Not all Michelin Cup 2 Tires Are Created The Same

They may look the same, smell the same, and be the exact same size; but not all Cup 2 tires are created equal, and for good reason.  Michelin produces off-the-shelf tires as well as custom bespoke tires that are engineered with specific construction, tread design, and compounding for a given car.  Choosing the wrong Cup 2 tire can greatly impact the handling, feel, fitment, and performance of your car in terms of seconds per lap!  Because of this, unknowingly swapping to a wider Cup 2 that has a less aggressive compound can actually make your car slower than using a smaller, stickier Cup 2 that was engineered specifically for your car, so pay attention!

GOAL

This is more of a Public Service Announcement to spread awareness of how much technology goes into developing and engineering tires for some of the world’s best sportscars. This article goes beyond the How to Size and Select Tires for PERFORMANCE article and dives deep into how drastically tires of the same model name can differ based on the needs and the goals of a given car. While all Cup 2s are designed around a certain performance window, the magic really happens when choosing a bespoke tire designed for your specific car, which can take performance and subjective feel to a whole new level. If you are upgrading Ultra High Performance (UHP) tires to Cup 2s, there are a few things to know.  If your car came with Cup 2s from the factory, the bespoke version may be the best option and we are about to learn why.

When walking around track days or Cars & Coffee events I often see cars ranging from Mustangs, Porsches, Corvettes, and even a Ford GT with 1-2 mis-matched Michelin tires that are COMPLETELY wrong for the car.  Unfortunately, you can’t always rely on a tire shop to order the correct tire because there could be 3 or more different options for a given tire size.  As car enthusiasts, it’s our duty to be educated and ensure we put the correct tire on our car and not suffer the consequences of someone else’s mistake.

Michelin Pilot Sport Cup 2 vs Cup 2 tread difference

Believe it or not, but these are two identical size Cup 2 tires. Notice the obvious differences in the physical width, tread depth, and especially the differing tread design.  What you can’t see are the equally if not more extreme differences of the construction of the carcass, the belt design and layup, and the compound.

MY BACKGROUND

Until I was involved in the development of production cars like the Ford GT, GT500, GT350 and GT350R, I never knew how much goes in to the construction and compounding of tires and how each aspect affects steering feel, braking/accelerating/cornering performance, wear, balance of the car, etc…  Let alone how almost every component can be optimized specifically for the suspension geometry, vehicle dynamics, and needs of a given car.

Billy Johnson Ford GT Racing and Development Driver
Billy Johnson – Ford Race & Development Driver – Photo Credit: Ford

In addition to racing the #66 Ford Chip Ganassi Racing Ford GT at LeMans from 2016-2019, I was a development driver on the Ford GT race and street cars (along with Scott Maxwell), as well as the GT350, GT350R, and the new GT500. Having been part of the continuous development of Michelin’s racing slicks and winning on them in the Ford GT to working with many of the same engineers on developing bespoke PSS, PS4S, and Cup 2 tires for road cars, I have seen firsthand that world class engineering and technology is brought to the street in ways that are far more advanced than I ever could have imagined.

DEVELOPING BESPOKE TIRES:

Whether for a race car or a street car, developing bespoke tires goes hand in hand with the development of a car.  Michelin’s involvement in motorsports continually expands their knowledge and ability to engineer a tire for a specific car and translates into making bespoke street tires (like the PS4S and Cup 2) that enable street cars to handle and perform better than they ever could with an off-the-shelf tire.

Race Cars:

Every car has different requirements based on many factors. The Ford GT that I raced at LeMans needed a different tire based on its specific nuances of the center of gravity, suspension geometry, weight, weight distribution, downforce, power, and overall vehicle dynamics which differed from the similar mid-engine layout Ferrari and Porsche, let alone front-engine Corvette, BMW, and Aston Martins.

Ford GT Spa 2018
Photo Credit: Ford – Photographer: Drew Gibson

Tires are also one of the most important things that determine the performance and feel of a car on track, and they are the only part of the system that touches the road.

Ford Performance Technical Center Simulator
Ford Performance Technical Center Simulator – Photo Credit: Ford – Photographer: Wes Duenkel

They are so advanced that modeling their behavior in a digital world for multi-million dollar simulators is one of the most difficult and never-ending challenges for every world-class form of motorsport from Formula 1 to Indycar, LeMans, NASCAR, V8 Supercars, etc…

Before race teams like Ford, Ferrari, and Porsche submit a handful of tire option to the FIA (Federation Internationale de l’Automobile) and are locked in to those tires for the year, teams work closely with Michelin to come up with different compounds and constructions that best suit their individual chassis for a wide range of temperatures, wear, and durability for the various tracks and conditions they will face during the year.  They work to optimize the grip, handling, and performance of each set of tires to give them the best performance possible for all conditions.

Street Cars:

Due to the above differences, along with far more variables and requirements that go into making road going vehicles, Michelin works with car manufacturers early in the development process to assist the team in hitting the goals and performance targets for a new car.

Corvette ZR1
Photo Credit: AlphaLuxe.com – Photographer: Billy Johnson

Michelin does this by custom tailoring tires like the Cup 2 and continually refining the tire as the platform starts to mature into production.  Factors like steering feel, response, wet and dry grip, hydroplaning resistance, wear, and many more can be altered depending on the needs of the car.  Michelin does this for some of the greatest cars on the market like the Ford GT, GT350, GT500, Ferrari Pista, Porsche GT3, GT2RS, Corvette Z06, ZR1, you name it.

Table of Contents:

Page 1 – Intro, My Background, Developing Bespoke Tires
Page 2 – TREAD DESIGN – Tread Depth
Page 3 – TREAD DESIGN – Circumferential Grooves, Outer Shoulder Features & Sipes, Cup 2R
Page 4 – COMPOUNDING – Compound Variation Across Tread & Tread Depth, Cup 2R
Page 5 – CONSTRUCTION – Carcass Profile/Shape, Width, Ribs
Page 6 – CONSTRUCTION – Sidewall Stiffness, Run Flat Tires, Cup 2 Connect
Page 7 – How Tread Design, Compounding, and Construction Come Together
Page 8 – Conclusion

16 comments

  1. So when someone modifies the suspension in any manner away from stock specs (ride height, alignement) can this tire to car relationship be considered to be out the window? The high level of engineering that went into that model-matched tire was meant to be applied to the factory spec model, no?

    1. Yes and no.

      For example, if you replace the super stiff factory carbon wheels on a GT350R, GT500 CFTP, Ford GT, Ferrari Pista with a lightweight (flexible) wheel, you will lose steering feel, grip, response, and will need A LOT more static negative camber. All of these degrade performance and feel from what was originally designed. You can read more about this here:

      https://motoiq.com/tested-carbon-revolution-carbon-fiber-wheels/

      Making the car lighter is a positive all around.

      Lowering the car is a positive but if the car’s balance changes from changing the roll centers, springs/bars/damping, alignment, weight distribution, aero, power, etc…) then the car will obviously not handle the same and will ‘work’ the tires differently. If your new setup or alignment makes the car understeer more, the front tires will wear out faster and a wider front tire could be advantageous.

      Overall, if an OEM bespoke tire is better than a given aftermarket tire (or wider tire of the same model, but a less aggressive compound) in stock form, it will likely continue to be better in most situations on a modified car.

    2. Basically what I end up explaining to my clients a lot is we are setting up your suspension for the tires you are running. If you change the tires the setup will change.

      1. The bane of our lives!

        And it gets worse for older cars: Smaller diameter wheel and tire sizes are becoming rarer and rarer. So a car with a good setup can become a car with no setup as x tire becomes unavailable.

        Then again: I’m only really compaining for my own cars, not the ones of clients!

  2. Preach Big Beautiful sideWalls brother! I don’t need them skinny runflat tires, it’s those meaty black beauties that scrub my contact patch!

    Beautiful article! I’ve seen so many drivers go to what they believe will be a more aggressive tire only to go back to their previous setup because the new tire “just sucks” and they have no idea why.

    Thanks for updating your How to Properly Select Tires article by the way, it’s a great resource, the only thing missing is how to find tires that work with FWD, negative scrub radius cars. The new Type Rs much through their conti SC6s.

  3. Great article….thanks! I have a follow up GT350R question: What would you recommend if running running a square set-up (HPDE use only) in an attempt to keep consumable cost down or is it overall best to run the the 305/315 setup regardless? Also if running the factory tire set-up I’d assume fronts would cord before the rears would heat cycle out…would fresh set of fronts dramatically effect handling if used with rears with plenty of tread/heat cycle left?

    Duane

  4. Loved this article!

    I currently have a 2018 GT350 with PSS.
    When I upgrade the tires, should I get the original bespoke PSS, or would I get better performance if I switch to PS4S?

    1. Luis,

      I’m in the same boat, but my guess would be going to the bespoke Ford Sport Cup 2s on the 2019 generation and later GT350. However, 2019 models did have a change in shocks and sway bars, ABS settings, etc to use the more sticky compound.

      1. The 2019 bespoke Cup 2 has the best wet and dry grip. An off the shelf PS4S has the best hydroplaning resistance for deep water. The 2015-2018 bespoke PSS has similar/marginally better hydro than the newer Cup 2, but it’s not as sticky in the wet or dry than the Cup 2, but sticker than the PS4S.

  5. Absolutely superb article! This is the kind of semi-technical info that all track day enthusiasts need and is hard to find out there, that you very much!

  6. What a fantastic article (so much info I wish it was a video). I’m presently looking for a Cup2 Connect tire I saw that is wider than normal for its spec, but no one at Michelin has been able to help me with it. Keep up the good work sir.

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