How much change in the speedo occurs when you change you tire size and how would you adjust? Just move the needle or something? Thanks.

 

What you want to do when you upgrade your tires and wheels is to keep the overall diameter same so you don't have to deal with speedometer error.

And no, you can't just move the needle as Maximas have electric speedometers.

Try this handy link.

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

You can't get a perfect match in tire diameters going to a different size, but a few percentage points are acceptable.

With a Plus One upgrade (1" larger diameter wheels), you'd want to go with 215/55R16 tires.

With a Plus Two upgrade (2" larger diamter wheels), 235/45/17 seems about right.

 

if you had 16x 7 rims,would 225 45 16 be ok?i think the 215 55 16 would look too big since my car is lowered.if not what size will look good?

 

Hey thanks. What would be the tire size if i got a 17x8 or 17x8.5? I've seen the 4th gens with that wide of a tire, do you think those would fit on the 3rd? Thanks.

 

235/45/17 is a very agressive width. . . .

 

I agree 235 does seem a little agressive, to. I have 215/50/17s and they work nicely. I think any wider and I would be rubbing all over the place.

 

by aggressive i mean good that's what size i'm gonna go with. hehehe you need that extra rubber!

 

could someone explain the first two numbers?? i.e. 235/45 Thanks.

 

235 is the width of the tire in millimeters, 45 is the aspect ratio. What aspect ratio means is the height of the sidewall of the tire as a percentage of the width. So on a 235/45 tire, the side wall height is 45% of 235mm which is about 105.75 mm.

Try the link for more details.

http://www.continentaltire.com/educatio.cfm

 

see my reply in samabra's thread