my new wheels 18 inch AC schnitzer reps - tyres?

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spurs fan in a coupe
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my new wheels 18 inch AC schnitzer reps - tyres?

Post by spurs fan in a coupe »

Morning everyone

Well I have purchased my 5th set of wheels for the Zed.

These are my next project.

Just a quick question about tyres

The wheels are (all)
ET38
18x8.5J

What tyre size do I need?

255/35 rear
225 or 235/40 front?

They have come with a real mixture of tyres!

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Dav
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Post by Dav »

Personally I would go 225/40/18 front and 255/35/18 rear.
This will keep the rolling radius front and rear to within 0.24%
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Jonttt
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Post by Jonttt »

Front can be either 225 or 235's

I've gone for 235's to give a bit more rim protection but depends on tyre if you need to or not (I'm nt bothered about the slight differnece in rolling radius).
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simonbud100
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Post by simonbud100 »

Dav wrote:Personally I would go 225/40/18 front and 255/35/18 rear.
Sorry to ask a thick question but why have a lower profile on the rear? My car is fitted with exactly the same fitments as above, hence the question. :?:
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fwj01
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Post by fwj01 »

These are the sites that I used when choosing tyres for mine:

http://www.willtheyfit.com/index.php?wi ... mit=Submit

http://www.tyrestretch.com/

Hope it helps!!
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Dav
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Post by Dav »

simonbud100 wrote:
Dav wrote:Personally I would go 225/40/18 front and 255/35/18 rear.
Sorry to ask a thick question but why have a lower profile on the rear? My car is fitted with exactly the same fitments as above, hence the question. :?:
You are trying to keep the diameter of the front and back almost the same.
The overall diameter is made up of the wheel, in this case 18 inches, plus the section height of the tyre. The section height is the distance from the wheel rim to the edge of the tyre.
The section height is calculated by taking a percentage of the width of the tyre.
In your case, in simple terms, 225/40 (fronts) the tyre is 225mm wide with a 40 profile so 40% of 225 is 90mm. The rears are 255/35 so this is 255mm wide and the profile is 35 so 35% of 255 is 89.25mm and therefore the fronts and rears are keeping almost identical diameters.
Hope this helps
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simonbud100
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Post by simonbud100 »

Thanks Dav, you learn something new every day :!:
spurs fan in a coupe
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Post by spurs fan in a coupe »

Fitted today, Continental Contact sport 3 on rears 255 35 18 and pirelli rossa 235 40 18 on front.

Not sure the pirellis will last long, seemed a little scuttley on the way to the body shop for my nose job!

I like the look of them though!

What do you lads and lasses think?

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Gazza
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Post by Gazza »

I like :)
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Gazza
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Post by Gazza »

I like :)
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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spurs fan in a coupe
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Post by spurs fan in a coupe »

garythefish wrote:I like :)
Thanks!

I love your growing collection, no idea what the phoenix yellow US muscle car is but I love it!

Merry Christmas Gary (and everyone else!)
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Post by gookah »

Bit like my old ones,

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Last edited by gookah on Mon 19 Dec, 2011 17:25, edited 2 times in total.
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Post by spurs fan in a coupe »

gookah wrote:Bit like my old ones,

:D

Very like your old ones, I do have a plan for these in the new year to make them look a bit more special!
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stupot50
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by stupot50 »

Gents, need a bit of help please. I have similar 18 inch 8.5J wheels but appear to have a ET40 offset. The fronts are fitted with 235/40 and the rears 245/40. I need to replace all 4 tyres and am concerned about the fronts as they currently appear to foul the inner arch on full lock. What size tyres should I be fitting (front and rear) and do I require spacers?

Thanks in advance
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Gazza
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

225/40/18 shouldn't give you any problems
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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stupot50
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by stupot50 »

On the fronts only Gaz? Was thinking 225/35 on the rear?
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Gazza
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

225 on the rear will look a little small IMO

Spacers aren't needed on the front with 8.5" and ET40

245/45 is normal for the rear even on 7.5" rims
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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TitanTim
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by TitanTim »

The Schnitzers on mine 8.5x18 ET43 or ET36 with 7mm spacers front and rear were fitted with 225/40 fronts and 255/35 rears. IMHO 235 is too wide for the fronts and increases the possibility of tramlining.

I'm now running 225/40 on 8x18 rims front and rear and in all honesty they look fine on the rears, yes you don't quite get that wide tyre stance when looking at the rear but the biggest bonus I've found is in the handling, the Zed just feels much more nimble and chuckable in the corners. The wider rears somehow seem to make the car more leaden and slow whitted. With going for all season tyres which are softer compound the ride is much better too :)

Tim.
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Gazza
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

TitanTim wrote:The Schnitzers on mine 8.5x18 ET43 or ET36 with 7mm spacers front

Tim.
The addition of spacers does not alter the ET of the rim. The ET is the measure of offset from the centre line of the wheel to the mounting surface.

The higher ET puts the mounting surface toward the outside of the rim.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by TitanTim »

Gazza wrote:
TitanTim wrote:The Schnitzers on mine 8.5x18 ET43 or ET36 with 7mm spacers front

Tim.
The addition of spacers does not alter the ET of the rim. The ET is the measure of offset from the centre line of the wheel to the mounting surface.

The higher ET puts the mounting surface toward the outside of the rim.
Not physically but theoretically :| for e.g. a wheel with an offset of ET43 if you fitted a 7mm spacer pushes it out making it in theory the same as wheel that was manufacutured with an ET36 offset? i.e. it makes the offset lower or am I talking :dunce: or should read the :rtm: :)

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by siwilson »

Correct, if you add a 10mm spacer it effectively reduces the offset of the wheel by 10mm.

ET43 Wheel + 10mm spacer = Effective ET33
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by TitanTim »

siwilson wrote:Correct, if you add a 10mm spacer it effectively reduces the offset of the wheel by 10mm.

ET43 Wheel + 10mm spacer = Effective ET33
Cheers si thats kinda what I was thinking :)

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

You're both wrong.

Theoretical and effective don't come into it, by adding spacers you only change the position of the whole rim relative to the mounting surface. ET or offset is the difference between mounting surface and the edge of the rim.

If I stand on a 6" box I'm not now 6'6" tall, I'm still 6' but standing on a box ! :lol:
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by TitanTim »

Gazza wrote:You're both wrong.

Theoretical and effective don't come into it, by adding spacers you only change the position of the whole rim relative to the mounting surface. ET or offset is the difference between mounting surface and the edge of the rim.

If I stand on a 6" box I'm not now 6'6" tall, I'm still 6' but standing on a box ! :lol:
I'm still not convinced Gary I know what your saying though :wink

Surely fitting spacers changes that difference as you say between the hub and outer face of the rim and that's the change in offset:?

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Gazza
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

Fitting spacers only pushes the whole rim out, the ET of the wheel remains the same.

Perhaps this will make it clearer http://www.1010tires.com/WheelOffsetCalculator.asp
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by gookah »

Gazza wrote:Fitting spacers only pushes the whole rim out, the ET of the wheel remains the same.

Perhaps this will make it clearer http://www.1010tires.com/WheelOffsetCalculator.asp

AC spacers are permanently fitted to the wheel using a spring clip so that they are always on the wheel, and are not fitted to the hub, so this has indeed made the 'wheel' a different offset as the position of the mating faces is now different..... :wink:
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Z3cade »

I'm afraid your all wrong..

Spacers = cool dude 8-)

No spacers = booooo! :dunce:

Nuff said..
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Gazza
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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

gookah wrote:
Gazza wrote:Fitting spacers only pushes the whole rim out, the ET of the wheel remains the same.

Perhaps this will make it clearer http://www.1010tires.com/WheelOffsetCalculator.asp

AC spacers are permanently fitted to the wheel using a spring clip so that they are always on the wheel, and are not fitted to the hub, so this has indeed made the 'wheel' a different offset as the position of the mating faces is now different..... :wink:

Agreed, the wheel now has a different offset/ET

Fitting a spacer to the hub does not change the offset/ET of the wheel, fitting a spacer to the wheel does. It is the relationship between centreline of the wheel to the mounting surface of the wheel that gives the offset/ET figure.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Re: my new wheels 18 inch AC schnitzer reps - tyres?

Post by Gazza »

The box doesn't change my height, only my relationship to the ground.

If the box was surgically applied to my feet then I would have a height of 6'6"

Think of the spacer as the box ;)
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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