Recommended tyre pressure for 225/45R18?

X_Splinter

Registered User
Hey there guys, today I am buy 18" alloys and I am going to use the 225/45R18 tyres.

Does anyone here that has 18 wheel from stock could check the recommend tyre pressure? It's usually on the drivers door.

I can't do it because mine only has 16 and 17 tyre displayed.
 

Zafi

Registered User
My B8.5 2.0 tdi S Line has 245/40 R 18 as standard, I think you have the wrong aspect ratio.

Pressures for 245/40 R 18 are 33 front 30 rear with partial loading, 35 front 38 rear fully laden
 

X_Splinter

Registered User
My B8.5 2.0 tdi S Line has 245/40 R 18 as standard, I think you have the wrong aspect ratio.

Pressures for 245/40 R 18 are 33 front 30 rear with partial loading, 35 front 38 rear fully laden
Thanks for the reply. The tyre was authorized by Audi. It has almost identical profile size of your tyre.

I saw a door sticker in another topic and I using the 245/40 XL pressure which is 36 33 with 3 people.

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Zafi

Registered User
Must be a different model to mine.
So you are running 18" low profile Winter tyres?
Thats a strange choice, better off running narrow tyres high profiles for more sidewall flex and smaller footprint hence better grip. I would run your standard wheels with Winters and big wheels for 3 seasons.
 
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X_Splinter

Registered User
Must be a different model to mine.
So you are running 18" low profile Winter tyres?
Thats a strange choice, better off running narrow tyres high profiles for more sidewall flex and smaller footprint hence better grip. I would run your standard wheels with Winters and big wheels for 3 seasons.
We don't have winter tyres here as there is no snow here.

Why I stayed with the 225? 245 would rise my mpg and lower acelaration. Sure they would provide better grip in dry roads.

Another reason for the 225 was the way it looks... the alloy is at the face of the tyre (no tyre belly).
 

RyanJonS4

Drive It Like You Stole It
M&S doesn't mean it's a dedicated winter or dedicated snow tyre and many 'summer' tyres carry the M&S marking. All it means is that it performs too an acceptable standard in tests in mud and snow.
 
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desertstorm

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So you are fitting 225 tyres because you like the stretch look and you think it will improve acceleration/ fuel economy . But your car currently only runs 16 or 17 inch wheels which will be more economical and probably give you better acceleration than the 18's you are fitting. Unless you are fitting really lightweight wheels .
http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested.
The 225/45/18 is only 1% bigger than a 245/40/18 tyre so the speedo calibration will be OK.
As for tyre pressures try 33F 36R the same as a 245/45/18 tyre.
 

X_Splinter

Registered User
So you are fitting 225 tyres because you like the stretch look and you think it will improve acceleration/ fuel economy . But your car currently only runs 16 or 17 inch wheels which will be more economical and probably give you better acceleration than the 18's you are fitting. Unless you are fitting really lightweight wheels .
http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested.
The 225/45/18 is only 1% bigger than a 245/40/18 tyre so the speedo calibration will be OK.
As for tyre pressures try 33F 36R the same as a 245/45/18 tyre.
I am saying better acceleration/fuel economy comparing to the wider 245 tyre.

I had 16". Now that I am with 18 I notice a drop of acelaration power but turning is much better
 

desertstorm

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I run 235/45/17 tyres and lightweight wheels on my 320bhp 3.0 TDI A4 and find them about the best compromise between traction, acceleration , ride quality and fuel economy. Plus they are a very common tyre size so decent tyres are cheap.
If you had 205 tyres before than the 225 will be giving you a lot more grip.
You will need to keep away from the kerbs though with stretched tyres as there isn't usually a lot of rim protection.
 

X_Splinter

Registered User
I run 235/45/17 tyres and lightweight wheels on my 320bhp 3.0 TDI A4 and find them about the best compromise between traction, acceleration , ride quality and fuel economy. Plus they are a very common tyre size so decent tyres are cheap.
If you had 205 tyres before than the 225 will be giving you a lot more grip.
You will need to keep away from the kerbs though with stretched tyres as there isn't usually a lot of rim protection.

With a powerful engine like that you can roll with any rotor and tyre size.

My 16" were on 225 tyres. I simply stayed with it.

Now I am very carefully parking to avoid touching the kerbs
 
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