What the hell is offset, bolt pattern, etc...

Posted by Magnum

Offset:
https://www.tirerack.com/images/wheels/tech/offset.gif

The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types.

Zero Offset
The hub mounting surface is even with the centerline of the wheel.

Positive
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative
The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

If the offset of the wheel is not correct for the car, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won't work correctly. We have test fitted thousands of different vehicles for proper fitment. Our extensive database allows our sales staff to offer you the perfect fit for your vehicle.

The bolt pattern or bolt circle is the diameter of an imaginary circle formed by the centers of the wheel lugs. Bolt patterns can be 4, 5, 6, or 8 lug holes. A bolt circle of 4x100 would indicate a 4 lug pattern on a circle with a diameter of 100mm.

The diagram indicates the proper measuring methods. 6 lug wheels are measured like the 4 lug wheels.

http://www.tirerack.com/images/wheels/tech/4bolt.gif

The centerbore of a wheel is the size of the machined hole on the back of the wheel that centers the wheel properly on the hub of the car. This hole is machined to exactly match the hub so the wheels are precisely positioned, minimizing the chance of a vibration. With a hubcentric wheel, the lug hardware will not be supporting the weight of the vehicle, all they really do is press the wheel against the hub of the car. Some wheels use high quality, forged centering rings that lock into place in the back of the wheel. This is an acceptable alternative.

Backspacing is the amount of space from the hub mounting surface to the rear bead of the wheel. for example a 7" wide wheel with a +32mm offset will have 120.9mm (4.76") of backspacing and 56.9mm (2.24") of space from the hub to the front bead of the wheel.

So when looking for a 7" wide wheel for your car you will nead a +32mm offset, 66.2mm center bore and a 5x114.3mm (5x4.5") bolt pattern

this offset/backspacing/rimwidth chart is VERY helpful.

http://www.rsracing.com/images/tech-wheeloffset.gif

[span style=\'color:red\']Posted by Magnum[/span]

Offset:


The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types.

Zero Offset
The hub mounting surface is even with the centerline of the wheel.

Positive
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative
The hub mounting surface is toward the back or brake side of the wheels centerline. \"Deep dish\" wheels are typically a negative offset.

If the offset of the wheel is not correct for the car, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won\'t work correctly. We have test fitted thousands of different vehicles for proper fitment. Our extensive database allows our sales staff to offer you the perfect fit for your vehicle.

The bolt pattern or bolt circle is the diameter of an imaginary circle formed by the centers of the wheel lugs. Bolt patterns can be 4, 5, 6, or 8 lug holes. A bolt circle of 4x100 would indicate a 4 lug pattern on a circle with a diameter of 100mm.

The diagram indicates the proper measuring methods. 6 lug wheels are measured like the 4 lug wheels.



The centerbore of a wheel is the size of the machined hole on the back of the wheel that centers the wheel properly on the hub of the car. This hole is machined to exactly match the hub so the wheels are precisely positioned, minimizing the chance of a vibration. With a hubcentric wheel, the lug hardware will not be supporting the weight of the vehicle, all they really do is press the wheel against the hub of the car. Some wheels use high quality, forged centering rings that lock into place in the back of the wheel. This is an acceptable alternative.

Backspacing is the amount of space from the hub mounting surface to the rear bead of the wheel. for example a 7\" wide wheel with a +32mm offset will have 120.9mm (4.76\") of backspacing and 56.9mm (2.24\") of space from the hub to the front bead of the wheel.

So when looking for a 7\" wide wheel for your car you will nead a +32mm offset, 66.2mm center bore and a 5x114.3mm (5x4.5\") bolt pattern

this offset/backspacing/rimwidth chart is VERY helpful.  

OK so I saw some 18X8 but the offset was +38mm. I of course had to try it on first. The back fits but the fronts didn't. The rims were rubbing on my spring.   So I also saw that there was a 88 z31 that had used some 17's from a 350z with out any spacers, now I think to myself, would those 350z rims fit my car too?   17X7.5 at +33mm and 17X8 at +30mm.. help a noob out someone!   This fella is trying to sell some for $200   and I kinda thinking about getting it, but dont know if they'll fit my s12.

doesn't surprise me at ALL with the fronts rubbing, stock clearances aren't all that great.

Unfortunately, I'm not well versed enough with the offset to tell you whether the 17s will fit, but I'm pretty sure they will need a spacer in the front.

Just so you are aware, 17s on an s12 tend to look rather odd.  Depends on the wheel tho, I've seen it pulled off quite nicely.  Got a pic?

I bought a set of 17's and posted a pic of them on here. It wasn't a week before I sold them. 17's + s12 = no way

you just need badass 17's, which no one here has money for

OK..well thanks. I'll try to find out the clip that I had seen before. I will also try to post it up here too.

http://www.youtube.com/watch?v=BWHYpkRJNfI

See if this works!

I also believe those are 03 z33 track 17 inch rims. Now if the S12 is the same set-up as the z31, hopefully it would fit.

they'll fit good, but kind of nasty (the design)

and im pretty sure 350z's came with 18's+
18's are definitely too big

ragethey'll fit good, but kind of nasty (the design)

and im pretty sure 350z's came with 18's+
18's are definitely too big

This is a VERY comprehensive explanation of wheel sizes and choices, including the performance advantages and disadvantages. And it's written by a 510 guy

http://kmhafer.datsun510.com/wheelFAQ.htm

A must read!