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18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 12:42 am
by Nastypsychoboy
Time for a new set of rims one of my originals has been savaged by a pot hole and i've got a few questions before parting with my cash:

Q: Anyone tried putting wider wheels on the rear? 8.0s on the front and 9.5s on the rear? Is this even advisable? Or would cornering become a hazzard? Think it looks pretty sweet on the M5s but they're 2 wheel drive.

Q:Anyone know if 19inch rims x 9.5 on the rear under original suspension will fit? And do they go over over speed bumps?

Cheers
8)

RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 8:52 am
by jimbo1234567
ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round

RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 10:32 am
by gareth215
I think it might be important to keep the rolling radius the same for front and rear wheels exactly the same on a four wheel drive car as I know some four wheel drive cars can ecperience early wear on the centre diff. Not sure if this is an issue on the RS4 I am sure someone on here will know, for example 911 (even 4x4 models) have wider rear wheels but due different profile tyres the rolling radius could be the same? There is a calculator on line at http://www.pneus-online.co.uk/tyre-equi ... dvice.html which may help.

Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 11:58 am
by ollys
jimbo1234567 wrote:ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round
Jim,

did the springs arrive?

Olly

Posted: Fri May 01, 2009 3:29 pm
by davs4
I've got 19"x 9" ET 27 with 15mm spacers on 265/30 tyres, no issues :D

Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 5:36 pm
by Nastypsychoboy
jimbo1234567 wrote:ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round
Thanks for the replys very interesting, Jimbo are your 19 x 9.5s the MTM ones in the Youtube vid?

Gareth good point, but would that only effect me if i was putting 18s on the front and 19s on the rear?

Very very tempted to 19 x 8.0 on the front and 19 x 9.5 on the rear.

Davs4 & Jimbo what does the et 27/20 mean?

:D

RE: Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Fri May 01, 2009 5:50 pm
by davs4
Et=Offset
The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel. The offset can be one of three types.

Zero Offset

The hub mounting surface is even with the centerline of the wheel.

Positive

The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.

Negative

The hub mounting surface is toward the back or brake side of the wheels centerline. "Deep dish" wheels are typically a negative offset.

If the offset of the wheel is not correct for the car, the handling can be adversely affected. When the width of the wheel changes, the offset also changes numerically. If the offset were to stay the same while you added width, the additional width would be split evenly between the inside and outside. For most cars, this won't work correctly.

Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Wed May 06, 2009 3:38 pm
by gareth215
Nastypsychoboy wrote:
jimbo1234567 wrote:ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round
Thanks for the replys very interesting, Jimbo are your 19 x 9.5s the MTM ones in the Youtube vid?

Gareth good point, but would that only effect me if i was putting 18s on the front and 19s on the rear?

Very very tempted to 19 x 8.0 on the front and 19 x 9.5 on the rear.

Davs4 & Jimbo what does the et 27/20 mean?

:D
no if you have wider rear wheels you could change the rolling radius. The profile of a tyre eg in the standard 255/35/18 tyre is the 35 which means the side walls are 35% of the tyre width or 17.5% for each side of the tyre wall. so if you went up to 275/35/18 the side walls would be 35% of 275mm not 255 mm which will make a bit of difference. I am not sure how much is too much but if you go on http://www.pneus-online.co.uk/tyre-equi ... dvice.html you can have a play arround and see what will get you the closest to the fronts. i.e 275/30/18 may work out about the same. Hope that helps

Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Wed May 06, 2009 3:51 pm
by dace
jimbo1234567 wrote:ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round
Same for me with ET30 and 10mm hubcentric spacers. No issues on road or track. So much more planted especially with 275 rubber.

Jim how did Croft go?

Posted: Wed May 06, 2009 5:58 pm
by Nastypsychoboy
Of course Gareth :roll: , all makes sense now.

Thanks for all the positive feedback on putting the 19s on, think ive been convinced. Would 18s be better for handling tho and 19s for cruising?

One last Q:

18 x 8.0 - 5 x 112 ET 38 - 225/40 or 35 R19?

19 x 8.0 - 5 x 112 ET 35 - 225/35 R19

Preferences please. And will the 19s fit without any issues or spacers?

Cheers.
Nearly there!..... :D

Posted: Wed May 06, 2009 6:33 pm
by dace
In order to achieve the correct offset you will need spacers on those wheels. B5 RS4 is ET20.

Posted: Wed May 06, 2009 7:17 pm
by Jhcolling
I have 19x8.5 fronts (225/35 tyres) and 9.5x19 (255/30 tyres) radius is the same. I have no issues.

Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Thu May 07, 2009 12:00 am
by jimbo1234567
dace wrote:
jimbo1234567 wrote:ive got 9.5 x 19 et 20 wheels with 275/30 19 tyres and no probs all round
Same for me with ET30 and 10mm hubcentric spacers. No issues on road or track. So much more planted especially with 275 rubber.

Jim how did Croft go?

awesome dave, cant wait to do another :D the "seven second croft king" movie will be coming soon. dont get too excited though , it doesnt last long :shock:

RE: Re: RE: 18s or 19s? 8.0 or 9.5 on the rear?

Posted: Thu May 07, 2009 7:36 am
by dace
Bloody hell 7 seconds, come on surely you have more.....