On Mon, 11 Aug 2003 01:12:20 +0800, "Lim PE" <sickend@zdnetmail.com>
wrote:

>| > where can one obtain the driven gear (or whatever it is called)
>| > that would correct the speedometer for the above current tire size?
>
>If you know your gear ( top & final ) ratios, & you measure the height
>of centre of drive axle, you can calculate car speed @ different rpm,
>then type stickers for the maximum legal speeds, put these stickers on
>your tachometer : when you want to drive @ the legal speed limits, chk
>these stickers ( on your tachometer ) instead of speedometer.
>
>E.g. for an accord @ 3000 rpm : tyre's effective radius ( e.g. 30cm for
>a 205/65R15 @2.3kg/cm² ) & calculation of ratio ( 0.731 x 4.285 =
>3.1323 ) will imply that tyres will spin 3000 ÷ 3.1323 = 957.76 rpm =
>57465.75 rph. Tyre's effective circumference is 2 x 22/7 x 30cm =
>188.57cm = 0.0018857 km, so car speed ( assuming 100% grip, zero
>toe-in ) is 57465.75 rph x 0.0018857 km = 108.36 kph = 67.33 mph
>70 mph will need 70 ÷ 67.33 x 3000 rpm = 3118.9 rpm.
>
Here is a great little program which actually calculates this for you.
btw, I scanned this for viruses when I DL this morning and it's clean.
as of VDAT 8/15/03 from Mcafee......
Hope this helps
PT