215/40/18 vs 225/40/18

[kovmps6]

saves me making another thread il ask my questions on here... best to go 225/40 over 225/45 on a stock 7.5 mps rim?

aslo what do people think is the best value for money tyre from the below :

New 225-40-18 PIRELLI PZERO NERO $185 each

New 225-40-18 PIRELLI PZERO NERO TYRES AUDI BMW VW MERC (eBay item 230579165768 end time 07-Feb-11 17:28:34 AEDST) : Cars, Bikes, Boats

4 X 225/40/18 KUMHO KU31 TYRES $200 each

4 X 225/40/18 KUMHO KU31 TYRES WRX GOLF ACCORD MAZDA6 (eBay item 280571221658 end time 02-Feb-11 21:29:44 AEDST) : Cars, Bikes, Boats

or Yokohama Avid S34 225/45/18 $200 each

Mazda RX8 Nissan 350Z Tyres 225/45/18 4 New Tyres (eBay item 310291404067 end time 06-Feb-11 16:09:52 AEDST) : Cars, Bikes, Boats

read a heap of other threads and ku31's are a goer... just wondering if anyone recommends the pirellis or those yokohamas before i start searching for a best price on the ku31's?

[Nexus]

on here... best to go 225/40 over 225/45 on a stock 7.5 mps rim?

Stock MPS rim is 7", not 7.5"
Following tyre manufacturer specifications strictly means that 225/45R18 is a better fitment than 225/40 to the stock 7" rims.

Most tyre manufacturers do not warrant 225/40R18 on 18x7 rims. There are a small number who do. Not all of their tyre models will - it's something to check on the specifications of each tyre.

On the other hand, I'm yet to see a 225/45R18 that isn't OK according to the tyre manufacturer to fit to the 7" stock rims. Hence I'd reccommend them.

Again - opinions will vary, and many people allow some leeway against the specs. 225/40R18 on the stockers is commonly fitted, but warning as above. Another example is 235/40R18 on 18x7.5". Most are not warranted on 7.5" rims, but a few are.

So - in summary - before the deluge of opinion in favour of 225/40R18 on stock rims and ignoring manufacturer specs arrives:
225/45R18 is a better fitment because 225/40R18 is not usually warrantable.
It is not usually warrantable because the fitment is usually outside the tyre manufacturers specifications.

[kovmps6]

Stock MPS rim is 7", not 7.5"
Following tyre manufacturer specifications strictly means that 225/45R18 is a better fitment than 225/40 to the stock 7" rims.

Most tyre manufacturers do not warrant 225/40R18 on 18x7 rims. There are a small number who do. Not all of their tyre models will - it's something to check on the specifications of each tyre.

On the other hand, I'm yet to see a 225/45R18 that isn't OK according to the tyre manufacturer to fit to the 7" stock rims. Hence I'd reccommend them.

Again - opinions will vary, and many people allow some leeway against the specs. 225/40R18 on the stockers is commonly fitted, but warning as above. Another example is 235/40R18 on 18x7.5". Most are not warranted on 7.5" rims, but a few are.

So - in summary - before the deluge of opinion in favour of 225/40R18 on stock rims and ignoring manufacturer specs arrives:
225/45R18 is a better fitment because 225/40R18 is not usually warrantable.
It is not usually warrantable because the fitment is usually outside the tyre manufacturers specifications.

i brought another set of mps6 wheels yesterday and the zigen boxes they come in had 18x7.5 written on them and thats why i got confused and forgot the stock ones are a 7 inch..

thanks for the feedback il investigate further with the tyre company i buy off.. wonder if there is issue with insurance..