tyre size help/advice needed

[matttingle]

i'm upgrading to 17" wheels

i though i needed 205/50/17....?

i have been offers 225/45/17.....apparently they give better footprint - will ther be much difference?? any help appreciated as this is alien to me!!

[redmeganematt]

not to sure if the will fit in the arch should do though the big enough lol. but they will knock your speed down. E.G if your doing 70 mph on the speedo your actual speed will be 69.73mph not a big difference but it counts.
here is a link to a tyre calculator http://www.alloywheels.com/tyrecalc.asp

[matttingle]

cheers - looked on there and if speedo says 70mph i'll be doing 70.27 or something similar............... think i'll go ahead with them