sld

I'm planning on 18s with 245/40/18s all the way around. Is my speedo gonna be off? If so, is there an adjustment that needs to be made?

Lvangundy

Try this.

http://www.powerdog.com/tiresize.cgi

Enter the stock tire specs first then enter your new tire specs.

Look at the "difference" column and the "sidewall" column. If the second set (new wheels) has a positive difference then your new wheels will be spinning more times than your stock wheels. This means your speedometer will be reporting a speed slower than you are actually going. In my case with a 1% difference my speedometer is 1mph off. 60mph on the speedo actually is 61mph.


There was another discussion about this for LS cars here ..

https://www.clublexus.com/forums/sho...threadid=70931

evolon5150

I have the same size and didn't feel or see any changes in the speedo. but maybe it so little I couldn't tell the difference.

sld

Lvangundy, thanks. The difference will be 0.1%

GS4Will

if you stay within 3% of stock's overall diameter, you are ok