# Offset (Et)



## Eric @ TIRE RACK (Jan 27, 2000)

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*WHEEL OFFSET (ET)*

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*Positive ET*
The hub mounting surface is toward the front or wheel side of the wheel. Positive off-
set wheels are generally found on front wheel drive cars and newer rear drive cars.
As long as you purchase wheels from a reputable company, such as  you
are assured that the wheels selected are specifically engineered for your particular
vehicle. One of those design parameters, offset, (ET), is not normally an issue of
concern or worry for you. For practical purposes and the majority of applications, Et
is all about the wheel's need to fit in the wheel well without rubbing on anything.
On the inside we have suspension components or other stationary components of the
vehicle such as the inner fender liner. On the outside, the wheel needs to be positioned
within the wheel well and not stick out beyond the fender lip. As well, the wheel needs
to be designed so that there is no contact with anything when turning, full lock. Brake
caliper clearances have to be taken into account and are during the design of a wheel.
My typical analogy is your vehicle's alignment specs: VAG gives Alignment specs
measured + or - so many thousandths of an inch, allowing for a range to work
within for a given vehicle. Not too many will argue with their vehicle mechanic
that the alignment needs to be a certain spec, they just let the mechanic set it,
using his professional discretion (Exception: Race set-up).
Including VAG, MBZ/AMG, i.e., any and all German Vehicle manufacturers, etc.
(actually I don't think any vehicle manufacturer on the Planet), make their own
wheels. They farm such duties out to existing Wheel manufacturers. Enter BBS,
& Borbet, both German wheel manufacturers, or O.Z. Italy, who make the OEM
wheel for the R32. Believe me, these folks know what they're doing, paying
pretty good money to their in house design engineers. Don't think that the
TUV is going to allow a wheel manufacturer (German or otherwise), to put
wheels on the market that are not safe and specifically designed and
engineered for the vehicle(s) that they say they are for.
Here's another way to look at it. Overall, the aftermarket will almost always make what-
ever it is that they are making, design and engineer a product acceptable in the market
place, but whatever it is that goes to market will be "more aggressive / tweaked" if you
will. H & R isn't going to bother making a spring kit that's just like the OEM springs. No,
they gots to provide an improvement. APR isn't going to make a chip that doesn't improve
engine performance. You wouldn't upgrade your 1.8t with another KO3 Turbo just like the
one that is already bolted on, naw you'll go for a K04 right? Right. If they're going to
build it, then you'd better buy it. And you won't buy it if it doesn't improve performance.
A more desirable product, a bigger better performing product is what we're all after.
Wheel manufacturers know that the consumer is buying the wheels because they
want to personalize their car, make it look unique. So when they bolt 'em on and
the vehicle handles a little bit better, ...well that's a good thing too, right?
Yes at some point some dimension/measurement is too much. Here's a real simple
hands on nuts & bolts thing to do. Go pick up a metric ruler and measure 5mm. Thats
0.1968503 of an inch. Look at that dimension, it's less than the thickness of a pencil.
I'm not at all trying to be smart, but I seriously doubt that that small of a measure-
ment is likely to somehow hurt or be unsafe for your vehicle. It's ok to trust highly
skilled wheel design engineers, The Tire Rack and even me.
Bottom line, ET is + or - so much, i.e. there is a range that works on your vehicle not
any one particular ET. Et35 is a good starting point. As well, you can look at the vehicle
specific and wheel specific posts that I've made that are listed in FAQ - Wheel Tech, as
well as the Upgrade Garage to see acceptable Et's for a given vehicle.
Hub Centric Rings
Lug Hardware
Bolt Pattern
Tools

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As Moderator of The Wheel & Tire Forum, I ask
that if you require my technical input, please
include my name, *Eric* as the 1st word in your
post/question Topic Title.
If at all possible, Please refrain from Emailing Me.


_Modified by Eric @ TIRE RACK at 6:29 PM 3-25-2005_


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