18x8 ET 57 with 245/40/18 and 18x9 ET 43 with 285/35/18 - will I need spacers?

[LAP1DOUG]

I am using these exact same wheel sizes on my 986S, and mine are Cayman wheels. The ZII's I have mounted on them are:

Front: 255/35-18
Rear: 285/30-18

Mine fit without any spacers at either end, but I normally run about a 7 mm spacer on the front to gain front track width. ECS Tuning have the best spacers by far.

Your results may vary depending on coil overs, camber setting, and even caster setting at the front can effect the front tire potential.

I know, I know, these tires are wider than recommended for these wheels, but it works fine with ZII's which have relatively flexible sidewalls. I believe RS-3's are similar.

IMHO, the 245/40 & 285/35 combo should be good for track days, but the O.D. is too large to be optimum for autocross when you consider the very tall gearing these things have.

Good luck

Originally Posted by steved0x

I have some 18" Porsche wheels inbound for my 2000 Boxster S in the following sizes:

Front: 18x8 ET 57 with 245/40/18 mounted
Back: 18x9 ET 43 with 285/35/18 mounted

According to this site: 944racing

These look like OEM sizes for some of the Boxster 18" wheels as well as some of the Cayman wheels.

With these slightly wider tires, would I need to run some spacers? If so what size? Any recommended vendors?

Thank you!

Steve