New Wheel Sizing Help Please
 

New to P Cars...and doing custom wheels in general...I just bought Zulu's/John's '01 996 Turbo.

I am going to a set of 18" wheels - 18x8.5 front and 18x11 rear - and need help with recommended offsets please!

The car is currently slammed on coil overs and is currently running some 19" BBS F1 wheels, that came off a 997. They have 245/35/19 fronts and 315/25/19 rear tires and are both pushed out with what look to be 1/2" spacers and longer lug bolts. No rubbing what-so-ever.

My wheel/tire considerations are:

• 18 x 8.5 w/ 225 or 235-245/40/18
• 18 x 11 w/ 295 or 315/30/18

(I'd prefer to run the wider tire configuration if possible but am concerned about clearance/rubbing)

As I understand, stock rim sizes and offsets are:

• 18 x 8 50mm
• 18 x 11 45mm

I have a 996TT buddy with factory suspension that suggested I go to the same offsets he is running (to push them out a bit):

• 18 x 8.5 et45
• 18 x 11 et38

My wheel mfg however just came back today with these recommendations:

• 18 x 8.5 et47
• 18 x 11 et42

"This will be 3mm more aggressive than the oem fitment based on the information we have. Now keep in mind that's on OEM ride height. You're lowered on coil overs and we can't estimate the amount of camber you may have. If you want we can make them right in the middle of the offsets your friend is running and with what we know, should work without any issues."

I would prefer to run:

• 18 x 8.5 w/235 or 245/40/18
• 18 x 11 w/315/30/18

Can anyone please help a newbie understand what rim offsets and tire sizes I should consider going with?

Other questions please:
I'll be changing my lug bolts - OEM lugs are ball seat but the rim maker normally makes the wheels conical seat. They can make ball seat if I want. What do you suggest I go with?

Thank you for any help you can provide. Much appreciated.

Attachment 1220408

No input?

You may get more feedback if you post this in the 996 forum that gets much more traffic.

I would suggest that you measure the offset of your current 19" rims and use that as a starting point. The overall diameter of the 18" rim + tire is usually about 1" less than 19's so you will also have more fender liner clearance when you turn the wheels.

As far as the lug bolts, I would go with the ball seat for the rims too. If that's not possible or available, I would change to studs and conical lug nuts.

Good luck!

MGR