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      08-26-2009, 04:03 PM   #23
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Quote:
Originally Posted by TLud View Post
I'm pretty sure he meant the wheel has an offset of +20, with an effective offset of +15 with the 5 mm spacer.
i think you got it backwards
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      08-26-2009, 04:25 PM   #24
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I thought rom3n has a 10" +15 due to the 5mm spacer. He told me he didn't rub when dropped on h&r's. He was running ps2s, I hope RE-11s have a similar shape.
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      08-26-2009, 05:24 PM   #25
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The effective offset goes down when you add a spacer to a positive offset wheel. (equal to width of the spacer)

So a +20 offset becomes +15 offset after a 5mm spacer install.

Spacers push the wheel out towards the outer fender well. This drives the offset number down. (until you hit zero! )
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      08-26-2009, 06:17 PM   #26
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Quote:
Originally Posted by Lemans_Blue_M View Post
The effective offset goes down when you add a spacer to a positive offset wheel. (equal to width of the spacer)

So a +20 offset becomes +15 offset after a 5mm spacer install.

Spacers push the wheel out towards the outer fender well. This drives the offset number down. (until you hit zero! )
this is a little of topic but i am assuming with 3 piece wheels things change a bit depending on the lip size...is this correct?

for example:

20x10 4inch lip offset +20
20x10 3inch lip offset +20
these two would fit completely different...?
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      08-26-2009, 06:29 PM   #27
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The 10" with 4" lip would be +20 while the 3" lip can't be +20 unless it used a 5mm spacer which would make it as flush as the 4"
lip but still carry the 3" lip. This is just an example.
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      08-26-2009, 06:37 PM   #28
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      08-26-2009, 07:11 PM   #29
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Quote:
Originally Posted by MrHarris View Post
The 10" with 4" lip would be +20 while the 3" lip can't be +20 unless it used a 5mm spacer which would make it as flush as the 4"
lip but still carry the 3" lip. This is just an example.
Nope, I think actually the 3" lip and 4" lip can both have the exact offset and both fit exactly the same. Only difference might b that there is more barrel in the 3" lip and less barrel in the 4" lip. I can b wrong tho. Im assuming this is so because If u wanna go with a bbk, u cant have that big of a lip, so in that case u put a smaller lip so there is more "back room" and u can fit the bbk, but u still keep the same offset...

Correct me if im wrong...
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      08-26-2009, 07:23 PM   #30
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i always thought the offset was determined by how far the actual wheel center is from the hub...i hope someone can chime in because i have never fully understood this
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      08-26-2009, 09:08 PM   #31
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offset explained

Quote:
Originally Posted by m34jlp View Post
i always thought the offset was determined by how far the actual wheel center is from the hub...i hope someone can chime in because i have never fully understood this
Correct, from the hub mounting surface to the centerline of the wheel:

http://www.tirerack.com/wheels/tech/...jsp?techid=101
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      08-26-2009, 09:28 PM   #32
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Quote:
Originally Posted by gthirtyfizle View Post
Nope, I think actually the 3" lip and 4" lip can both have the exact offset and both fit exactly the same. Only difference might b that there is more barrel in the 3" lip and less barrel in the 4" lip. I can b wrong tho. Im assuming this is so because If u wanna go with a bbk, u cant have that big of a lip, so in that case u put a smaller lip so there is more "back room" and u can fit the bbk, but u still keep the same offset...

Correct me if im wrong...
You are on the right path.

There are a number of 'tricks' in the aftermarket wheel business. Many of these tricks are not widely publicized by the wheel companies themselves. This often leads to confusion among wheel buyers about certain wheel specifications.

One of the 'tricks' that is often employed is the manipulation of the wheel center/spoke forging or casting.

You can change the angle of the spokes to artificially create a bigger wheel lip. By designing the center to sweep the spokes back (inboard), you can make the wheel lip wider or narrower within a certain wheel width and offset range. The center of the wheel actually sticks out farther than where the end of the spokes meet the outer barrel.

Now you can simply widen the wheel itself. (while lowering the offset value) That will also get you a wider outer lip.

Cars WITHOUT a BBK installed can have bigger wheel lips than cars with a BBK. That's because the larger aftermarket BBK calipers require more outward wheel spoke clearance, and that eats into the same real estate the wheel needs to make huge outer wheel lips possible.



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