Tyre question

[steve_nairn_sti]

Evening all,

I've got a set of 18's that are running on 225/35/18 rubber at the moment.  I'm about to be replacing the tyres and wanted to know if it would make a huge difference changing to 225/40/18's instead.

Also, I know it used to be an issue on the likes of Cav 4x4's that all four tyres should be changed at once.  Do you change all your tyres at once or would you happily do front pair only? 

Cheers,

Steve

EDIT - For clarification, if I was changing only two tyres I would keep aspect ratio that is on car at the moment.[y]

[dipsy]

When comes to new tyres i change all four.

[steven_williams]

I don't think it would normally but as you are going to a different aspect ratio it might do due to the greater difference in overall circumferance. I am sure someone more informed than me will be here in a bit. Steve

[terminator]

TRY THIS WEB PAGE. PUT IN THE STOCK TYRE AND THE NEW TYRE AND IT WILL GIVE U ALL THE INFO REQD.

www.miata.net/garage/tirecalc.html 

[steve_nairn_sti]

Thanks Terminator.

Anyone know what the stock size wheels are for a bugeye WRX???

[st3ph3n]

215/45/17 I think.

[steven_williams]

Very useful piece of information, thanks terminator.

[steve_nairn_sti]

Interesting...

Specification  Sidewall  Radius  Diameter  Circumference  Revs/Mile  Difference

215/45-17 3.8in  12.3in   24.6in 77.3in   819   0.0%

225/35-18 3.1in  12.1in   24.2in 76.0in   833 -1.7%

225/40-18 3.5in  12.5in   25.1in 78.8in   804   1.9%

Looks like neither size is perfect for my motor then....