Accuracy of Speedometer with 17" Rims?

Hi to all. I bought my ViVi just about a month ago, and have dropped in a few add-ons to my new ride.

So, my question is: since my ViVi is running on 17" with 205/40/17, the change of the wheels/tyres' overall radius is sure to affect the accuracy of the speedometer, but is the actual speed faster/slower than what the meter shows? For example, my speedometer reads 120kph, what would be the actual speed taht I'm travelling at?

I totally suck at MATH, so...... any math geniuses here? Pls help, curiosity really kills dude!!! And, oh, BTW, thanx in advance!!!

qam: when ur speedo read 100kph... ur real speed is 102.2kph

here r tire size calculator.....
http://www.miata.net/garage/tirecalc.html

Thanx a bunch, bro. What about odometer I masuk RM85 that day, managed 430km (dunno if it's the actual distance leh...) and it starts blinking, is that considered ok or not?? What's the longest distance for other ViVians out there

odo not very sure wheter got effect or not...
mine rm50 new price travel for 300km on 15''.

Wah, that's way better than my Kelisa woh!! Anyhow, thanx again!!

mine RM90 = 450km

perghhh
mine...RM75 from seri kembangan to KULIM
it is ok or not???

perfectly!!!

So far w da new pricing, a tank-full for me is roughly RM85. I managed 439km on 17" wheels, considered more or less ok lah. My kelisa b4 price hike was RM58/tank w average 430km on 14", which translated to RM82 for 430km lah...

My myvi can go 380km for RM55 with my 17" sport rim (Taiwan)..is it ok?

usually full tank of petrol our myvi can go around +-400km intown, 450-500km long distance, hantu drive +-380km.
a full tank of petrol +-35liter.

my opinion ler, hav to check my driving book la.
haha...

the topic here is about speedometer,
here r links to calculate your speedo with original rim of myvi 175/60/14.

http://www.rims-n-tires.com/rt_specs.jsp

http://www.kouki.co.uk/utilities/visual-tyre-size-calculator

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

TQ!
mine is 195/55/15,
When speedometer reads 60mph (96.6km/h) actual speed will be 63.1mph (101.6km/h): 5.2% faster.
my fastest speedo is 175, actual speed is? 184?
aduyaiii...kantoi la math... sori.