Hello all
so I’ve just bought myself some 18’ split rims and was just wondering what the correct tyre sizes are as I’ve been reading all different.

the fronts are 8.5j
the rears are 9.5j
ive read up that people put a 235/35/18 or a 245/35/18 on the front and on the rear sits either a 265/40/18 or a 255/40/18

and then also wht do you all prefer the michellan pilots sports or Bridgestone potenza ?
thankyou

 

You will need to post the Rim Offsets, tire sizes vary a bit by the manufacture's tire style.

 

have edited the response

 

front and rear offset are both ET 52

 

With ET52 I doubt you will get anything wider than a 225 in there up front without rubbing [or surgery].

Whether or not a 225 works on a 8.5 inch rim you would need to check- [ tirerack is an excellent resouce for this]

On the rears you should be going for a 265x35x18 [25.4 inch diameter] or a 255x35x18 [25 inch diameter]- your speedo is calibrated for the latter.

 

do u no the profile that I’ll need for the front ?

 

225x40x18

 

Brandon,

For purposes of clarity, if I could put wider rubber on those wheels I most certainly would but the offset kills that prospect. With some maanipulation, frnder rolling, more camber etc you might just squeeze a235 in there but Ivery much doubt it. I know for a fact the 225 will fit with that offset as i had a set of offtakes given to me for some work I did for the local agents and much as they looked really good I did not like the feel of the car with them and sold them to friend who had a 993 C4 and then purchased my custom wheels you see in the avatar. They have the correct front [for wide wheels] offset of 68mm up front and with 9.5 inch rims can run a 265 section. The rears are ET60 and at 10 inches wide typically carry either 285 or 295 rubber.

The front wheels you have are typical of those found generally for Porsches but the 928 is anything but typical.

 

@Brandon Baldwin - A number of years ago I mounted a set of 235s on ET54 rims on my '89 GT, which has rolled fenders from the factory at all four corners and thus ~ 1 cm more clearance to the fenders than other 928s. When I took the car on the track for some exercise that year, one of the fronts would occasionally rub under trail braking. No issues ever with 225s. The original 8" & 9" rims on the '89 GT had an ET60 offset, so while moving OE-sized 225s 6 mm further out works fine on mine, adding another 5 mm by going to a 235 did not. On the rear I am running 255s with the 17mm spacers that came on the car, and they look so close that I am certain that they would rub if the fenders weren't rolled. Hopefully that gives you an idea of the clearances.

As for your tire choices, I'd personally take the Michelin PSS (they have now been superseded by the PS4S) over any other tire. Not sure if they come in the right sizes you need, but I've never had better street tires both in terms of grip and longevity on any of my cars.