It is alarming that there are many misconceptions being actually practised by motorcycle riders. One of the most dangerous act is using slick racing tyres on public roads.
A slick racing tyre (or just slick in short) is a tyre devoid of grooves and is used in professional racing. The lack of grooves provide a continuous and uninterrupted surface (footprint) for the tyre. Also, the tyre's compound does not overheat too quickly along the leading edges of the groove blocks.
However, this type of tyre is factually inappropriate for public road use for several important reasons.
1. Wrong starting temperature
All tyres need some heat to work properly. By the way, the term "heat" in this context is about the tyre's internal heat, NOT heat from the road or weather.
This heat causes the tyre's compound and internal structure (a tyre is not just the rubber) to be more malleable, thus conforming to the irregularities in the road surface. Thus, every tyre has a working temperature range.
Road tyres typically work best from around 30 degrees to the mid-50 degrees Celsius, but the front slick's working temperature is around 100 to 110 degrees, while the rear is 120 degrees. That is a huge difference.
This is why slick tyres are wrapped in tyre warmers and heated to approximately 90 degrees prior to the race start.
Should you use it on the road, it means that you are starting out with a very cold tyre, even if it is a typically hot day in Malaysia (around 35 degrees). Remember, a cold tyre offers no meaningful grip for all aspects such as cornering, acceleration, braking.
Riding like a maniac will not warm the slicks up enough, either, not to mention endangering yourself and others.
2. Unable to maintain the temperature
Building up heat is one thing, maintaining the working temperature is quite another.
Slicks are designed to cool off quickly to avoid overheating. So, let us assume that you are able to build the temperature up to 100 degrees. However, traffic and other variables on the road forces you to slow down and this bleeds off the heat, causing the tyre to lose its grip.
And again, you have to choose to ride like a madman again to warm them back up, which is again irresponsible and dangerous!
3. Slicks cannot handle water
Malaysian weather is very fickle, since we are living in the tropics. It can be hot when we were leaving the house, only to get soaked 20 minutes into the ride.
The grooves in street tyres function as water channels to move water away from the following contact patch for grip. A slick, on the other hand, does not have these grooves so it is prone to aquaplaning. Therefore, the tyre is already too cold to offer any grip plus there is now a film of water between the compound and the road. The result is sliding or full on skidding in short order!
4. Heat cycles
A heat cycle means the act of warming up to working temperature and then cooling back down to ambient temperature - shown by that bluish tint on the surface of the tyre.
Every tyre has a heat cycle, with street tyres are able to last through many more than race tyres. A race tyre may see as little as 8 heat cycles before it becomes useless. 8 cycles is the same as riding just 4 times.
5. Modern street tyres are awesome
The current street tyres have advanced so much that one from five years ago could not match its performance.
There are DOT race tyres, semi-slicks that are legal for road use; sport-touring tyres; half road/trail tyres that offer so much grip on the road that one cannot believe. Using DOT race tyres on the track is quite natural, but even certain sport-touring tyres offer almost as much grip as their more sporty counterparts. Plus, you can ride home on the same tyres after trackday and continue to use them for your daily commute or touring or convoys; with added heat cycles and higher mileage to boot!
As you can see, there are different tools for different jobs. If you do not use a hammer to tighten a screw, you do not want to use a track tyre for the road. There is a reason why race tyres are marked with words like "FOR COMPETITION USE ONLY" or "NOT FOR HIGHWAY USE."
So, save yourself some money and avoid the danger.