Everyone knows that kart balance is important, but what good is it if your kart is perfectly balanced and your tyres are all over the place, it defeats all the time you have put in to setting up your kart balance. There are several things that are affected if your tyres are unbalanced.

The main thing and most notable is vibration, if your wheels are not balanced the kart will vibrate and through this vibration you will loose straight line speed and revs. This is particularly noticeable when road racing however is just as important even if less noticeable when sprint racing.  The front wheels are probably more important than the rear however balancing both front and rear will give you the greatest benefit.

To balance your wheels it is really quite simple. the front wheels can be done on the kart, whereas the rear wheels will need to be put on a bearing hub so they can be balanced. Most good kart shops will have a rear wheel balancer however they are not such a common thing for people to buy so you may need to borrow one or make one.  Making one is very simple using a rear hub, a couple of front wheel bearings and an old stub axle. The theory for balancing the front and rear is the same, the only difference is you will need the rear wheel balancer to do the rear wheels.

Firstly, start with the front. make sure your wheel can spin freely on the stub axle and there is no resistance from the wheel nut being too tight or the bearing being old, worn or clogged up with dirt. Spin the wheel slowly and let it spin until it stops on its own. You will notice that the wheel will probably stop and then roll back the other way until finally stopping. If it does this then it is out of balance. Where the wheel eventually stops you must add a piece of lead wheel weight at the top of the rim. This is directly opposite the heavy part of the wheel which has rolled and stopped at the bottom. The lead wheel weights are available in strips from your local kart shop or tyre and mag wheel shop. Remember to clean the part of the rim first with brake cleaner or something similar before you stick the lead weight on. Normally you would stick it on the inside of the rim where there is a larger flatter area and it will not be seen as easily. Be careful however if you use some kind of data logging or speed sensor on the inside of the rim as the lead weight will probably upset it. In this case you would need to put it on the outside of the rim. After attaching the lead weight spin the wheel again slowly and see where it stops. If it stops at the same place again add more weight and repeat the process until the wheel does not roll back at all. Wherever you put the wheel it should stay in that exact position and not move at all if balanced correctly. All you have to remember is the theory - the heaviest part of the wheel will always roll to the bottom - so make sure the lead goes on the top. You may find you have a couple of pieces of lead in different positions on the rim and this is OK as the wheel may not necessarily be able to be balanced with lead in just one location.

You will probably find that the older the rims are the more out of balance they will be and with tyres it is more important to balance them when they are brand new and fitted to the rims for the first time. However you should always continue to check them throughout their life especially if you remove and refit them to either the same or different rims.

The same technique is used to balance the rear wheels on the rear wheel balancer.  Finally when completed it is also a good idea to add some tape over the lead weights to help keep them in place.  If you have gone to the trouble of balancing your wheels you certainly don't want the weights coming off and ruining all your good work.