07 Jul SEMI SLICK COMPETITION TYRES
Tyre manufacturers produce tyres to suit a wide range of applications, and most of us are familiar with the type of tyre fitted to most road cars. These are generally designed with a very fine tread pattern that is designed to be quiet in operation as well as having a very good ability to pump water out from between the tyre and road surface.
They are also designed to provide good grip on most types of road surface. This means that they are all about compromise, providing, grip, comfort and low noise while still being hard wearing so as to last for many thousands of kilometres. Some of these tyres have slightly more aggressive tread patterns and use a softer rubber compound, providing more dry weather grip, but losing out on performance in the wet. This also means that they will not last as long and will probably create more road noise while driving.
These tyres are usually sold as performance tyres. The next step up from that is the ultra high performance tyre, and here we see even softer compounds, larger tread blocks and are often directional as well. This means that they are designed to rotate in one direction in order to get the high levels of grip required to safely drive at speeds well in excess of 200kph.
Even more road noise and shorter life spans mean that these tyres are usually only considered for high performance cars or for drivers that like to push their car a little harder than the average driver. Another big disadvantage of this type of tyre is that they are prone to aquaplane on wet roads, so that although they give better roadholding grip on dry tarmac, when driving in wet or even dusty condition, extreme care needs to be taken.
If you own a performance car that you like to take for an occasional track day, these are probably the compromise tyre that will give good every day driving life and handle the loads created by extreme driving.
For many classes of motorsport or regular track days, a SEMI SLICK tyre is the best option. These are usually made using a different manufacturing technique using a much softer and therefore stickier rubber compound.
Due to having extremely large tread blocks, and less tread depth, so create a huge amount of tyre noise on the road and may only last less than 1500 kilometres if driven as an everyday tyre on the road. Most of these tyres are legal to drive on the highway, although some may be marked for competition use only.
Semi slick tyres are also prone to “heat cycling”, which means that as they get hot through use and then cool down the compound of the rubber alters and they lose some of their grip performance after as few as 4 or 5 cycles, depending on the grade or tread wear rating.
Tread wear rating in a number that indicates how soft the rubber compound is and the lower the tread wear rating is, the less heat cycles the tyre will take before a drastic drop off in grip. Typical wear rating figures in semi slick tyres are between 60 & 120, although some manufacturers go as high as 180-200.
The very high tread wear tyres are often used in motorsport disciplines like drifting, where the tyre need to break traction easily, but still needs to provided consistent road holding abilities while spinning across the bitumen.
This wheel spin creates extreme tyre temperatures as well so these tyres need to cope with more heat cycles that the track racing tyres experience. Once again because of their tread design, these tyres are very prone to aquaplaning, and really should not be used on wet road surfaces wherever possible.
Due to the production methods, and limited markets, semi slick tyres can often cost 3 to 4 times that of comparable size road tyres. Nangkang tyres have 2 designs of semi slick tyre. Their NS2R has been in production for a while now and is made in a wide range of sizes to suit from 13″ to 18″ wheels.
They make a track version in a 120 wear rate compound and a drift/street version in 180. These tyre provide great grip, well in advance of most street tyres and with a tread design that will provide reasonable wet weather grip too, although I have found them to be very noisy on the road.
Recently Nangkang have released their AR-1 tyre which has a much more aggressive tread pattern, that although legal for road use, would probably see you receive quite a deal of interest from the authorities if you used them on the highway regularly, not to mention the fact that with an 80 wear rate, you would be replacing them very regularly. At this early stage there are only a limited selection of sizes available in 15, 17 & 18 inch but the plans are to have a size similar to the NS2R by the end of 2016.
These tyres provide incredible grip at an extremely competitive price, much lower than equivalent sizes in other brands. Viva Auto repair have stock of the 15″ sizes, and can order all other available sizes as required. Ring and talk to Marque to discuss your best option.