Hi, has anyone fitter 315 tires to a 488? thinking of 315/30R20 on stock rims. cheers LB
I haven't but they probably would work. They 315/30/20 vs 305/30/20 are .3" taller and .3" wider. Width is no issue but since they are taller and that puts the front to rear overall diameter greater than stock you could run into ABS and tractional control issues. Also taller rear = slower acceleration. Nothing you will notice probably putting around on the street though. Stock overall diameter front to rear is 26.8" (fronts) 27.2" (rears) = .4" diameter difference between front and rear. This is how the cars ECU was tuned for...for ABS and Traction Control. You can deviate a small amount with out the computer thinking a tire is slipping/losing traction. Going to a 315/30/20 raises the overall diameter by .3" making the front to rear difference .7" difference instead of the stock .4" difference. However I do think you will OK because people use 20/21 sizes with rears being 325/25/21 and that add's only .2" to the rear diameter and some use 355/25/21 and that add's .6" diameter to the rear to front ratio so you going to 315/30/20 rears falls right between this.
The problem here is not the difference with OEM tires. The problem can come out of the difference with the front ones. You have to stick as much as possible to the OEM ratio rear/front otherwise you will have Ediff problems. If you want wider rears you need to increase front as well 265/30R20 front and 325/30R20 rear, that’s what you need, IMO.
265/30R20 front and 325/30R20 rear, that’s what you need, IMO.[/QUOTE] These are the sizes I would love. But I don't think the stock rims can fit these? Ferrari service won't answer me on there opinion.
These are the sizes I would love. But I don't think the stock rims can fit these? Ferrari service won't answer me on there opinion.[/QUOTE] For your 265/30/20 325/30/20….26.3/ 27.7 is the front and rear overall diameter… that’s a 1.4” difference stock is is 26.8/27.2 with a .4” difference. The overall diameter ratio between the 265/325 -30-20 will not work and cause abs and traction control issues. The ECU will think a tire is slipping and cause traction control to come on when accelerating and same type of thing when braking cause ABS issues.
For you all going with a different tire size than stock…you must stay close to the .4” front to rear overall tire diameter. I haven’t played with this on Ferrari but have with Porsche and Vette and have seen 1st hand the issues with some track friends and a student I had at a track event and not adhering to keeping that ratio difference very close causes issues you do not want
My 992 turbo has 325 instead of 315. Works perfect. I guess that’s the because of the .4 Ferrari answered and said stay at stock size 305, but 315 will work. .4 won’t really make a difference. I think stock size is best
The tire size numbers 315 302 325 are section width… it’s the 2nd number in the tire size that determines the height along with how it ties into width. Following the three digits identifying the tire's Section Width in millimeters is a two-digit number that identifies the tire's profile or aspect ratio. This is the “height” of the sidewall, expressed as a percentage of the section width. The difference between front to rear is .4” stock. Rear is .4” taller than front diameter. You must stay right at around that difference …hope this explains it better.
