Hey guys,
I recently bought an 02 Civic and the car came with some 18' Konig Rated R rims and Yokohoma Parada Spec 2 tires. They make a lot of noise and the ride is not as comfortable, so I will be taking them off and putting some stock rims and tires for now. I was wondering however if these current rims and tires have any effect on speedometer and odometer readings? Just wanna make sure i'm going the speed my car states I am going.

yes by about 2-3mph

Go here for a nifty tire calc:
http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMathNS.jsp

Rim size has no affect on the spedometer calibration. It's the size of the tires that you need to pay attention to. 45 series will be smaller than 50 series etc...

ppl still have Rated Rs??!?!?!?!

Rim size has no affect on the spedometer calibration. It's the size of the tires that you need to pay attention to. 45 series will be smaller than 50 series etc...
tire size depends on rim size so ur wrong and right