The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Not All Michelin Cup 2 Tires are Created Equal - Behind the Scenes of Making Bespoke Tires

Hey guys,

Check out my article where I dive deep in to tire technology and the effort Michelin puts into making bespoke OEM tires for a specific car model. This is written from my experience as a development driver working on creating bespoke tires for cars like the GT350/R, GT500/CFTP, and Ford GT. These concepts apply across Michelin's product line and the same amount of effort goes into creating tires for performance cars as they do for sedans, trucks, SUVs, transit vans, etc...


The article explains why replacing an OEM tire with a wider tire of the same model (even with thicker tread) will likely hurt performance, feel, be slower on track, and (if driven at the limit), will often NOT last longer. This is aimed specifically at your GT350R guys who want to put wider (non bespoke) Cup 2s on their cars. In short: The car will handle and perform worse, be slower on track , and likely not last longer if you drive them at the limit.

There is far more that goes into making your factory tires than you might ever have expected.


Not All Michelin Cup 2 Tires Are Created The Same - For good reason.

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!

Sport%20Cup%202%20vs%20Cup%202%20tread%20design-X2.jpg

https://motoiq.com/not-all-michelin-cup-2-tires-are-created-the-same/


In the article

-Michelin's development of bespoke tires for race cars and OEM street cars
-What goes into tire TREAD DESIGN: Tread Depth, Circumferential Grooves, Outer Shoulder Features & Sipes
-What goes into tire COMPOUNDING: Compound Variation Across Tread & Tread Depth
-What goes into a tire's CONSTRUCTION: Carcass Profile/Shape, Width, Ribs, Sidewall Stiffness,
-Cup 2R
-Cup 2 Connect
-How Tread Design, Compounding, and Construction Come Together
And much more...


Enjoy!
 

Ludachris

Chris
Staff member
Moderator
1,230
1,257
Exp. Type
HPDE
Exp. Level
5-10 Years
Newcastle, CA
Thanks for sharing @BillyJRacing - feel free to post any future write-ups like that here on TMO :) We're always looking for racers who want to share some of their insights with the community in the form of articles. It helps the site get found in the search engines when the article lives here too.
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Thanks, BillyJ.

I've understood that differences exist among tires that are nominally the same (as far as the tire model name is concerned), even in true street tires where certain car mfrs add their own designations (K, M, N).

I'm looking forward to reading and hopefully learning more.


Norm
 
3,696
3,585
One thing I've noticed about Michelin in IMSA, they offer several compounds in GT (per event) and they are changing compounds depending on the track and time of year for GS. While I applaud their desire to increase the performance of their tires at a particular track, it also adds exponential problems to guys like me who not only have to chase and record tires, laps, wear, pressures and temps both ambient and track, and across the tread, but now I get to look into my crystal ball and pull out those numbers for misc compounds as well. I have to wonder how many tire failures in GS at Daytona were attributable to lack of due diligence and changing tire specifications by the manufacturer. Seems like a bit of over kill for a "spec" tire series, but hey..at least the cars I looked after had no failures. I was either on my game, or blindly lucked out, not sure which.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
5,601
4,135
Exp. Type
W2W Racing
Exp. Level
20+ Years
Blair, Nebraska
This is a great article not only about Michelin, but because it is so true across the tire manufacturers making everything from Slicks, DOT competition tires, to 200 TWR street sleeper donuts. One only has to look to the change in the Yokohama A052 in 2019 to get their 200 TWR tire into the hands of serious Autocrossers ( after their initial tire was rejected by SCCA). Changes in tire compounding can and do change within the same year , at times, but it is one of the reasons serious racers want the tire build dates to match closely. One of the best reasons many have found Tire Rack to be a great place for Competition rubber , the turnover usually ensures similar dated and current rubber.

The best part of this article , to me, is the relationship of tires built for specific cars, as it illustrates what Manufacturers do to help the Automotive Corporations they are working with in designing a tire for a specific car model. This illustrates how much difference there can be within a single tire manufacturer and it really speaks volumes for those of us who preach not to combine two different tire manufacturers on your car. In other words , when two tires from the same manufacturer don't work optimally ( as noted by BillyJ Racing ) , why would you think mixing ones from , say, Yokohama and Bridgestone could actually be beneficial.

Nice post and sure to elicit more responses and just another example of the solid Tech Info often listed on TMO.
 
Last edited:
3,696
3,585
Well if you want to see some widespread cheating on tires, look no further than FIA karting competition, those guys have it down to an art form, It got so bad that the tire manufacturers were stamping different compounds for different factory drivers. finally they made a spec tire rule, then.. when that failed they then required the organizers to have all the tires shipped in early, piled all the tires in parc ferme, out side of their original boxes, marked them, and then made the competitors go in and pick 4 tires randomly. The organizers mounted them, and they never left parc ferme except to go out on the track, then as you crossed the scales, they came off as you left parc ferme. it was literally that bad.
For those of you not familiar FIA kart racing is literally F1 light, including all the politics.
 
3,696
3,585
and it's good to see Billy Johnson on here. I figured he'd make it here sooner or later since he got booted from "Corner Ponies" ..lol
 

Norm Peterson

Corner Barstool Sitter
939
709
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Finally read through all of the pages in sequence. Some things I was already aware of, some I was not.

I wonder how many people caught the link to "How to PROPERLY select and size TIRES for PERFORMANCE", which is another useful article.


Norm
 
22
23
Exp. Type
HPDE
Exp. Level
Under 3 Years
Erlanger, KY
That was a very interesting article, indeed.

I have a 3-day class coming up at Mid-Ohio from April 13-15 which I plan to use my own car. I just placed an order for a set of 11" Apex SM-10 ET52 wheels for all 4 corners which will arrive assembled with spacers,, lug nuts, TPMS, and 305/30/19 cup 2's. That said, the 305/30 cup 2's arriving on the wheels are the 102Y compound, not the 98Y compound which comes on my R up front (the rear 315/30 is a 102Y).

My questions are these:
- Will the 102Y compound have less friction than the 98Y?
- Will I, a novice, notice the difference in friction during the life of these tires this season?
- With ambient temps expected around 60 F as a HIGH (and cooler in the mornings), will I be able to get the tires to good operating temperature quickly enough when we move from the classroom to the track for skills practice sessions?
- Right now rain is 25-35% forecasted, which could improve in a few days, or so I hope. Will these tires be unusable in the lower temps AND a wet course? I understand the Cup 2 tires are supposed to operate well on wet roads WITHOUT standing water, but I have equal concern given the lower temps and wet ground.
- Should I request moving my class to early May considering the items above?

Thank you all for your insight.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
5,601
4,135
Exp. Type
W2W Racing
Exp. Level
20+ Years
Blair, Nebraska
Not trying to be the harbinger of bad news, but if it rains the Cups are not your wet weather friend. This is the situation with the Pirelli Trofeo , the Goodyear F1 Supercar 3 , the Toyo R888R and the BFG Rival S 1.5 to name a few. Most of the decent track tires have caveats about running in the rain and only a few are really fairly solid in wet conditions. The RE 71R was a pretty solid wet runner but it has done a disappearing act from the 200 TWR track/autocross tire competition. I will state , having run Cups in the past that they do take longer to warm up when cool and to be a bit more cautious with them if the weather stays dry but in the 60s. They really work well when it is warm or mega hot in my experience. A Hoosier is killer in cool weather , dynamite in warm , but ultra hot and it becomes a Country between Italy and Turkey ----- Greece , er, Greeceeeeee !

I would not be that worried about the different coding , it is just time to work them up to temp before you get on the loud pedal. If you usually take 1 lap to warm up take 2 or 3 and no biggie as you will likely be out there for 15-20 minute sessions anyway.
 
22
23
Exp. Type
HPDE
Exp. Level
Under 3 Years
Erlanger, KY
Not trying to be the harbinger of bad news, but if it rains the Cups are not your wet weather friend. This is the situation with the Pirelli Trofeo , the Goodyear F1 Supercar 3 , the Toyo R888R and the BFG Rival S 1.5 to name a few. Most of the decent track tires have caveats about running in the rain and only a few are really fairly solid in wet conditions. The RE 71R was a pretty solid wet runner but it has done a disappearing act from the 200 TWR track/autocross tire competition. I will state , having run Cups in the past that they do take longer to warm up when cool and to be a bit more cautious with them if the weather stays dry but in the 60s. They really work well when it is warm or mega hot in my experience. A Hoosier is killer in cool weather , dynamite in warm , but ultra hot and it becomes a Country between Italy and Turkey ----- Greece , er, Greeceeeeee !

I would not be that worried about the different coding , it is just time to work them up to temp before you get on the loud pedal. If you usually take 1 lap to warm up take 2 or 3 and no biggie as you will likely be out there for 15-20 minute sessions anyway.
Thank you for the insight.
I will check the forecast in the coming few days and see about changing the class to early May, if needed. I also have a 2-day session at the FPRS in Charlotte as part of the GT 350 track attack in mid-May which was given with the purchase of the car.
 

Dave_W

Cones - not just for ice cream
384
360
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
This may be an uncommon view, but I think low-grip conditions are good for novices. There are two things you are concentrating on learning as a novice - finding "the line" on course, and what the limits of tire grip "feels" like. Learning the line can be done at pretty much any speed and in any weather. Learning the feel of your tires "breaking away" is a matter of how much grip they have before you "step over the edge." As long as there's no standing water causing hyroplaning (others with Mid-Ohio experience might know about it's drainange), I'd prefer the lower grip of cool temps and a damp surface for a novice to learn tire grip, which would tend to make the loss of grip less "edgy" and give you a bit more "forgiveness" to correct and regain grip. The downside of rain is wet grass in the runoff is pretty much useless at slowing the car. But Mid-Ohio seems to have a good number of gravel traps in those places where folks are likely to go off.

Novice tip of the day - Relax while driving - no "death grip" on the wheel. Having a very tight grip on the wheel actually numbs the nerve endings that you're trying to use to detect the small changes in tire grip coming through the steering wheel.
 
22
23
Exp. Type
HPDE
Exp. Level
Under 3 Years
Erlanger, KY
This may be an uncommon view, but I think low-grip conditions are good for novices. There are two things you are concentrating on learning as a novice - finding "the line" on course, and what the limits of tire grip "feels" like. Learning the line can be done at pretty much any speed and in any weather. Learning the feel of your tires "breaking away" is a matter of how much grip they have before you "step over the edge." As long as there's no standing water causing hyroplaning (others with Mid-Ohio experience might know about it's drainange), I'd prefer the lower grip of cool temps and a damp surface for a novice to learn tire grip, which would tend to make the loss of grip less "edgy" and give you a bit more "forgiveness" to correct and regain grip. The downside of rain is wet grass in the runoff is pretty much useless at slowing the car. But Mid-Ohio seems to have a good number of gravel traps in those places where folks are likely to go off.

Novice tip of the day - Relax while driving - no "death grip" on the wheel. Having a very tight grip on the wheel actually numbs the nerve endings that you're trying to use to detect the small changes in tire grip coming through the steering wheel.
That is an insightful point of view and one I also see some value in. Though I never plan on driving this car in the rain (if it can be avoided), the colder temps requiring cleaner lines and better braking and throttle behavior practice is interesting.

I am reminded of the scene in Days of Thunder, where Robert Duval has Tom Cruise alter his driving behavior, likely because cruise, while fast, was too aggressive a driver. The result of smoother lines and throttle/braking was that cruise was faster and the tires didn’t become ground hamburger as quickly. A similar sentiment was given by @BillyJRacing in the comments section of his article when someone inquired about staggered vs square for rotating the rubber. Basically, if you are doing it right, the wear should be near even. From that I inferred that smooth saves rubber and is still fast.
 

TMSBOSS

Spending my pension on car parts and track fees.
6,238
3,247
Exp. Type
HPDE
Exp. Level
5-10 Years
Illinois
The second session of my very first track day had a wet track. A quick shower before the session watered the track, no puddles. My instructed asked if I wanted to go out saying I would likely learn more about car control on a damp track then on a dry track. I took him at his word and went out. You drive slower off the “line” and you do learn a bunch regarding throttle and brake application.
I would not hire a water truck to do the same but would do it again if the opportunity presented itself.
 
Last edited:
1,001
934
In the V6L
That was a very interesting article, indeed.

I have a 3-day class coming up at Mid-Ohio from April 13-15 which I plan to use my own car. I just placed an order for a set of 11" Apex SM-10 ET52 wheels for all 4 corners which will arrive assembled with spacers,, lug nuts, TPMS, and 305/30/19 cup 2's. That said, the 305/30 cup 2's arriving on the wheels are the 102Y compound, not the 98Y compound which comes on my R up front (the rear 315/30 is a 102Y).

My questions are these:
- Will the 102Y compound have less friction than the 98Y?
- Will I, a novice, notice the difference in friction during the life of these tires this season?
- With ambient temps expected around 60 F as a HIGH (and cooler in the mornings), will I be able to get the tires to good operating temperature quickly enough when we move from the classroom to the track for skills practice sessions?
- Right now rain is 25-35% forecasted, which could improve in a few days, or so I hope. Will these tires be unusable in the lower temps AND a wet course? I understand the Cup 2 tires are supposed to operate well on wet roads WITHOUT standing water, but I have equal concern given the lower temps and wet ground.
- Should I request moving my class to early May considering the items above?

Thank you all for your insight.
I'm a bit late to this thread, but I have some thoughts for you:

- Will the 102Y compound have less friction than the 98Y?
- Will I, a novice, notice the difference in friction during the life of these tires this season?


Answering both, there might be a difference in traction, but you probably won't notice. Just go out and drive what you have, and work at getting good with those tires. For now, don't worry about what might happen with different tires.

- With ambient temps expected around 60 F as a HIGH (and cooler in the mornings), will I be able to get the tires to good operating temperature quickly enough when we move from the classroom to the track for skills practice sessions?

Short answer is "yes", but you have to be careful. I did a track day with MPSC2's last fall where we started at about 40F and it was fine. Take it easy, brake early and be smooth and the tires will gain temps fairly quickly. MPSC2's work surprisingly well in the cold, but don't overdo it. I monitor my tire pressures on the dash display and when they've come up a few pounds, there's enough heat to start to work them a bit.

- Right now rain is 25-35% forecasted, which could improve in a few days, or so I hope. Will these tires be unusable in the lower temps AND a wet course? I understand the Cup 2 tires are supposed to operate well on wet roads WITHOUT standing water, but I have equal concern given the lower temps and wet ground.

Cup 2's will be fine in the rain as well, just take it easy and find the wet line. There are a bunch of YouTube videos on driving in the wet and they're worth watching. Most corners, the wet line is "get out and stay out" - run wide the whole way through the corner and you'll be fine. You can also use "Weather Mode" in the vehicle settings. Doesn't sound manly, but I did a early spring track day last year on a track that hadn't been driven on since the fall, and Weather Mode worked great when I was sliding around on the slimy pavement.

All that said, I had an opportunity to do a track day today. Same weather forecast you were looking at - fair chance of rain, temps 40 to 50F. Now, I wasn't able to go because of a scheduling problem, but the car is ready and it's sitting on a brand new set of MPSS's. They're exactly the right tire for those conditions. You give up a bit of performance if it turns out to be a warm, dry day, but if it rains you've got lots of grip.
 

Dave_W

Cones - not just for ice cream
384
360
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
From that I inferred that smooth saves rubber and is still fast.

One of my mantras for autocross students is "smooth is fast." The only thing keeping your car on track is four little contact patches. If you make them upset by shocking them with sharp inputs (steering, brake, and/or throttle), they generally won't produce as much overall grip as if your inputs are smooth. I've seen national champion drivers take runs that looked slower because they weren't throwing the car around, but ended up being fast-time-of-day. If you watch the old Top Gear, Clarkson and Hammond are always doing huge power slides and generall hooning for the cameras, but when it's time for The Stig to set a lap time he's neat and tidy with no spinning tires (if he can help it).

How do you get to be smooth, you ask? By looking and thinking ahead. Big wavy-hand generalizations - due to human reaction time and tire/chassis dynamics, there's nothing you can do about things that will happen to the car about 1/2 to 1 second in the future. So you need to be thinking/driving at least 1-2 seconds ahead of the car. The further ahead you are looking, the more time you have to plan your inputs to the car, and the smoother you can make those inputs. You want to be proactive while driving, not reactive. I often see novices stare at the apex as they drive by it, then look up and try to locate where they want to track out on exit - and end up jerking the wheel and/or going off course. You actually need to know where the track-out / exit point of a turn is before you start your turn-in, because it determines the size of the turning arc and how much you need to turn the steering wheel. Road courses can be harder than autocross in that respect, as the track-out is sometimes over a crest - so you need to find a marker to help you. When I did the Boss Track Attack, I was using things like signs in the grandstands, billboards, and a clump of tall weeds to "line up" where the track-out should be in space when I was at a particular braking marker for blind turns.

Hands follow the eyes, car follows the hands. Always be looking where you want the car to go.
 
22
23
Exp. Type
HPDE
Exp. Level
Under 3 Years
Erlanger, KY
A true story about these being different tires. All it took was a 98Y (OEM) to a 102Y to change the compound, tread, and profile. The driving class at Mid-Ohio is complete on the 102Y tires. The non-OEM 102Y did perfectly well for my inexperience. I want to run the course on the CF wheels and bespoke rubber once I reach consistent times on this setup to see the difference.20210430_161829.jpg

20210430_161448.jpg

20210430_161456.jpg

20210430_161650.jpg
 

TMO Supporting Vendors

Buy TMO Apparel

Buy TMO Apparel
Top