Wheel and Tire Size
 

I have a 2004 Boxster S with 205/50 R16" on the fronts and 225/50 R16"s on the rears.
I recently purchased a set of 235/40 R18" (8" wide with offset ET57) for the fronts and
265/40 R18" (10.5" wide with offset ET60). I read in an earlier thread that 11" wide rims will not fit on a Boxster. Will 10.5" fit? If so, what size mm spacers will I need for front and back. I have looked at offset calculators but am not sure of exactly where the tires need to be. I also know I will need brake line clips to keep them away from the tires. If they will not fit, I got deal so I will just turn around and sell them, but I would love to make it work.

10mm spacers will bring you close to stock. If I remember correctly the stock ET's are 52 front and 50 rear. i will have a new video coming out in a few days explaining all this stuff!

I’m wondering how 16” wheels are clearing the brake calipers on an 04S? Everything I read says 17” were the minimum size. Just curious.

Your new wheels seem like they are stock for a 996, which have much bigger rear offsets. I believe the closest 10.5" rears are on the 2004 986 Special Edition those have a 42mm offset. You are likely to need some significant rear spacers. You can go to https://www.willtheyfit.com to help with the math.

Here’s a look at 18x10 60ET and a 25mm spacer, base suspension—seemed to clear. No promises on that, though. I only have 17’s for the front and didn’t even run it around the block set like this as I wanted to see what stock wheels felt and looked like for clearance on super wide spacers (and it was getting dark already). This was last Thursday and I may throw them back on again for a test and will put any relevant feedback here if I do. I tried to hang that beer as a clinometer vs. the wheel well. Actual results may vary, lol.

If anyone’s run this wheel with the 8.5 up front, I’d love to hear your impression. $900 to make the set whole is a little risky, but I’m perhaps willing to give it a shot in a couple months.
Enkei NT03+M
Burly mad lad wheels for such a little car... def outlaw zone.

Thanks fellas. My 04 Boxster was originally a standard. I am the 4th owner. The 3rd uploaded a 3.2L after the original 2.7L IMS failed. Where would I get 24mm spacers. 18mm are the biggest I saw on Pelican parts.

Venum on Amazon, as recommended by another on this site. Stainless bolts is the option I went with. Got one cross threaded—-maybe don’t use the impact wrench, go gently into that dark night ; )
I used 25mm rear, 12 front... not sure if I like that on stock wheels sizes. Someone else might advise...

I've had very good luck with Venum on Amazon. Spacers and bolts are high quality and they ship quickly with FexEd.

Three of my cars; 2x'99s and my '02S, all have stock size 17" wheels (7" front 8.5" rear). I'm using 20mm rear and 15mm front spacers. They give me what I think is a perfect stance. I had 15mm square on one of my '99s and yesterday I pulled the rear off and replaced w/ 20mm. The 20mm just looks a bit better than 15mm in the rear.

I'm having the 18" wheels refinished for another '99 I'm working on. With the wider 9" rear wheel and the front being 7.5", I think I'll start with 15mm spacers on all four corners and see how it looks before I go with 20mm in the rear.

I misspoke regarding the Enkeis being 10.5 diameter... rechecked and they’re 18x10. PM’d you with a bit more but should say here that I didn’t try them on the street because they’re corded Hoosiers and although I wanna play with them, that’s lower on my project list that I wish it was.

RedTele58 was the helpful fella here who got me playing with spacers for a street stance. I’ll pull them off for the next round of AutoX, but 20mm in the rear is pretty dead on for curb appeal. You might refer to his pictures in a search.
I’ll edit my previous post to clean up my mistake.
Linc