wats 205/40/17 then wat kind of difference just like to know as i hav sum new 17s going on!!! i know it will below if you going 30mph abt prop 28mph on 17s!!

D4 runs at the limiter in 4th on 195/45/16 @ 102mph and reads 98mph. This goes to pot after 100mph though :lol:

but i sit next to ppl goin thru cameras... and my clock is bout 10mph under the speed of the camera....
its not really important... but thought i would say lol..

xhale2007: yeh u know wot i meant.

dont forget the speedo reads slow anyway, so you are actually doing the right speed .

Specification - Sidewall - Radius - Diameter - Circumference - Revs/Mile - Difference
185/65-14_____4.7in __11.7in___23.5in______73.7in______859____ 0.0%
195/40-16_____3.1in __11.1in___22.1in______69.6in______911____-5.7%
195/45-16_____3.5in __11.5in___22.9in______72.0in______880____-2.4%
195/45-15_____3.5in __11.0in___21.9in______68.8in______921____-6.6%
215/35-17_____3.0in __11.5in___22.9in______72.0in______880____-2.3%



Well I did these tyre sizes on that website you've just given and according to that out of all the tyre sizes above the original wheel has a greater rolling radius? How come? :boggle:

Think there calculations are wrong! :lol:

[Edited on 09-05-2003 by Patrick]

this will tell you how much your speedo is out

http://www.miata.net/garage/tirecalc.html

At 40mph, your clocks DONT read 48 with 16's. In fact at those speeds the increase is negligable. Its at 60+ where the rolling radius increases dramatically, and its not as if you have 18's either.

:lol:

do ya mean 48 ;)

is there anyway to adjust this!!? its quite annoyin for cameras.

e.g 40 on the clock = 58!!

im getin 40 profiles cos they rub like a bitch.