Correct wheel sizes query

Hi All,

I have the factory standard alloy wheels and tyres which are 195/55 R14. Assuming my calculations are correct, the overall size of the wheel and tyre would be;
14 inches = 355.6mm + (55% of 195 = 107.25mm) total = 462.85mm in diameter.

As this would be the diameter at which the speedo is calibrated to, I really need to keep any replacements the same size overall. If I increase the overall wheel size then I lose out on acceleration a little bit etc etc.

I have got my eyes on some nice OZ Racing superturismo wheels someone has had sprayed a dark grey which would awesome on my grey pulsar. But these are 16 inch and already have tyres which I would need to change.

Assuming I got these then 16 inches = 406.4mm which only gives me 56.45mm for the tyres so I would be looking at getting some 195/30 R16 tyres which seem almost impossible to get. If I got 195/40R16's then this would put the overall size at 484.4mm which is 22mm wider than the standard wheels, Would I be better off getting 15 inch wheels? or does the size increase not really matter?

I think your over thinking it to much .... no speedo is that accurate i think to big a wheel spoils the handling imo but plenty of people running 17s without any issues i got 15s with 40 profile on mine at the minute but wouldnt be adverse to 16s ... it also depends on what you are using it for if its road use then lower profile tyres will suit 40s is fine you dont want to be running rubber bands ....

It changes it a lot less than you think and are speedo unit is 15+ year old and probably outlet anyway. If you have real concern there are places to calibrate them as my last R had print out

I think i'll go for some 16's with a 40 profile. its only for road use, I was mainly concerned about losing acceleration but wasn't sure how much an extra inch in overall diameter would make a difference

Even 16's with a 45 profile would be fine.

I run 205/45-16's. As everyone has said the speedo aren't very accurate

http://www.willtheyfit.com/index.php?width=195&aspect=55&diameter=14&wheelwidth=6.5&offset=40&width2=205&aspect2=45&wheel_size=16&wheel_width=9-5&offset2=40

I used this site