OEM wheel offset

MiguelToril

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Joined
Aug 21, 2021
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Spain
Hello!
I bought my car with the wheels you can see in the pics and I would like to buy new wider tyres and wheels.
I’m estimating how wider the car will be but for that I first want to be sure about the offset of the current wheels.
Is the offset of my current wheels 31.75?? Measured in millimetres?

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Forget you ever heard the term Offset which is a dimension that is more useful for car wheels. For Jeeps and trucks focus on the wheel's backspacing dimension which is how far into the wheelwell the inside edge of the wheel is positioned past where it mounts to the hub.

Factory wheels have either 5.25" or 5.5" of backspacing. How much backspacing you need depends on the tire width. For an 11.5" wide tire, 4.5" of backspacing works fine, for a 12.5" wide tire 3.75 to 4" of backspacing works fine.

The yellow tape measure is measuring the wheel's backspacing. This is how close to the suspension the tire's inside sidewall will be.
wheel backspacing.jpg
 
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Forget you ever heard the term Offset which is a dimension that is more useful for car wheels. For Jeeps and trucks focus on the wheel's backspacing dimension which is how far into the wheelwell the inside edge of the wheel is positioned past where it mounts to the hub.

Factory wheels have either 5.25" or 5.5" of backspacing. How much backspacing you need depends on the tire width. For an 11.5" wide tire, 4.5" of backspacing works fine, for a 12.5" wide tire 3.75 to 4" of backspacing works fine.

The yellow tape measure is measuring the wheel's backspacing. This is how close to the suspension the tire's inside sidewall will be.
View attachment 277944

Thank you for the quick reply!

Are you not concern about the “other” side of the wheel? I mean, how much wider the car is when purchasing new wheels as this will mark how much wider the fenders have to be in order to keep it covered. In my case the tyres wide can’t be wider as the total car wide, including the fenders.
 
Thank you for the quick reply!

Are you not concern about the “other” side of the wheel? I mean, how much wider the car is when purchasing new wheels as this will mark how much wider the fenders have to be in order to keep it covered. In my case the tyres wide can’t be wider as the total car wide, including the fenders.
Yep going with taller/wider tires is where suspension height also becomes important.
 
If you stay with the current wheels, you can look and see how much wider of a tire will fit (both inside and out).
If you want a wider tire than what will fit inside, you will have to offset the wheel to the outside. If the tire then sticks out past your flares, then you will need wider flares.
You probably don't need wider (offset) wheels. You can get taller tires in various widths. And/or, you can add spacers behind the wheels to make more room on the inside.
 
Some more information about what I have and what I am thinking of.

The car comes originally with tires 225/75/15 (in order words US 28x9R15) and with the above mentioned 7J15 wheels.

Additionally to that, the car is already homologated (you know Europe and its endless rules) with tires 265/70/15 (which means 30x10R15). Those tires actually fit in the current wheels, however the touch inside when turning full steer.

So, my intention is to upgrade to 10J15 wheels, as they are for me the more logical wheels for the 30x10R15 tires (would it be better another kind of wheel?). But not only do I have to look at the tyre size, but at the new total with of the car and the wider flares I can still on it.

Any further comment or suggestion on it, will be much appreciated.