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Wheel Offset fitment Info

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A lot of people don't know this... (and I myself just figured it out)



For any individual alloy or steel wheel, ET and Offset both have the same meaning and value. The term ET originates from the German word 'Einpresstiefe' which translates as 'insertion depth'.


A:The distance between the rim's center line and its
mounting surface. From the picture below it should be
obvious why it's important to retain proper offset when
you change rims: tire not centered properly affecting
drivability (negative roll radius changes), bearing load,
rubbing on the struts or wheel arches, etc.

Cross sectional view of a rim:

[IMG]http://i711.photobucket.com/albums/ww117/boomboomskye/wheel_offset_diagram.jpg[/IMG]

Basic rule of thumb:
- Higher offset (ET50 for example), wheels sit closer to car, have chance of hitting brake and suspension components
- Lower offset (ET10 for example), wheels sits further out from car, lots of room for components but may poke past fender or impact fender on dips and bumps

There's more fitment than just offset... If you're running(for example) a 6.5" wide rim with ET 40, it will not clear the same as a 8" wide rim with ET 40..

ET is a hard measurement, not a %age.

For example, how much wheel will overhang towards the body from the mating surface:

6.5"/2 = 3.25" + 1.6"(roughly 40mm) = 4.85"

8"/2 = 4" + 1.6" = 5.6"

and for the section of wheel outwards of the mating surface:

6.5"/2 = 3.25" - 1.6" = 1.65"

8"/2 = 4" - 1.6" = 2.4"

In both cases you have an ET 40 wheel, but the 8" rim will be MUCH closer to the suspension components and body, and it will also poke out more. Just because the offset is the same, doesn't guarantee anything when going wider.
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Posted · Report post

The maths confused me. And i got an A in it at school.

But thanks :)

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Posted · Report post

Very useful when sourcing new wheels.

[url]http://www.carlsalter.com/wheel_fitments.html[/url]

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Posted · Report post

So if i bought wheels that were ET30 i'd need a 5mm spacer yeaaaaaaaaaah?

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[quote name='Ross.' date='12 May 2010 - 06:11 PM' timestamp='1273687900' post='914309']
So if i bought wheels that were ET30 i'd need a 5mm spacer yeaaaaaaaaaah?
[/quote]

if you want to achieve the same look as a wheel with a et of 35 then yes

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Posted · Report post

Ok cool. Cos the minimum ET of a civic is ET35 so if i bought a set of ET30's then i'd need a 5mm spacer,

cheers smiley!

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Posted (edited) · Report post

what you buying now??? your ride looks sweet on the sw9??? whatever there called Edited by Smiley

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My mates got a set of BBS's RM's for sale and there ET33. Am not gonna buy them. But a really do want them.

And cheers, i'll just keep em. But in the future I might get a set, once i've kerbed the SW96's!

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I've found some et32 wheels,
as I'm stupid and rubish at maths with these fit my 1993 del sol?
Will they fit in the arches and not overhang
there 7j wide

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Nah, surely if you had ET30 and added 5mm spacers you would achieve an ET25,

Thought about this alot, if u had an ET 0 and added 5mm spacers it would make more room for compents making the wheel stick out more,

Correct me if im wrong
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Posted (edited) · Report post

[quote name='rob2.2' date='14 May 2010 - 07:09 PM' timestamp='1273860568' post='916371']
I've found some et32 wheels,
as I'm stupid and rubish at maths with these fit my 1993 del sol?
Will they fit in the arches and not overhang
there 7j wide
[/quote]


7j with a 32 offset is fine mate. I have a set of 8"wide wheels with a et10 which i am putting on my eg very soon. (And they only poke a bit, not allot) yours will be good fitting in the arch, snug.

HERE guys use this to calculate the extra poke or tuck youl get from wheels you want to buy, then take a tape measure to your car to get an idea if theyl fit.

[url="http://www.1010tires.com/WheelOffsetCalculator.asp"]Offset Calculator[/url] Edited by Glenno

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[quote name='majicbenji' date='17 May 2010 - 11:37 PM' timestamp='1274135860' post='919596']
Nah, surely if you had ET30 and added 5mm spacers you would achieve an ET25,

Thought about this alot, if u had an ET 0 and added 5mm spacers it would make more room for compents making the wheel stick out more,

Correct me if im wrong
[/quote]


Your right mate, adding spacer (increasing how far out the wheel sits from the body) means a lower offset, not higher

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Posted · Report post

Yep i was wrong. Adding spacer will make it et25. I apologise for my bad info.

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I've used the same website Glenno posted. But there's another which is loads better for you. You can set up what your wheels are at the moment, then set up the wheels you want and compare.

http://www.rimsntires.com/rt_specs.jsp

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Posted · Report post

great info mate, good to know

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[quote name='Gow_face' timestamp='1275611112' post='936012']
I've used the same website Glenno posted. But there's another which is loads better for you. You can set up what your wheels are at the moment, then set up the wheels you want and compare.

http://www.rimsntires.com/rt_specs.jsp
[/quote]


This is pure gold info, thanks for sharing.

Wanted to check what clearance i'd be getting going from 195/15's et50 to 205/16's et55, It went from 2" to 2.2", sound about right to you guys?

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1. Plus Zero
This method utilizes the same wheel diameter as Original Equipment (OE) but incorporates a tire with a larger than OE section width and smaller than OE aspect ratio. For example, replacing an OE 175/70R14 tire (on a 5.5-inch wheel) with a 195/60R14 tire would be a proper Plus Zero fitment. Note that this practice may require a replacement wheel in order to maintain proper rim width for the new tire.
2. Plus One
This method utilizes a one-inch larger diameter wheel in conjunction with a tire of a one-step lower aspect ratio. An example of an appropriate Plus One fitment is to replace an OE 175/70R13 tire (23-inch overall diameter) with a 185/60R14 tire (22.9-inch overall diameter). Note that this method always requires a replacement wheel.
3. Plus Two
This method utilizes a two-inch larger diameter wheel in conjunction with a tire of a two-step lower aspect ratio. An example of an appropriate Plus Two fitment is to replace an OE 175/70R13 tire (23-inch overall diameter) with a 195/50R15 tire (22.8-inch overall diameter).
[url=http://www.cheapeuroparts.com/]vw parts[/url]

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Posted · Report post

i dont understand this :(

so i drew a diagram, is this correct? the higher the off set, the further the wheel sits from the brakes etc?

[img]http://img718.imageshack.us/img718/1475/exmaple.jpg[/img]

i have 9j offset 20 on the rears now, if i was to get offset 30 9j's would that tuck my wheels in more?

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The higher the offset the more in the arch the wheels are
The lower the offset the futher they are from hub e.g. closer to arch or poke out

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Ive ordered some new wheels which are 16s but 8inch wide and et35, funning standard shocks atm and 282 brakes i think will i need spacers are anything else to fit them?

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Posted · Report post

Spacers?! Hell no.

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Posted · Report post

I dunno bro im not too smart on wheel fitment, just thought id get some advise before trying to fit em

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guys i have a 4 door eg (eh9) i want rotas that r 6.5j n they r et40 im guessin they r gonna tuck but i dunno what civics standard offset is so its hard to judge help pleaseee??

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Posted · Report post

6.5j et40 will pretty much match oem honda fitment.

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you can go +5 or -5 off santdard et with out any spascers and no problums

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Posted · Report post

so useful thanks for this topic :D

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