MaxLTV

Just learned that my racing series switched the spec tire from Hankook Medium to Pirelli Medium slicks. If anyone has experience with both, how much of a setup change should I plan for? It's a last-moment change, for me at least, so getting time to work on setup is tough. Or is it mostly the same?

Frank 993 C4S

The Pirelli has much much softer sidewalls and is easier to warm up and you run it at lower target pressures than the Hankook.

joejenie

You will want more camber for the Pirelli. On our GT4 car, the differnce in Camber is -.75 degrees. in the front and .5 more in the back. Proably won't help the radical much with those numbers though. haha. Funny thing is our race group did the opposite. We changed from Pirelli/Michelin to Hankook. Wanted to save money.

MaxLTV

Pirelli saves us $200 per set. Hankook was taking advantage of the lack of other options. I'll keep in mind increasing negative camber. Hankooks indeed needed surprisingly little.

Oddjob

For those that have run them, are you finding different target hot pressures between Hankooks and Mich/Pirelli? Thought they are all roughly 30 psi?

zedcat

Pirelli recommends 29 psi hot for DHF and 20.3 cold, Hankook recommends 30-32 psi hot for F200 and 22 psi cold, with 19psi the minimum safe pressure.

ProCoach

Fellows, I love you, but realistically, different tire construction, sidewall stiffness and compounds require different setups. More than just camber and pressures.

It may be ok and in the ballpark for driving in a comfortable range, but handling balance, ride height, even gearing and response to aero load can differ between tires near and at the limit.

bwright888

Are you talking for the radical? If so...

It's been a while since I've run the pirelli, so can't remember the setup changes. But... The tyres are quite different in longevity and feel, I found that the Pirelli was super grippy within the first couple of heat cycles and became sticky quickly, but the downside they drop off fast compared to the Hankook. The Pirelli also has a different feel than the Hankook when you load it up in the high-speed corners, once it's warm it feels like you can lean on it harder than the Hankook. The Hankook seems to handle longer runs (30+ mins) and more heat cycles without a large drop off in grip.

The Hankook is the overall better tyre for longer runs, the Pirelli is probably the better tyre for a sprint race

Veloce Raptor

Depending on the weight of the car, and driving style, Pirelli 28-29 hot, 19.5-20.5 cold. Hankook 29-30 hot and, as stated, no lower than 19 cold

MaxLTV

Not what I hoped to hear but it's much better to know than be blindsided. I guess I need to get to work.

MaxLTV

Yes, radical. We have a limit of one set per racing weekend - qualifying and 3 races, with the last race being 35-40 mins - so it sounds like tire management is going to become a factor. It could make things more interesting. But if racing scrubs will not be good for practice, it will quickly cancel out the savings.

ProCoach

it’ll pay off.

MaxLTV

Just wanted to report back on Pirelli slicks. I spent two days working on a setup for them, and I'm so damn proud that I was able to get to a competitive setup on my own! I found the car reset to factory defaults because the crew needed to replace some major parts of the suspension. So I started from zero - factory set up is no good at all. Long story short, in two days got the car down 6.5 seconds to within 0.5s of pole on a 2-minute lap, and it felt like there was more in it, but I just could not get enough confidence after almost a year away from driving and a major crash due to a mechanical issue. Don't mean to brag, but I felt so proud of it - last year I had to hire a pro after chasing my tail for weeks.

But back to tires - it looks like the construction of our tire is different from what GT cars have. The sidewalls a super stiff, stiffer than Hankooks. The crew had to warm up the tires to mount them.

Much of the other suggestions were spot on. The tires needed ~1.5psi less (23 hot) and much more camber. Curiously, they handle heat better than hankooks but take MUCH longer to warm up. They also lightly cracked when warmed up aggressively. I guess they are designed to be used with tire warmers or in a very hot climate. We ended up doing two warmup laps instead of one to get them working, and still in all 3 races a handful of drivers understeered off the track in first lap. It will take some work to figure out how to get the most out of them. So far they are good once they warm up, and don't fall off even after 40 mins, but they warm up oddly - first rears come on, but front is dead because it takes much longer to warm up with these tires, so strong understeer. Then it's great and balanced for a few laps, and then understeer again, but slight, and it stabilizes there until the end. Hankooks were more balanced, only going into oversteer at the end of longer races.

It's also very hard to get them into the working temperature range. I had to overdrive the car on purpose to get them to grip. The weather is still chilly, so this will be less of an issue in summer, but I'd love to be able to get fronts to warm up faster. More tow out? Block the front brake duckts? Or something else?

Another issue is that they accumulate used up rubber in the middle of the tire, and then in high-G corners shed it, making the car slightly hop sideways. It feels unsettling but does not seem to negatively affect the grip much if at all. But some drivers absolutely hated it. They also flatspot easier. But Hankooks were almost road-tire good with not flatspotting.

We'll report back to Pirelli about cracking during warm up and rubber accumulation. But otherwise these tires seem pretty good for our application, just a little more high-maintenance.

I'm still happy as a clam that I was able to get to a competitive setup by myself.

CRex

Very different. If you want, DM me and we can take the conversation offline rather than turning this thread into a geek fest.

I just ran 700km on DHFs at Spa last Weds and then raced C53s at the 12H Creventic race same track for the weekend. They're chalk and cheese--cannot be more different.

Let's find a way to help you efficiently. DM on IG@piekeeper

Oddjob

Having run hankooks and struggled with feel and performance compared to Michelin & Pirelli, I don't mind seeing at least some of the geek fest conversation posted here.

Thanks for any quick insights.