HJÆLP TIL OPSÆTNING AF KART
På denne side kan du finde hjælp omkring opsætning af vores karts. I første omgang har vi listet nogle forklaringer omkring sæde, fælge, aksler, hjulnav og en løsningsguide vedrørende greb.
Forklaringerne er på engelsk, men vi vil i nærmeste fremtid sørge for at teksterne bliver oversat til dansk.
Vi vil løbende tilføje vejledninger for andre områder som motoropsætning, karburatorer m.v.
The go-kart wheels currently produced are made from two different alloys, aluminium or magnesium, and must have a maximum diametre of 5”. The width of the wheels may be checked at any point of the competition: the template must pass liberally
until the interior of its top side rests on the tyre.
The template can be introduced in at least three different points of the wheel circumference in order to prevent deformed readings based on local irregularities.
Wheels made of magnesium are about 35% lighter than those made of aluminium, they also bend less lengthwise and so the surface of the tyre functions better, in optimal conditions, with a lower internal air temperature. Magnesium is a very fragile material and even a small bump could break the rims. Aluminium rims are more elastic and thus are more suited to conditions of high grip.
The fixing of the wheels is most important and it should involve a safety system using nuts with split pin or auto blockage.
A fundamental part of the chassis, often underestimated, is the seat and its supports which are important in reaching the required rigidity of the chassis.
The positioning of the seat is very important in that the driver has a total mass which amounts to about 40%, according to his weight and racing category.
Moving the seat influences the position of the frame’s barycentre and weight distribution.
The driver should become one with his seat and for this reason several sizes are made.
The driver’s arms should be free so that during a complete rotation in either direction, the elbows are extended, if not completely.
His legs must be positioned at a correct angle to avoid contracting the ankles into an unnatural position whilst releasing the pedals.
The materials, of varying rigidity and the shims, of varying height, used in the fabrication of the seats, enable adjustments to the torsion-rigidity of the frame.
The seats can be made of carbon or resin, the former being three times as rigid as the latter.
The more rigid the seat and its supports, the faster and more effectively it will work. It is important that the transfer of weight doesn’t happen too late or the kart will be exiting the bend.
Sometimes foam padding is used for the driver’s comfort without exaggerating however, in the quantity used.
Innovations aside, one can tell a go-kart is working well from the vibrations that it transmits to the body.
The weight distribution of the seat is important for the balance of the frame.
Example: 10 kg.
5-7 kg. On left side of seat
3 kg. On right side of seat (engine side)
If more weight needs to be added, it is advisable to place it under the seat at the front;
To gain greater traction it is advisable to place it on the back rest rather than in front of the seat.
Other very important elements are the extra fixing brackets between seat and chassis; these produce a greater force on the wheel, when fixed on axel cases, thus increasing lateral grip.
The hubs are made from aluminium with cnc finish and then anodized. The hubs are very important in the set-up of a kart, the use of longer or shorter hubs is one of the possible ways to vary the free length of axel inflection. The longer the hubs, the
shorter the free position of the axel which can bend. In addition, the longer they are, the better the kart’s grip, the shorter they are, the more free the kart is.
The difference in hub length is thus very important for the kart and can be felt clearly in its set-up.
The axel must be a single piece made of any magnetic material, it cannot have any type of join or hinge or addition of any material which would modify or alter the concept of single piece. It can have a maximum diameter of 50mm, the mounting of a hardening
bush of non magnetic material measuring a maximum of 12mm is allowed on the side of the ring gear. Also allowed is a perforated bush measuring between 30/60mm mounted inside the axel near the rear hubs, it can be made of magnetic or non magnetic material with
the exception of carbon.
The rigidity of the rear axel is very important as a function in its own right but should also be considered in relation to the frame as this determines its rigidity. Most frames have three bearings, two of which are placed on the side of the ring gear to make the right side more rigid. In order to soften the frame and make it more free at the rear, one can free the internal bearing.
Tests carried out on the track and continuous research to improve our products has brought us to develop new rear axels.
Type A = Soft axel. Optimum performance, one must note however, that being soft makes it susceptible to bending in case of accident.
Particularly suited to conditions of much rubber on track.
Standard type B = Medium axel. This is the standard axel normally mounted on all frames.
Particularly suited to conditions of little rubber on track.
Type C = Rigid axel. More rigid than the standard type but very flexible and elastic.
Particularly adapted to high temperature conditions and much rubber on track.
Type D = Extra rigid axel. Harder and more rigid than type C, advisable when more adherence is needed at rear of kart.
PROBLEMER OG LØSNINGER
Most of the people who follow this sport think that the adjustments of a kart can be done in a standardised way. This is a fallacy, there may be a standard set-up, but many aspects must be evaluated only after a track inspection. The track may be very
tyre-marked if there has recently been a race, or it may have rained, or it may have been used for hire-go-karts with hard tyres and so be very slippery, or many other possible cases. It is also common to find several fast drivers all with the same frame model
but with very different set-ups, so this is why we will give you the main tips according to the varying perfomances of the frame.
Under steering 1: the frame tends to broaden the trajectory when entering a bend, so does not turn; this probably is due to too much adherence at the back of the kart so the driver has to steer more than necessary, and in advance, in order to obtain the correct trajectory.
1) broaden the front carriage
2) raise the frame at the front
3) mount the front torsion bar
4) increase the angle of the casters
5) bring the seat forward
6) exchange the rear axel with a softer one
7) check that the convergence is open 1-2mm
8) narrow the rear carriage
9) exchange the rear hubs with shorter ones
Understeering 2: the frame tends to broaden trajectory when exiting bend, so does not turn; this is probably due to too much adherence at the back of the kart so the driver has to steer more than necessary, and in advance, in order to obtain the correct trajectory.
1) narrow the front carriage
2) mount the front torsion bar
3) raise the frame at the front
4) lower the frame at the rear
5) increase the angle of the casters
6) bring the seat forward
7) loosen or remove the extra seat supports
8) exchange the rear axel with a softer one
9) check that the convergence is open 1-2mm
10) loosen screws of rear bumber bar
11) lower tyre pressure
Oversteering: the frame tends to close-in the trajectory and has little grip at the rear; this is probably due to too much adherence in the front of the kart, so the driver has to counter-steer in order to maintain the kart’s trajectory.
1) narrow the front carriage
2) broaden the carriage at the rear
3) exchange the hubs for longer ones
4) raise the frame at the rear
5) move the seat back slightly
6) exchange the rear axel for a more rigid one
7) mount the rear torsion bar
8) remove the front torsion bar
9) tighten the screws of the rear bumper and block the bumber bar
10) lower the frame at the front
11) increase the pressure of the rear tyres
12) reduce the angle of the casters
Oversteering: the frame tends to slip both at the front and at the rear; this is probably due to poor adherence of the kart, so the driver has to counter-steer continuously in order to maintain the kart’s trajectory.
1) exchange the rear axel with a more rigid one
2) mount the rear torsion bar
3) mount the front torsion bar
4) tighten the screws of the rear bumper and block the bumber bar
5) raise the frame at the front
6) increase the pressure of the tyres
7) raise the seat
Wet weather set-up:
1) open the convergence at the front
2) raise the frame at the front
3) increase the angle of the casters
4) broaden the front carriage
5) raise the seat even 2-3cm
6) narrow the rear carriage
7) loosen the screws of the rear bumper and of the bumber bar
8) loosen the bearing of the central axel
9) loosen or remove the extra seat supports
10) exchange the rear axel for a softer one