My snows are just about bald on my maxima and more snow is headed our way. Right now I have 205/65/r15's on the sawblades but we have a set of studded 205/70/r15's that some guy at my dad's work gave him. How much will the jump from an aspect ration of 65 to 70 throw off my spedometer? Will it read faster or slower than I'm actually going? Will it affect driveablity?

 

I'm sure this site is in the stickies somewhere
http://www.miata.net/garage/tirecalc.html

 

I'll throw off your speedometer (and odometer) by a -3.2%, and your speedometer will read 60mph when you are really going 62mph. Some tire website recommended to keep the percentage change under 3 percent, but it shouldn't make a difference, except for speeding tickets. The 205mm wide tire should be good in the snow, because any wider sized tires would distribute the car's weight over more tread, reducing the pressure exerted per square inch on the pavement and consequently less traction in snow. The studs are great for driving in snow, but check your local laws for studded tires.

Any other questions on how changes in tread width/aspect ratio/wheel size can be answered by using this link: http://www.miata.net/garage/tirecalc.html

BTW - this link is in the Stickies if you knew where to look.

 

Craig, you must type faster than me.

 

hehe, I just typed less than you and didn't elaborate on any of the differences

 

I am running 215/70/15's and they are fine




Brian

 

Cool - Thanks guys - I guess I'll get them put on monday when I get my car aligned... They were free so I'm not losing anythign but spedo accuracy + the cost of mounting/balancing.

 

same thing here, free tires, just paid $1 for rims + shipping and then for mounting...

Brian