Square setup help, I'm so confused!

[Skysurfer]

Hi all,

I think I've done too much reading and completely confused myself on this topic.

I'm trying to understand what I need to to do to get to a square setup on my Z4C.

I have Style 108s, which I understand are ET47 front / ET50 rear, which, if I'm not mistaken, means they will always be staggered.

Does this mean I can only use spacers to achieve the look or can I run the same size tyres on all four corners?

If the latter, what's a good size to aim for and do I still need spacers?

Thanks in advance for your help

 

[B21]

Square refers to the same size, width, profile, construction of your tyres..

Logically it means the rims are the same width and radius.

However the offset will hardly ever be the same between front and rear for many reasons.

 

[Zephyr]

I guess 225-40-18 will strech the rears a bit and will need a 10mm set of spacers to the back. No idea how this will behave with the ABS/DASC though.

 

[Eddie Zedder]

Regardless of tyre sizes -

Square - wheel widths are the same e.g. 7J all round.

Staggered - wheel width (usually) larger on the rear axle e.g. 7J at the front, 8.5J rear.

Wheel width and offset (ET,) will be on the wheel, not the tyre. For J read inches.

 

[Nodzed]

Square refers to the same size, width, profile, construction of your tyres..

Logically it means the rims are the same width and radius.

However the offset will hardly ever be the same between front and rear for many reasons.

Surely a square setup means the rims are the same width, radius and have the same offset (ET) mine certainly do anyway. Not sure sure how you would achieve it with different offsets front to rear.

 

[B21]

Surely a square setup means the rims are the same width, radius and have the same offset (ET) mine certainly do anyway. Not sure sure how you would achieve it with different offsets front to rear.

Usually the offset are the same to ensure simple one wheel fits front or rear..but since front and rear tracks are often different it’s not mandatory to have the same offset to have a ‘square’ set up…often aftermarket front and rear alloys have same width / diameter but different offsets ..usually for brake caliper clearances

 

[Skysurfer]

I'm looking to run the same size tyres front and rear so that I at least have the option of rotating them if needs be.

I just want to ensure that I"m doing it in the safest and most aesthetically pleasing way possible

 

[Zephyr]

I'm looking to run the same size tyres front and rear so that I at least have the option of rotating them if needs be.

I just want to ensure that I"m doing it in the safest and most aesthetically pleasing way possible

The setup I mentioned above is the most suitable. But you will not be able to rotate the wheels, just the tyres. Meaning you will have to swap tyres between front and rear rims
On the other hand handling will be worse and as I said also, no idea if this will pop a warning at the abs/dasc systems.
These wheels are staggered on purpose, the whole suspenaion is setup to work with these uneven sizes.

 

[Eddie Zedder]

Tech Convo: Square vs. Staggered Wheel Setups

apexwheels.com

 

[B21]

Tech Convo: Square vs. Staggered Wheel Setups

apexwheels.com

Good write up…as could be expected from Apex who do square sets ups..some with different offsets..🫡

 

[Nodzed]

Usually the offset are the same to ensure simple one wheel fits front or rear..but since front and rear tracks are often different it’s not mandatory to have the same offset to have a ‘square’ set up…often aftermarket front and rear alloys have same width / diameter but different offsets ..usually for brake caliper clearances

See your reasoning, but that's not a square setup, square setup means you CAN put all 4 wheels on any corner.

 

[B21]

See your reasoning, but that's not a square setup, square setup means you CAN put all 4 wheels on any corner.

I’m not disagreeing with that practicality..however there are square set up that are not front / rear swappable…

As quoted by the alloy wheel manufacturers above…of which I have a set and they offer

A square fitment is one in which all four wheels have the same diameter, width, and offset. This also means all four tires are the same size.
In some rare cases, cars can require different offsets for their front and rear wheels to account for a specific vehicle’s design or brake/suspension geometry where it's not possible to fit the same offset on both the front and the rear of the car, but will still run four wheels with the same width and diameter. This is called a non-rotatable square fitment.