205/45/R17 to 225/40/R18 on EP3 Type-R?

[Durzel]

I need to get some new tyres for my EP3 Type-R, my current Michelin PS2s are 225/35/R18 and I was really hoping to get some Super Sports after having good reviews about them. The stock 17" wheels come with 205/45/R17 Bridgestones.

Unfortunately they only seem to come in 40 profile on 18" diameter. Would these be ok to use or am I going to lose performance and/or throw my speedo out massively?

Thanks in advance

[Glosphil]

The 40 profile rather than 35 will raise the overall gearing by just about 3-1/2%. So you speedo will under-read by that amount. As you speedo almost certainly currently over reads by at least that much it shouldn't be a problem. I doubt you will notice any difference in performance, but the ride quality may improve slightly.

[Durzel]

Thanks