05gen7ex

So i have the opportunity to buy a set of 16" fit rims for $200. But i have a couple questions, Larger rims will throw off my speedometer, so is there a way to get this fixed? I had smaller tires n the front for a while til i could get new ones and the speedo was 5mph faster than was going. also could i get a lower profile tire to make the total diameter the same? any help would be appreciated... Sorry for the noob ?

MindBomber

You've got the right idea. Just buy a lower profile tire to make the overall diameter match, there's nothing else you can do.

05gen7ex

sweet thanks.

Speed9117

iTrader: (1)

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

Here's a cool little tool to help you tell how much your speedo is going to be off or what size tires you should buy so it is not off.

sl33pyriceboi

iTrader: (3)

^thats not extremely accurate because it doesnt account for the actual rim diameter that the tire is placed on.

Speed9117

iTrader: (1)

you mean rim width? like if your tire was stretched at all?

I know it's not totally accurate, but it's worked very well for me. I've used that to figure about how low my speedo should be and then I've gone out and found those "what's your speed" radar boxes or timed speedo checks on the freeway and all three are in pretty good agreement. Not the best, but it will get you close anyway.

sl33pyriceboi

iTrader: (3)

yes, exactly what i mean (about stretching and pinching) but its pretty accurate most the time to about 1-2%