Hey, I’ve noticed that the most popular aftermarket setups are either 20-21 inch or 21-22 inch. Since the OEM spec is: 245/35/20 305/30/20 it seems that running anything bigger than 20’ while keeping the 30 sidewall would increase the overall diameter on both front and rear. I did a bit of math and it looks like running 255/30/21 front 325/25/21 rear gives nearly the same diameter as the OEM setup. This is unlike 21/22 with 255/30/21 335/30/22 on the rear, which is significantly taller on the rear, but not on the front - hence affecting the “relation” of front and rear. Coming from BMW, I would expect the tire to be 335/20/22 (not sure that even exists) to keep the factory diameter. My question is - why is that? Am I missing something?
335/25R22 is the size people use when doing the 21/22 setup. However, there is not a single benefit of doing so from a driving or performance stadpoint. It is purely a cosmetic thing. It makes the car slower and it makes the car understeer. 255/30R21 and 305/30R21 is a better option from a drivers perspective. Sent from my SM-G930F using FerrariChat.com mobile app
Why not 25 on the rear, but 30? With your suggestion, we’re dropping 35 on the front to 30, but upping the wheel size to 21’ At the rear, we’re upping the wheel size but keeping the sidewall, making the diameter larger.
right! Sorry, typo in the thread, but all calculations and assumptions were done with 335/25/22 in mind.
No prob, I know what you meant. Goodyear Eagle F1 Assymetric 5 in 255/30R21 and 305/30R21 would be my choice for a squared 21" setup. The Goodyear in 305 is a much better tyre than the PZero you will be forced to use with a 315. You could also use MPS4S in 255/30R21 and 325/25R21. This configuration will get you fairly close to the OE front to rear diameter bias. This will upset the balance of the car the least. Sent from my SM-G930F using FerrariChat.com mobile app
I have no doubt it affects performance. But how much, I'm not sure. At least in a straight line. My car went verified 60-130 in 6.28 with my 22/21" setup, which is the 2nd fastest 60-130 time I've found for an F8. Brooks from Dragtimes went 6.20 on a prepped dragstrip in his on the stock wheel/tire setup. So, it doesn't seem to impact straight line performance much at all. I'm running neutral camber out back and slightly negative up front, and with that I haven't noticed any understeer either. But, I've only have pushed a bit on on the street, not on a track.
The difference will not be as significant from 60-130 at it will be from 0-60. The faster acceleration will be more dependent on parasitic loss, gear ratio and rolling resistance. However for the the worst part is how it alters the character of the car. Even at moderate speeds during a fun spirited drive, the weight during breaking, and understeer is noticeable. You should try your car with stock wheels and the big wheels back to back, you will notice the difference. It also makes the suspension also has to work harder as there's less give in the tyre. The suspension was never set up for driving on such hard sidewalls, and it makes the car more nervous.
Honestly, having been a drag racer for 35 years, the 0-60 is more dependent on traction. The P Zeros just aren't very sticky, and of course with my larger size wheels, the tire sidewall is shorter (even though the tire is wider) so the car spins pretty badly (which honestly seems to be the case for F8s and Pistas even in stock configuration). That's why 60-130 is a good measurement, as it removes traction from the equation. I am running Novitec springs, so that changes things as well. I do hear what you're saying, and somewhat agree, but I just feel the weight difference is very negligible with regard to performance, while traction is really the biggest issue.
One more thing to add. A good example of the "traction is king" argument is when you compare a F8 to a 992 Turbo S Coupe. The Turbo S weighs almost 300lbs more, makes 70 hp less, yet still hits 0-60 in 2.2-2.4 seconds, with the F8 in the 2.8-3 second range (both on the street). So even with significantly more weight and less power, the traction advantage of the Turbo S makes it much quicker from a dead stop. From a roll, however, the best I ever ran 60-130 in my 992 Turbo S was 7.1, which is far slower than the 6.28 I ran in my F8. So yes, lighter wheels might make a smidge difference, but it's really the traction issues that effect the F8's acceleration at low speeds.
To each their own. I've been circuit racing my whole life, and to me the handling drawbacks are significant. And as you say, the PZero is not very sticky. For me that just adds insult to injury and is just another reason why one should avoid this setup. I'm not interested in drag racing an F8 or Pista, I want the drivers car sensation the car is capable of delivering. Sent from my SM-G930F using FerrariChat.com mobile app
You cannot make a comparison like that. The TTS is severely underrated. It is not a 650 PS car. Just look at the torque figures. The torque number for the TTS is much higher than the F8. I would also be surprised if there was indeed 300 lbs. of weight difference. Porsche has been underrating for years, so to say its 70 PS less, is not possible. I would not be surprised if the TTS turned out to have more power than the F8. Sent from my SM-G930F using FerrariChat.com mobile app
I hear you. I knew you were a road-course guy, which is why I was surprised you brought up 0-60 earlier. I personally don't care about 0-60 in my F8, nor do I plan on drag racing it. For my purposes, the larger wheels have no real impact on performance, nor do they impact my enjoyment, which is really all I was trying to point out. As far as tires go, I'm switching to PS4S, which, based on my experience, is a much better street tire than the P Zero. Thank you for your input.
