Understanding ET on Wheels?

[David Hype]

Hi guys, can someone please give me a really simple explaination on the ET measurement on a wheel?

What confuses the st out of me is that the overall dimensions are in inches say 8J x 18 (8" width by 18" diameter) but why do we suddenly switch to metric for the ET (say ET 50, is this simply 50mm)

So for example, is the difference between say ET 50 and ET 63 simply 13mm?

Someone please explain, my brain hurts.

[Magic919]

You could Google it.

It's the distance from the mounting face of the wheel to the centreline. If you coud fit a 13mm spacer to that ET63 wheel, you'd get ET50, for example.

Imagine unbolting the wheel and moving it out towards the wheel arch a few mil. That's what an offset change can do. Or the wheel moves further inboard, depending on the change of offset.

[6C4GTS]

Have a play with this - I find it invaluable for wheel mods!

http://www.1010tires.com/wheeloffsetcalculator.asp

[David Hype]

Hi Barry, brilliant mate thanks so much!

[Orangecurry]

Why are tyres measured/sold in inches, millimetres, and a percentage?

I like tyre-bibles explanations

http://www.carbibles.com/tyre_bible_pg4.html

[David Hype]

OC, even better mate thanks.

So why is it so confusing? Your link is cool too, but the info on both websites is totally contradictory.

If I put in the same question to each site I get a different outcome... How come?

[ChrisW.]

Also --- think of ET as inset rather than offset.

So you can use a spacer on a wheel that has too high an inset, but you cannot do anything with a wheel that has to low an inset --- because it could already be touching the arch

[Orangecurry]

what question? Difference between ET50 and ET63 is 13mm

Here's one I prepared earlier - two wheels identical apart from offset.



Now look - offset very different to suit different applications.

Wheel sticks out further here



than here

[David Hype]

OK, simples

[monthefish]

Orangecurry said:

what question? Difference between ET50 and ET63 is 13mm

Here's one I prepared earlier - two wheels identical apart from offset.



Now look - offset very different to suit different applications.

Wheel sticks out further here



than here

[nsa]

If you think that deep dish wheels have low or negative offsets, you should be able to remember how the ET works.



Most modern wheels have higher offsets. The hubs sit flush or near the outer wheel rim.