Getting To Grips With Tyres
Of all the things you can do to your Lotus, there is one component you can change that makes a huge difference to performance and handling. Those four black rubber donuts sitting at each corner of the car are integral to keeping your car moving and shaking the way you want it to – but there is no such thing as a perfect tyre.
Tyre physics is a huge topic that can span verse and chapter in the overall understanding of driving dynamics – but we’ll boil it down to a few essential components for your easy reading. For the purpose of this, we will look at three different tyres and compare them on both a butt-feel and technical basis.
The first is the Michelin Pilot Sport 3, or rather the Pilot Sport 4 (as the Pilot Sport 3 has gone out of production for sizes 16-inch and up). This tyre is known as one of the best tyres for all-round performance – but not necessarily for all-out performance. It’s arguably the best tyre you can have in the wet and has fairly progressive handling characteristics in the dry that makes the car easy to keep under control.
There are two main reasons the Pilot Sport 4 (PS4) is fantastic in the wet. The first is the compound itself: a mix of silica and functional elastomers improve the tyre’s hydrophobic ability – basically getting rid of the water between the tyre and the road – and that improves traction tremendously. The second is the soft sidewall which helps to keep tyre temperatures within an optimum range through continuous compression and expansion when rolling. Tread design is a consideration for water evacuation, but it is the aforementioned two reasons that are the key to the PS4’s wet grip.
The soft sidewall of the PS4 also helps to improve the progression of the tyre. Sidewalls function similar to springs within a suspension system, so a softer sidewall translates to a more forgiving tyre, in the same way a softer suspension is more forgiving. With the PS3 it was found that the shoulders and sidewalls would wear excessively due to tyre flex, and the PS4 has solved some of this by changing the compounds towards the shoulder to ones that are a little hardier with more grip.
The second tyre we’ll look at is the Yokohama Advan Neova AD08R. This has been a popular tyre for many drivers as it’s regarded as one of the stickiest tyres you can get short of an all-out semi-slick tyre, meaning it won’t spit you off the road if it starts raining, but it can still perform admirably on the track or the road.
The performance of the AD08R comes from multiple ribs and steel sidewall inserts in the tyre construction which reduce tyre deformation and improve steering response in extreme situations. By maintaining the shape of the tyre, the level of grip is also a little more predictable as the contact patch doesn’t shift or flex as much under loading.
The compound itself is also fairly rigid and resistant to wear, but is not so hard as the AD08R is anything but economical. It’s a very competitive tyre with flexible enough usage in a variety of situations, although you wouldn’t expect it to perform as well as a PS4 when the roads starts to get wet.
But even with the AD08R available, there is a tyre that’s been around for the better part of a decade. It’s the AD07, and while it may be regarded as an “older” tyre, the variants with the LTS suffix were specifically designed for Lotus models. TOYCARZ has a few of these in stock for the discerning owner – these tyres are said to have slightly softer sidewalls to compensate for the stiffer Lotus suspension setup, and is OE fitment on a number of Lotus models.
So there you have it. If you’ve made it through this piece you’ll have a little bit more understanding as to what kind of tyre is best for your application. Of course there are plenty of other tyres out there – the Hankook RS4s are said to pick up 3-4 seconds around Sepang compared to the AD08Rs, and for the more extreme among you the Toyo R888R is possibly as high up as you should go. But every driver has a specific preference – whether it’s progressive handling characteristics or all out grip – and you should give each a go yourself before coming to a conclusion.