Omega Owners Forum

Chat Area => General Car Chat => Topic started by: bigtow on 07 June 2010, 20:08:14

Title: anyone know how to work out wheel et ?
Post by: bigtow on 07 June 2010, 20:08:14
Hi anyone know how to work outr a wheels et . I have some 8j aftermarket alloys but they don't have the et marked on them . I have measured from across the rearmost outer edge of the wheel to the mounting flange and this is 155mm . But what is the et help please ?
Title: Re: anyone know how to work out wheel et ?
Post by: Marks DTM Calib on 07 June 2010, 20:09:49
I seem to recall its the distance you have measured minus half the total alloy width
Title: Re: anyone know how to work out wheel et ?
Post by: RobG on 07 June 2010, 20:12:40
Quote
Hi anyone know how to work outr a wheels et . I have some 8j aftermarket alloys but they don't have the et marked on them . I have measured from across the rearmost outer edge of the wheel to the mounting flange and this is 155mm . But what is the et help please ?
Answered in this thread http://www.omegaowners.com/forum/YaBB.pl?num=1274910418/0
Title: Re: anyone know how to work out wheel et ?
Post by: Marks DTM Calib on 07 June 2010, 20:15:30
Which confirms what I said, thanks  :y
Title: Re: anyone know how to work out wheel et ?
Post by: bigtow on 07 June 2010, 20:15:41
Thanks guys
Title: Re: anyone know how to work out wheel et ?
Post by: bigtow on 07 June 2010, 21:28:23

Agggggggg I hope I have worked it out wrong as I make it that the wheels have a et of 53.  Which is outside of the spec for a omega apart from getting new wheels is there any way to correct this ?  :'(
Title: Re: anyone know how to work out wheel et ?
Post by: hotel21 on 07 June 2010, 22:26:00
Some good info on here, with a comparator as well...

http://www.carbibles.com/tyre_bible_pg4.html
Title: Re: anyone know how to work out wheel et ?
Post by: 2woody on 10 June 2010, 11:47:47
have just read all of that - he's correct in stating the importance of rolling radius - and then goes about adding it up the wrong way.

rolling radius CANNOT be calculated. period. The only way to establish the rolling radius is to put a tyre on the rim and measure how many times it rotates in a mile. This will be different (by up to 10%) from the figure calculated by the method on that page.

tyre manufacturers do publish wheel revs per mile, but they take a bit of getting hold of.
Title: Re: anyone know how to work out wheel et ?
Post by: Andy B on 10 June 2010, 11:51:39
Quote
.......

rolling radius CANNOT be calculated. period. The only way to  ......

Arrrgh! FULL STOP!!!!!!!!! USA call it a bl00dy period! ........ and breathe!  ::) ::) ;)
Title: Re: anyone know how to work out wheel et ?
Post by: 2woody on 10 June 2010, 11:55:54
I kinda wanted it to come across in the US-way, as in "extended silence to emphasise the previous point"