Help me understand this wheel offset thing..

[Aquineas]

If I want the wheel to move inwards, is that a lower or higher offset number? Context: my front passenger TSW Amaroo wheel (which is a 2-piece wheel) was defective. The tire wouldn't hold air and finally the wheel became so unstable that I had to put the stock wheel back on it until a replacement was ordered. When I ordered the replacement, I also ordered another front wheel to use as a full-sized spare (and that works, btw). The problem is the guy who ordered the new wheels ordered the wrong offset and the tire rubs on bumps and corners now, and I can't remember what the original offset I'd ordered was.

Thanks!

 

[Crusty Old Shellback]

Higher backspacing moves the wheel out, lower moves it in. backspacing is how far the mounting flange of the wheel is from the inner lip of the rim.

 

[Audio]

The higher the number, the farther inward it will sit. For instance:
Stock offset for the 1G is 39mm. A 20mm offset will push the wheel lip closer to the fender, a 45mm will pull the wheel lip closer to the strut. So if your new wheel is rubbing on the fender, it has too low of an offset.

 

[dareckibmw]

Check this out..... you can manipulate/calculate those numbers and you'll see how offset works.

This is an example of ours 5.0 rear wheel: http://www.willtheyfit.com/index.ph...dth2=10.5&offset2=45&Submit=Calculate#content

 

[xiaphin]

Check this out..... you can manipulate/calculate those numbers and you'll see how offset works.

This is an example of ours 5.0 rear wheel: http://www.willtheyfit.com/index.ph...dth2=10.5&offset2=45&Submit=Calculate#content

Great website. I also like this 3-Piece Wheel Calculator.
http://stu.taylor-net.co.uk/tools/offset

 

[Crusty Old Shellback]

So Offset is the opposite of back spacing?

 

[Nobody]

So Offset is the opposite of back spacing?

No. Offset and Backspace are two different wheel measurements.

Offset is the distance from the center line of the wheel's width, measured in mm, plus or minus.

Backspacing is the measurement from the wheels mount surface to the inboard, or backside, edge of the wheel. More backspace tucks the wheel in, less backspace moves the wheel outward.

I handle sales, customer service, marketing for a steel racing wheel company (Bassett Racing Wheel) and have done this for nearly 20 years. This question is definitely in my wheel house.

 

[Lord Humunculous]

This question is definitely in my wheel house.

 

[Crusty Old Shellback]

No. Offset and Backspace are two different wheel measurements.

Offset is the distance from the center line of the wheel's width, measured in mm, plus or minus.

Backspacing is the measurement from the wheels mount surface to the inboard, or backside, edge of the wheel. More backspace tucks the wheel in, less backspace moves the wheel outward.

I handle sales, customer service, marketing for a steel racing wheel company (Bassett Racing Wheel) and have done this for nearly 20 years. This question is definitely in my wheel house.

HMM?

So if I change the offset , then that would have to change the width of the rim if it's a measurement from the centerline of the wheel. So how do I change the offset without changing the rim width?

I understand backspacing as that's what we've gone by for years on selecting rims, backspacing and width.

neverminid I found this.

Wheel Offset: Distance between wheel mounting surface where bolted to hub of drum and centerline of rim. Determines vehicles “track” or distance between tires on each axle. Keep the wheel offsets as close to original as possible to avoid steering difficulties or wheel bearing fatigue - See more at: http://www.4wheelparts.com/tire-whe...-offset-backspacing.aspx#sthash.8OJmSRAk.dpuf

http://www.4wheelparts.com/tire-wheel-package-guide/wheel-offset-backspacing.aspx

So changing offset and not changing rim width, it will change the backspacing as well. So they basically do the same thing, just measured in different ways.

 

[Aquineas]

Thanks folks for the quick feedback.

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