BruteSBC

hey all, im new here, i had a quick question. i know stock size is 205/65/15, but i haev a gift certificate to summit racing that i got for christmas, and i like these tires alot, but sadly they are only listed in 215/65/15. i dont think ill have any rubbing issues with the tire but i just wanna ask to double check. here is a link to the tire, please let me know what you think as well.

http://store.summitracing.com/defaul...0&autoview=sku


thanks
mike

Kohinoor

iTrader: (22)

i doubt itll rub, but you speedometer will be off a lil bit and your tire will have a lot of "fat" on it

Lexbox

lol Get some white walls while your at it.

BruteSBC

well to my understanding, the aspect ratio is still the same, and the wheel size is the same, its just alittle bit wider than stock. so why would my speedo be off?

Woogie

Because you've got more sidewall.

flipside909

Here's a very old but very useful tool:

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

Stock Tire: 205/65R15

Sidewall 5.2"
Radius 12.7"
Diameter 25.5"
Circumference 80.1"
Revolutions/Mile 791.0

215/65R15
Sidewall 5.5"
Radius 12.7
Diameter 25.5"
Circumference 80.1"
Revolutions/Mile 776.0

As you can see, there is a huge difference. Going with a 215/65R15 tire will cause your speedo to read slower than it actually should be...and ultimately under calculating your measured mileage as there are 15 less revs/min.

RA40

iTrader: (6)

In addition to Flip's post, here is some data from a Michelin XGT-H4 taken from Tire Rack

205/65 HR15
width 8.4"
diameter 25.4"
revolutions 827

215/60 HR15
width 8.8"
diameter 25.3"
revolutions 832

215/65 HR15
width 8.8"
diameter 25.9"
revolutions 790