Ok so i'm currently talking with the guys at Fifteen52 and they've asked whether an offset of ET35 or ET40 would work on my car. The wheels are 17x8 with a PCD of 4x108

I need to know kinda urgently so i can get the work started and hopefully have the wheels ready for Ford Fair

I had ET40 no problem, wheels came right to the arches, ET35 might be pushing it, not sure

These wheels will look the bollocks mate I seen the picture on Facebook which ones your after wouldn't mind a set myself 1 day

basically standard ST wheels are ET52.5
Lower ET means the wheels are offset further out
so going from ET52.5 to ET40 is 12.5mm further out, so its basically like having 12.5mm spacers each side

You might struggle to have 8" alloys ours are 7 and anything wider normally rubs on full lock and an mot failure

arent Stew's wheels 8" wide?
they are a similar design to the fifteen52s also

stew's wheels are 8 17x8

http://www.kinobestew.blogspot.nl/

my wheels is 17x7 et40. no problem at all. I also has papers from Tüv Austria that there is no problem with et40 if you need it

Like the sound of this little project

Btw that Focus looks awful

Oki, i'm here. Lol. What Stevie said about the standard ST wheels being ET52.5 and an ET40 sitting 12.5mm further out is correct except an 8" wide wheel rather than 7" throws that out a little bit as the wheel itself is 25mm wider. I have 8" x 17" Compomotive's in ET38 and they fit pretty much perfect. Smack bang in line with the arches. You can't have any rear spacers at all on the rear. You have to make sure you have very low profile tyres if you're lowered or you'll rub. I use 225/35/17 on the front and 235/40/17 on the rear. 235/40 is too thick on the rear though and I catch the arches a tiny bit (lowered 35mm on Bilstein B12). I'll be getting 235/35 next time tyres are due but they're not easy to come by and will be £105 a corner for Hankooks and they have to come from mytyres in Germany as I can't find anywhere else that sells them. The only other brand of tyre I can find in that size are Falken FK452's which are absolutely gash. You have to bear this in mind because if you get a damaged tyre and need it replacing quickly you're going to struggle massively.

As I'm kinda sad like that, I have a small spreadsheet to calculate such things as offset, tyre size etc...

Going from the standard 7" wheels with and offset of ET52.5 to 8" wide with an offset of 40:

Inner edge is 0.2mm further in - not worth losing any sleep over.
Outer edge is 25.2mm further out

For comparison, my alloys sit 15.5mm further out than standard, plus I have 12.5mm rear axle spacers, so 28mm in total at the rear:



The only thing to bear in mind is that wider wheels will tramline more, and I've found the wider track makes the steering a bit heavier.

You will need to lower it too if you haven't already, probably on coilovers so it's more than I have (H&R springs only) or it'll look like a monster truck!

Will look the nuts though once it's all together!