 | Front End Talk
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The front end of your kart is important for correct handling during a race. So spend some time here and get your front end set-up right or you will never be first to greet the chequered flag. It's easy for us to give you the solution or correct set-up change when you encounter a problem, but we believe before you start making changes you need to understand why. This starts with explaining some commonly used terms. We wanted to explain some of the key factors important to steering in a great handling kart. You won't have any say in some of them, as they are angles chosen by the manufacturer in the design of the frame, but it is handy to at least have some idea what makes the kart handle as it does. The most important rule here, is that the relevant angle must be the same on both sides. Toe-In and Toe-Out - This is where the front wheels are closer together at the front (toe-in) or closer together at the back (toe-out). The ideal basic setting is obviously to have the wheels running parallel to each other, but because of the effect of the camber angle you will need to use the toe adjustment later to correct the steering. Ackermann Steering - This is to overcome the problem of the inside wheel requiring a tighter turning circle than the outside wheel when cornering. With the "Billy Cart" steering method of a centre pivot, both wheels have a common turning angle, causing the wheels to skid around corners. By choosing the angle and length of the stub axle steering arms, and by making the steering linkage shorter than the distance between the stub axle pivots, the Ackermann principle is achieved to prevent wheel skidding or tyre scrubbing. Castor - This is the angle of the kingpin bolt when viewed for the side, and together with the kingpin inclination are responsible for the ease or difficulty of steering. Castor on karts is always positive, or the kingpin always leans back at the top. This gives the steering it's self centring ability, and makes the kart more manageable and less likely to change direction without you wanting it to. Camber - Is the angle of the wheels when viewed from the front. If the wheels are leaning in at the top, it has negative camber, or positive camber if the wheels are leaning out. Too much of either is not all that good and we are talking about 3-4mm. Bent stub axles will change the camber angle, so again make sure both axles have the same angles. It would appear that a small amount of camber is good for stability, but you then introduce camber thrust. That is, if you have the wheels leaning in they want to track towards each other. A similar effect is experienced when you lean a bicycle to the left or right to turn, this is called camber thrust. A small amount of toe adjustment is then required to counteract the camber thrust. If you have negative camber, you need to adjust the tie rods to give toe out, but only about 3-4mm. If you need more toe out it is probably better to do something about the camber adjustment. Kingpin Inclination - This is one of the most critical parts of a kart chassis. It is the angle of the kingpin bolt when viewed from the front. Don't confuse it with the camber angle which is the angle of the wheel in relation to the ground. Kingpin inclination causes the wheel to change from negative to positive camber as the steering is turned, transferring weight from one side to the other. This is the reason a kart can turn corners without the need for a split rear axle or differential. After each race, careful inspection of the steering column and tie rods are necessary as they are put under extreme stress not only in normal driving, but also when you receive the occasional bump or off road excursion, very common in close hard racing. Replace or repair any parts that are bent or damaged, and reinforce the steering column at the top end where the steering boss bolts to the shaft. This point is a common point of stress fracture, particularly if you use the steering wheel to pick up the kart on corners. It's important to inspect the steering, even more so if you have had a hard shunt. The last thing you want in an accident situation is the fractured steering column looking at your face after the steering wheel has broken off. Tip one - When assembling your stub axles and kingpins and bolts, use a nyloc nut on your kingpin bolts, as there is nothing more embarrassing then having the front end of your kart fall to pieces just before you cross the finish line. Tip two - All parts must have free movement without free play. Replace any worn bearings and this includes tie rod ends. Tip three - Do a wheel alignment, we suggest you use "Sniper V2" aligners. Tip four - Adjust the steering stop so that the tie rods don't have contact with the steering column on full lock in either direction. Till next time. | 
