Wheels - Whats the offset??

[kraiye]

Lets say I'm buying 2nd hand rims for my civic and the wheels are comming off another car. I know I need 4x100 stud pattern but what is the offset? I mean, what does 'offset' mean and how do u measure it?
Cheers.

[TEGNO1]

Hi
The offset is the distance from the wheels mounting point to the centreline of the wheel.
Zero offset = mounting point middle of the wheel.
Positive offset = mounting point closer to the inside, (deeper dish).
Negative offset = mounting point closer to outside, (less dish).
I wont get into too much detail but in Honda terms here is an example:
My old wheels were 17 by 7 and plus 40 offset,
I bought some new wheels 17 by 7.5 also plus 40 offset
So if the old distance was 40mm from the centre and the new distance is 40mm from the centre....same that means that the the extra 0.5 inch will tuck in.
If i bought a rim which was 17 by 7 but plus 30 then the wheel will come out by 10mm and plus 50 the wheel will come in by 10mm.
Its where the wheel is centred in your car.
So if you want to by new wheels get your current wheels offset (look for a no. on the back of the wheel with the letters ET on it thats the offset).
Then check your clearances and decide wether you want the wheel to go in or out or stay where it is.
Or if you find another set of wheels you can determine if they will go in or come out compared to you old ones.
Good luck.

[kraiye]

kik ass thnx

2 more questions...

1. can the offset be changed/drilled out if its less than what it needs to be? ( i'm assuming u can use spacers if the offset of the new wheels is greater )

2. how many Guinness should i put down for st. pats day ;):thumbsup:

[TEGNO1]

1. Not something i would prefer to do.
To tuck the tire in you could machine a bit of the wheel (mounting point) if possible), after consulting with someone.
To get the wheel to come out you would need a spacer...probably illegal and might need longer wheel studs.
Honda offsets are usually plus 30 to plus 50 range depending on width.
I would preffer to just bolt in on (find the offset you want)otherwise your better off buying a new set without the money to modify them and headaches.
2. At least 15 the more the better..... i guess,
later.
Oh yeah and if you have any trouble let me know especially if you change offset and width.
Example from 17 by 7 plus 40 to 17 by 8 plus 35 = increase of 25.4mm so the wheel extend in by 20.4mm and out by 5mm from existing wheel.
Example from 17 by 7 plus 40 to 17 by 8 plus 40= increase of 25.4mm so the wheel would extend in by 25.4mm from existing wheel.
Example from 17 by 7 plus 40 to 17 by 8 plus 45 = increase of 25.4mm so the wheel would extend in by 30.4mm from existing wheel.
But if you had the same width and different offset.
Example from 17 by 7 plus 40 to 17 by 7 plus 35 = increase of 0mm so the (whole) wheel will go out by 5mm .
Example from 17 by 7 plus 40 to 17 by 7 plus 45 = increase of 0mm so the (whole) wheel would go in by 5mm from existing wheel.

[kraiye]

good ol wikipedia :thumbsup:
http://en.wikipedia.org/wiki/Offset_%28wheel%29



...

Wheels are usually stamped with their offset using the German prefix "ET", meaning "Einpresstiefe" or, literally, "insertion depth". An example would be "ET45" for a 45mm offset.

To measure a wheel of unknown offset, place it face up on a flat surface. Using a rule, measure the distance from the floor to the hub mounting face. From this figure, subtract HALF the total width of the wheel (or the tyre, if one is fitted). For example, if the measurement is 130mm and the tyre is 195mm wide, the offset of the wheel is 32.5mm. A more accurate result is obtained if a tyre is not fitted.

[TEGNO1]

Yeah thats how you get the numbers but using them correctly is more important, most newer rims will have it on there,
just remember if you go a higher positive the rim goes in and the lower the number the more the rim comes out.

[kraiye]

:thumbsup: cheers

[Limbo]

P.S i think the answer you want is +40, that's what i'm running and there is no rub what so ever. Alot of wheels will also have them printed on the inside of the RIM.

Also spacers are illegal in NSW