By Sidney Sprocket
Let’s start this month by looking at a nice easy way of avoiding probably the most common way of failing to finish a race within the TKM classes – the chain coming off.
It always staggers me the number of people who have this happen because it is such an easy and inexpensive thing to avoid. All you need to do is use sprocket protectors and fit them correctly.
Now a lot of people make fun of the guys doing endurance racing with Prokarts, but it was from there that I first saw the use of sprocket protectors and realised just how effective they are. And in countless hours of racing I never once had a chain come off.
The original protectors I used were plastic and they worked fine. More recently people have been using alloy ones but they have two big downsides. First if they do ride over a kerb and make contact they bend – permanently. That makes them worse than useless. And second, some clubs have banned them because of the damage they do to kerbs.
But there are some great plastic/nylon types around like these pictured which Tal-Ko sell which are perfect for the job. They are accurately machined to a choice of three diameters to suit all normal sprocket sizes and fitted with the right length bolts and washers will provide outstanding service.
They allow you to have the chain nicely free for minimum drag but at the same time prevent it from popping off while under strain. Simple advice – use them, use quality Gold Gold DID chain and forget about chain problems!
Racing in the wet
Now let’s address a subject which crops up from time to time – whether adjustable castor and camber should be allowed on TKM karts. Aside from a small minority the call has always been to avoid them because it can be very fiddly to set up unless you have all the right equipment, and knowledge is vital in order to make use of them effectively.
The latest call to use them comes from a few people struggling to learn the ropes of wet racing within TKM having come from Cadets. The vitally important thing to note here is that a simple change of castor/camber will probably make little or no difference.
In reality castor/camber adjustment and wet tracks don’t automatically go together. You can dial in or out various characteristics with such adjustment but that is spread across any conditions. If you don’t know where you are going then you can dial up a real bag full of problems, wet or dry.
And the basic plain truth is that the grip and speeds round corners relies very largely on tyres. The TKM wet Maxxis tyres have been designed to give long life to keep down people’s costs. That is what everyone says they want. They could be made softer – but then they will wear out quicker. Who wants that?
So since it looks very likely the long standing commitment to simple no castor/camber will remain, let’s have a look at what the key point seems to be for the request to allow it for wet handling.
Making a TKM (or any other higher-powered kart) go round corners in the wet is quite different to driving a low-powered Cadet. Cadets have low weight, little power, a short chassis and most importantly narrow and soft compound wets. So soft that you can easily destroy them in one drying heat.
So for set up, widen the front track as far as you can and narrow the rear as far in as you can go making sure you are legal. Ideally then raise the ride height at the front by moving the spacer washers at top and bottom of the king pin so that all the spacers are at the bottom. Also raise the ride height at the rear (this option not available on early TKM-homologated karts)
Most vitally give the steering a big dose of toe out – up to 15mm in very wet conditions. And if you have time then also raise the driver’s seat maybe an inch or so. The quick guys will already have holes drilled ready for this.
If I only had time for one or two jobs it would be reset tracking and wind on toe-out. You need to be able to do these things ultra quickly and efficiently and always take the gear to the dummy grid for this if it looks even slightly possible to rain.
Tyre pressures and wheels are important too. The wheels need to be narrow – maybe 110mm at the front and 150 mm at the rear. That gives a better shape to cut through water and find maximum grip. On pressures you must experiment. In very wet conditions I have used 40psi to try to generate some heat. In drying conditions, as little as 12psi.
Then it comes to technique. You need to learn to get the kart pointed into a corner. Once it is pointed in you balance the understeer by giving the engine a stab of throttle to get the rear sliding – and from then on you steer the kart through the corner by the amount of spin generated by the rear wheels.
So brake, off the brakes and then flick the front in and then power out with the rear sliding all the way through a bend. It takes a little practice but once you have mastered the technique then you’ll find it makes you a better driver in the wet in any type of kart or car come to that.
Just for the record you will always find that lap times close up dramatically between classes in the wet. The Cadets are still able to lap close to their normal dry times. But the TKMs and other classes will lose a lot more time because of their greater weight and much more powerful engine causing wheel spin etc.
So there you go – splash out and learn your wet weather skills. Once mastered you’ll find it is fun!
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