In Reply to: Re: BBS wheels and tires--help posted by Jon on August 17, 2001 at 22:34:00:
The math is as follows:
width x . aspect ratio(sidewall) x 2 divided by 25.4 plus the rim width.
Example: 195/60 -15
195 x .60 x 2 divided by 25.4 + 15 = 24.21598 tire diameter.
225 x .35 x 2 divided by 25.4 + 18 = 24.200787
This is the closest to stock. The 235 will be to big also the 245. Try the math..
Hope this helps you guys out....
235/40-17s are NOT the same diameter as factory tires.
225/40-17 is close but only made by Nitto. I have the Nitto 555s and they are alright...not the stickiest.
235/40-17 is popular because of a wide selection. You will get some front fender well rubbing with this size but people use it a lot.
Several manufacturers have recently come out with 245/35-17s which are almost the exact same diameter as the stock tires. I would personally try one of these. They have them at Tire Rack and other stored like Discount Tire will usually order whatever. They are the Michelin Pilot SX GT, the Pirelli P7000, and the Continental ContiSport Contact. They are between $109 and $142.
I just got BBS RX 17's from the previous owner of my car, and the tires on it are 215/40. Two of them need to be replaced, so I went to the tire store, and they told me that to match factory size I need 235/40. Does that sound right? I'm itching to put the wheels on and dont know what to do. Options are: buy two of the 215/40, or buy four of the 235/40. Which is the correct size?