Is that true re: odometer logging 2.1% more miles? I was googling for an answer to how tire sizes affect the odometer, and found a post by someone on a forum stating the above. I couldn't find a definitive answer by googling.

 

i would think so... your car thinks you are going faster than you are, so it will think you are traveling greater distances at once.

 

but the bigger radius the slower the speedometer reads.... isn't it?like for example.... under 1000 turns of the wheel... the smaller radius of the wheel go shorter distance...
so if u run a bigger rim and bigger tire...... the meter reads slower....

 

Well, going from a 225/50/17 to 225/45/17, the new (45 series) tire's radius is 0.4" smaller than the stock tires. So, the speedo reads 3.4% too fast. I'm only talking about changing the tire, have no idea how changing the rim would affect things.

If it actually does affect the odo. do/can Nissan dealers recaliberate the comp. to compensate for the decrease in radius?

 

you can change your rims if you want with no problems, as long as a you adjust the tire size to compensate for the size difference. i have 235/45/17's on my stock rims and its really close to the factory specs.

 

AAA has speedometer recalculating adjustment expo kinda things over here in CA to help you adust it, or atleast tell you by how much its off... its free for members

just use the tire calculator to figure out how much it will change your diameter by... not a big deal