vehicle dynamics

[Twonius]

I've heard some pretty weird things about kart behavior recently, like load transfer is reversed etc. Can someone shed a little more light on what makes for a good setup on a kart (cg height and corner weights).

I've heard that the fastest way around a corner on a kart is almost bicycling, is this BS, due ot the locked axle or what?

[kwancho]

I don't know much about hardcore karts, but I have heard from the owner of the indoor kart place that I go to that pitching your weight forward and outside will help lift the inside rear wheel. This allows you to put the power down without dragging/hopping the inside wheel. In theory, at least.

[KU_Racing]

Karting is definately a whole new arena as far as setup goes. Tire pressure and how it affects handling is HUGE compared to the difference it makes in a kart. Ask any good kart mechanic, and they will tell you that any pressure gauge that doesnt read in tenths is worthless. Chassis stiffness and axle stiffness are also huge- things like the sidepods being bolted on and how stiff of a seat is used have large effect on how the kart will handle. Also, it is true that weight transfer is different- you basically want the kart to corner on the outside tires.

[PatClarke]

Hi 2nius,
Kart dynamics are odd. The dreadful compromise that a kart is has led development up what I see as a blind alley. I have been involved at the very top, and yet I hate the way the bloody things have developed.
Huge caster and Kpi angles make it very difficult to get corner weights right, and often the structure of even the best karts is not accurate enough to get consistant corner weights.
The huge caster, kpi and scrub figures makes them jack diagonally at a huge rate, and this is the clue to cornering.
Like anything, get the c/g as low as possible and run the rear track as wide as you can and still get grip and the front as narrow as you can and still turn.
The surest way to go slow in a kart is to consume power in grip. If the kart grips up in the middle of a corner you will bog the engine and be slow.
And like all other kinds of motorsport, practice makes perfect!
Pat

[PatClarke]

Here is a link to an interesting gokart.
Not your average 'Tater digger'
http://www.kartsportnews.com/feat_carbonkart.html
Pat

[mtg]

Reversed load transfer violates the laws of physics, and karts aren't quite that good yet!

If you have a cg above the ground and you have lateral acceleration to the left, there will be an increase in vertical load on the right side tires to resist the roll of the chassis, period. Otherwise the thing would just start log rolling off the track.

[Patrick W. Crane]

I'd guess that you'd want the kart up on two wheel so that it doesn't push into the corners cause of a solid axle and if the inside front is off you don't have to deal with the shit ass steering geometry.

Just a though. not that i have any experience.

[skokle]

Originally posted by Alex Kwan:
I don't know much about hardcore karts, but I have heard from the owner of the indoor kart place that I go to that pitching your weight forward and outside will help lift the inside rear wheel. This allows you to put the power down without dragging/hopping the inside wheel. In theory, at least.

I think that the goal of leaning to the outside tyres is to get temperature in them - which is harder in karts? Increasing the temp in the outside tyres and increasing the vertical load puts you in the optimal slip angle region (assuming you are not over).

I think its different in the likes of F1 where they lean inwards as they already have enough tyre temperature to be at the optimal slip angle.

Do you buy that or am I completely off track?

[Aaron Bailey]

I've raced go karts for about 9 years and have had my fair share of handling experiences with a go kart. The handling issues depend on the tire. A softer compound tire means the kart has to be set up differently then on a harder tire. With a soft tire you would want the entire chassis stiffer, and with a harder tire, softer, with more flex. Many of the new karts use different wall thickness axles, stiffness adjusters in the chassis, and even stiffening bars like sway bars to help effect the handling. Tire pressures make a biug difference too, but not to the tenth of a pound. We have never had a difference between tire pressures in a tenth or two.

The biggest aspect of getting a kart to handle is a good driver:-D