Changing alloys - need some spec help
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Junior Member
Joined: May 2016
Posts: 54
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BMW E46
Changing alloys - need some spec help
Hi - my head's going round the bend trying to understand what offset I will need when changing alloys.
Car: W204 C63 Saloon
OEM Wheels - alloy size on what I have now:
Front Wheels: 8Jx19 ET45
Rear Wheels: 9Jx19 ET54
My tires are 255/35 ZR 19 & 235 35 ZR 19 and plan to keep them.
I want to change them to W205 19"C Edition 1 alloys - replica versions.
They are 8.5J front and 9.5J rears.
What ET offset range on the front and rears will work? Does it need to be ET45 and ET54? Or can it be varied a little, if so by how much?
Car: W204 C63 Saloon
OEM Wheels - alloy size on what I have now:
Front Wheels: 8Jx19 ET45
Rear Wheels: 9Jx19 ET54
My tires are 255/35 ZR 19 & 235 35 ZR 19 and plan to keep them.
I want to change them to W205 19"C Edition 1 alloys - replica versions.
They are 8.5J front and 9.5J rears.
What ET offset range on the front and rears will work? Does it need to be ET45 and ET54? Or can it be varied a little, if so by how much?
Last edited by wsc; Sep 12, 2020 at 07:39 PM.
Super Member
Joined: Mar 2019
Posts: 522
Likes: 129
From: Bondi Beach , Australia
2013 W204 C63 AMG P31 Estate wagon
W205 C63s Edition 1 wheels are same dimensions with ET38F & ET56R and fit our W204 with your tires.
The fronts will be nice and flush and the rears similar to what you have now
I was looking at a genuine set of Forged Edition 1's yesterday at a local tire place who sells lots of pre owned Merc wheels.
I told the guy I was planning to fit 245 fronts instead of 235 and he said don't as they have tried it on customers cars and the 245 rubbed.
He also said 265's fit the rear and look better.
The fronts will be nice and flush and the rears similar to what you have now
I was looking at a genuine set of Forged Edition 1's yesterday at a local tire place who sells lots of pre owned Merc wheels.
I told the guy I was planning to fit 245 fronts instead of 235 and he said don't as they have tried it on customers cars and the 245 rubbed.
He also said 265's fit the rear and look better.
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,308
Likes: 80
From: Houston - Clear Lake
C63 coupe, Z3M Roadster garage queen
Your OEM wheels are 8" ET45 up front and 9" ET54 in back.Width and offset are the same for 18" and 19" wheels.
Ideally, you'd want to keep your wheel centerline in the same place in order to maintain suspension geometry. That'd mean reducing the offset by about 12mm for every extra inch of wheel width that you add. Reality is that your rims will hit the shocks if you go that far.
I'm running 18" W212 (E63) wheels that are 9" ET37 up front and 9.5" ET52 in back, on stock springs.
Tires were initially 255 and 275, and I had an occasional rub on the rear wheelwell liner. I'm now on 245 and 265 tires with no rub at all.
Ideally, you'd want to keep your wheel centerline in the same place in order to maintain suspension geometry. That'd mean reducing the offset by about 12mm for every extra inch of wheel width that you add. Reality is that your rims will hit the shocks if you go that far.
I'm running 18" W212 (E63) wheels that are 9" ET37 up front and 9.5" ET52 in back, on stock springs.
Tires were initially 255 and 275, and I had an occasional rub on the rear wheelwell liner. I'm now on 245 and 265 tires with no rub at all.
