# 19" x 8.5J and 19" x 9J ... what is the difference ?



## Snake Pliskin (Apr 11, 2006)

Hi Guys,

Can anyone advise what the difference is please between these 2 alloy rim sizes as they both appear to have the same tyres @ 255/35 R19 but just wondered why one is 8.5J and one is 9J.

What does the difference in J size actually represent ?


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## sylvainttrs (Aug 12, 2012)

Probably because with the same ET52, the 9J whell will fit the big brake (TTRS) but not the 8.5J.


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## Hoggy (May 8, 2002)

Hi, J is the type of rim & 8.5 & 9 are the rim width in inches, so 9J is 1/2 an inch wider than 8.5J
Hoggy.


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## Snake Pliskin (Apr 11, 2006)

Hoggy said:


> Hi, J is the type of rim & 8.5 & 9 are the rim width in inches, so 9J is 1/2 an inch wider than 8.5J
> Hoggy.


Thanks that makes sense ... but both sizes fit the same tyre still ?


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## TootRS (Apr 21, 2009)

Snake Pliskin said:


> Hoggy said:
> 
> 
> > Hi, J is the type of rim & 8.5 & 9 are the rim width in inches, so 9J is 1/2 an inch wider than 8.5J
> ...


This is very useful:

http://www.tyres-pneus-online.co.uk/equ ... dvice.html


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## Philplop (Nov 22, 2011)

Yes, they'll take the same size tyre. Manufacturers give out a range of widths that each tyre will fit. A 255/35/19 is ok on a 8.5" to 10" wheel, I think.

The 19" option on Audi A6 C6's were 8.5J et48 with 255/35/19.


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## Snake Pliskin (Apr 11, 2006)

Thanks for the useful info Guys.

It was puzzling me why there was this difference on the alloy rim sizes, but the same tyre would fit.


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## Alexjh (Oct 10, 2012)

sylvainttrs said:


> Probably because with the same ET52, the 9J whell will fit the big brake (TTRS) but not the 8.5J.


I say don't assume the 9j ET52 will always fit on a TTRS.. I got 19" ET 52, 9j speedline wheels and they couldn't clear the front callipers with out spacers.


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## iamnotthestig (Feb 28, 2016)

Old thread but a search function plus.



Philplop said:


> Yes, they'll take the same size tyre. Manufacturers give out a range of widths that each tyre will fit. A 255/35/19 is ok on a 8.5" to 10" wheel, I think.
> 
> The 19" option on Audi A6 C6's were 8.5J et48 with 255/35/19.


So if the same tyre will fit 8.5 and 9, would that mean they have the same contact patch?

I'm looking for some new wheels but can't find any 9's I like/in my price range. However, I don't want to loose 2 inches of contact area.


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## ReTTro fit (Nov 9, 2014)

2 inches ???

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## Tm99099 (Mar 14, 2017)

Contact patch shouldn't be affected. Only thing you'll notice is that the tyre stretch on the 9" may make the tyre wall appear a little dfferent than on teh 8.5" rim.


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## iamnotthestig (Feb 28, 2016)

ReTTro fit said:


> 2 inches ???
> 
> Sent from my iPhone using Tapatalk


Half an inch per corner.



Tm99099 said:


> Contact patch shouldn't be affected. Only thing you'll notice is that the tyre stretch on the 9" may make the tyre wall appear a little dfferent than on teh 8.5" rim.


Appearance doesn't other me so much. Just don't any negative effect with handling/grip downsizing to 8.5J


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## ReTTro fit (Nov 9, 2014)

That's wheel width, you won't loose any contact patch if your still running 255 tyres

Personally I think 255 is too much for a 8.5j rim 
I run 8.5j wheels with a 245 tyre

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## iamnotthestig (Feb 28, 2016)

ReTTro fit said:


> ...
> Personally I think 255 is too much for a 8.5j rim
> I run 8.5j wheels with a 245 tyre


Wouldn't that be a 10 mm? loss per tyre? 
Even still i'm not so sure that loss would make much if any difference.


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## ReTTro fit (Nov 9, 2014)

Correct mate but if he wants to run 255 on a 8.5j he won't loose any

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