just put new dunlop direzza's on, there were some on this forum that liked the tire so got the 245/40 F and 265 /35 Rear (18's) which is only 1 size up. my C63 is an 09 with P30 performance package and had these are replacing the stock P zero's. i dont do track but love to have some fun on the road with my beast , hey thats why i bought it. with the stock P zero's i always thought that this car handles really well, very responsive and tight and coming from a series of M3's that says something . Discount tires put them on 2 days ago with 41 F and 45 R pressure and my initial reaction was that these tires are great, and they are for regular driving i suppose but once you take it out on the freeway at 60mls/hr PLUS i have to say i am very disappointed. any steering input (read movement left or right) i feel like i am at the of a wheel boat. it lags and makes me very uncomfortable and unsafe. with the P zero's i have always felt i could do anything with this car and now i am scared because it feels like with the slightest movement on the freeway the rear of the car is about to break out. i dont have a problem with that, i did it at lower speeds in corners with the P zero's and every movement of the steering wheel i could feel the car respond and was very easy to read. these DUNLOPS , sorry folks but i dont like them. I wish i had ordered an other set of Pzero's . ANY thoughts or suggestions?? are they too new? will a tire pressure adjustment help?

thanks for any input you may have.

Hard to match the Pzero. Most switch out because they want more than 4K miles out of a tire. But the Pzero is really the best tire for the C63.

I just got a set of Pilot Sports though and they feel really good.. They even hook better than my Nitto NT50's.

try 39 cold psi front and back.

45 pounds is way over inflated, the rears will be rock hard and the contact patch will be smaller. Also the compound in these tires likes heat much like a true R compound tire. Once you get the pressures straightened out I will be surprised if you don't feel they are way superior to the PZeros. They dance for me and proved a worthy track tire until I moved on to race specific tires.

I had a set of Z1 stars, grip is very good,they like some temperature, they work better than P-zeros on track and cheap too, steering response BS RE-11 is still better

i am surprised you dont find any difference, i ran 245 and 275 starspec after my stock Pzero ran out and i felt a major improvement in grip. I also saw a consistent 2 second decrease in my laptimes on a 1 min 20 sec track

Tire pressure is too high.

PS or PS2?

PS2's

thanks all for the responses , looks like i am going play with the tire pressure and see if i can get some improvement.

any luck..? btw boost_gomez you have my dream garage I think....

i dropped the pressure to 40 and must say that is a huge improvement. i have not driven it above 80mls/hr yet and have not really pushed it but my first reaction is that you all were right, the pressure was wayy too high. response is much better, almost like a entirely different tire.hopefully i get a chance to tear it up in the weekend to find out how they handle under extreme conditions but i am a much happier camper now!
thanks guys!

I have 45psi on Nitto NT05. Is it too high?

45 is for full load in the car of 4 passengers and luggage.

I would try 39F / 41R.

i am not as knowledgable as some of the other members but most seem to agree that +/-40 is the way to go. 45 in my case for the dunlop star spec was definitely too high, the guys at discount tires were apparently not aware of what the C63 needs. not all tires are equal though....

easiest way is the ol shoe polish trick. take white shoe polish and put a stripe starting about an inch in out to the edge of the sidewall. drive in a circle at about 30-35 mph. left and right. youre gonna need a pretty big parking lot to do this. keep lowering the pressures until you rub the shoe polish off to the edge of the sidewall. record all the pressures then subtract 3 or 4 psi to come up with your cold pressures. since thats around what you are gonna gain when the tires warm up. try to be smooth when doing the circle and keep the car in as a steady state as possible. usually you add a pound or two back to the rear but the c63 has no problems rotating hehe.

Thanks guys. I'll try that.