Since early 2011 the Michelin Pilot Super Sport has been the king of Max Performance Summer tires. Their innovative design set a high standard by which all other tires in their class are judged. However, Michelin didn’t just settle for being the best, they wanted to build on what they’d done and improve even further on their already advanced design. The result of their years of hard work and testing is the Pilot Sport 4 S (PS4S).
Know Your Mods Episode 16: Michelin Pilot Sport 4 S
Building upon a revolutionary design is always tough. When the Pilot Super Sport came out with its Multi-Compound design it completely changed our perspective on what a tire can be capable of. To take that design further and improve on it takes enormous effort in every step of development. Michelin’s team of engineers and designers went far beyond the call of duty with the Pilot Sport 4 S, improving tire stability, wet grip, dry grip, tread life, and reducing road noise. In short they knocked it out of the park and we’d like to take you on a tour of the PS4S construction so you can see what makes it special.
Michelin Pilot Sport 4 S Treads
Dynamic Response Technology
One of the hallmarks of a good performance tire is its ability to keep its shape under high speed and hard cornering. When you take a corner at high speeds your car has a lot of inertia pushing it towards the outside of the corner and your tires have to work hard to keep you on track. When the tire is being subjected to that much pressure from weight shift and inertia it needs to keep its shape to properly distribute the pressure on the tire. Uneven pressure on the tire will result in a loss of total grip because too much of the pressure is being applied to one area.
You’ve probably seen a diagram promoting proper tire pressure before [pictured below] and the principle is similar. If your tire cannot fight the lateral forces acting upon it the pressure differential will cause one zone of the tire to have more pressure exerted on it. This inefficient use of the contact patch will result in a loss of grip and extra wear in that area of the tire.
Tire Inflation Guide
Along those same lines, when you’re doing speeds of 100+ (hopefully on the track) then centrifugal force is exerting outward pressure on the tire. If the tread of the tire is not properly reinforced then it will warp [pictured below] and cause instability. Michelin’s solution to counteract these problems on the Pilot Super Sport was to add a Twaron band around the tire [pictured below] to preserve the tire’s shape and contours under high speed and hard cornering. Twaron is a brand of synthetic material classified as an Aramid Fiber. Its properties are very similar to Kevlar for those of you more familiar with that brand of Aramid Fiber. The reason Michelin used Twaron in the Super Sport is because for its weight it is five times stronger than steel, making it a lightweight way to add stability.
For the Pilot Sport 4 S Michelin used their own hybrid blend of Aramid and Nylon in the same configuration for even greater stability. The new tire utilizes an ultra-reactive tread pattern in conjunction with this hybrid blend to maximize the adaptability of the tire to road conditions while minimizing warping.
Michelin Pilot Super Sport Twaron Band
Multi-Compound Hybrid Elastomer
The next feature that makes the Pilot Super Sport, and subsequently the Pilot Sport 4 S, an amazing all rounder is that it is not limited to a single compound. Normally when you buy summer tires or all-weather tires you get a tire made of a single specialized compound designed to either work great in hot dry weather or keep you safe in colder rainy weather.
The genius of the multi-compound design is that you get almost the best of both worlds. Obviously a full on track tire will perform better in the dry, but in the Max Summer Performance class the PS4S really is the best of its kind. The way the technology is implemented on the PS4S is that on the inner portion of the tire is the “wet” compound and on the outer portion is the “dry” compound [see below]. This may sound a bit weird but it actually makes a lot of sense when you think about it.
Michelin Pilot Sport 4 S Multi-Compound Zones
To properly explain how the multi-compound benefits this tire we need to quickly cover contact patches and weight shift. The contact patch is what we call the portion of the tire that is actually in contact with the road at a given moment. When you are driving along normally in a straight line you will have very similar contact patches in all four corners, with some variation depending on weight distribution or if you run staggered tire sizes [see below, far left].
In a straight line your tires are tasked with maintaining grip under acceleration and braking forces. Under these forces the weight of your car will shift forwards or backwards and while the corresponding contact patch does increase in size it will retain its overall shape so you’re getting full utilization of both the inner and outer portions of the tread if you’re not running extreme camber [see below, middle left and middle right]. When you take a turn your car’s weight will shift diagonally in the opposite direction of your turn because the inward force of your tires is fighting the inertia of your car. This puts extra load on the outer tires and especially the outside front tire [see below, far right].
Tire Contact Patch Illustration from left to right: Cruising, Acceleration, Braking, Turning
In the example above you see the weight shift of a car lightly accelerating during a slight right turn. See how most of the weight has shifted off the front right tire but there’s pretty even contact among the other three? The faster you go around a corner the more the weight will shift to the outside tires and consequently more of the outer portion of the tire will be utilized [see below, left].
This is where the beauty of the multi-compound design comes in, the faster you turn the more of the PS4S‘s dry compound is utilized, giving you excellent road holding. Michelin also implemented their Variable Contact Patch 3.0 technology [see below, right] which is a specially designed tread pattern built to maintain a consistent contact patch area between turns and straightaways. Keeping a consistent surface area helps to keep pressure evenly distributed and subsequently to improve grip by reducing hotspots and uneven wear.
Tire Contact Patch in hard corner (left) Variable Contact Patch 3.0 technology (right)