First up. weight distribution is not a fixed science.
Every driver and every kart will have a weight distribution that is different, possibly even from karts of the same type. This is because drivers vary in how they drive and karts vary in how they respond.
For a light, small driver, the issue may be to get the weight shift in braking to move far enough over the front wheels to allow an effective turn in, for a heavy driver the difficulty may be getting far enough back so that the front doesn't have so much authority that the driver struggles with control.
Hence the fact that the figures vary from 40/60 to 50/50 but are normally in the range of 45/55.
There are a number of ways to calculate weight distribution. However, placing the kart on four scales (corner weighting) is not the most accurate unless you have rigorously checked the kart for being true.
A kart flexes as it goes round the track and it does not always return to exactly the true position. Kart tyres are often of different circumference and therefore of different diameter. The floor on which the scales stand may not be exactly level. The kart will sit stably on only three of its four wheels, but providing the forth wheel is apparently on the scale, you wont know whether the apparent weight differences are due to the floor, the bend in the kart or the weight distribution.
More, the problem may even be the way you sit in the kart. If you lean left or right very slightly, you can watch the weight on the appropriate side go up and down. Indeed, if you are reading the scales yourself, just looking at the scale can lead to movement that alters the readings. (and if the problem is tyre size, then just swapping the tyres will alter the measurements) Swap the tyre and take the measurements again
However, at the moment you have 69Kg (38+31) on the front, 89 kg on the rear, total 158. 69/158 *100= 43.7%. 89/158= 56.3%
If you wish to move weight to get 43/57.
1) Measure the wheel base, from the centre of rotation of the front axle to CR of the rear axle. (let's assume it is 1040mm)
2) the total moment arm of the kart is 158 kg*1040mm = 164320kgmm
You wish to move 0.7% forward= 0.7/100 * 164320=1150.24
The easiest thing to move is the 15kg of lead so it needs to move 1150.24/15=76.6 millimetres (about 3 inches)
If you cannot move the lead forward, then you will need to move the seat. Add your weight (and the lead if it is attached to the seat) (eg 45kg +15kg=60kg) divide by the weight of the lead (60/15)= 4, move the seat 76.6/4 = 19 mm.
As for your side to side balance, 2kg difference is just your head moving not worth bothering about. Your head, in a helmet weighs about 7kg. Move it 35mm (1.5 inches) Or, move the 15kg of lead 17 millimetres to the left
HTH
So
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Weight Distribution and Seat position by 'kartster' (12 Apr 2012 @ 0:28)
