I currently have 20in iforged wheels with 275 30 20 and 245 35 20 on them... my tires are pretty much worn out. After doing some research it seems that 285 30 20 actually matches the factory 19in tire height almost exactly compared to the 275 being smaller. I also found that the 245 35 20 seems to be to tall for the front that theres suppose to be a .75 inch diff from the front to rear which would mean a 255 30 20 would match the factory front sizing perfectly also...

Any oppinions im not worried about rubbing. I just dont want to have any issues with the vdc right now if i slam 2nd gear it seems like it cuts my power some even with the vdc off im not sure if thats effecting it or if its related to the vdc never being fully disabled thanks...

 

yes 255/30/20 and 285/30/20 are the closest sizes to stock 18" wheels.

 

can anyone else second this thanks

 

second, 245/30/20 and 275/30/20 work also

 

i have 255 front and 275 rear.. i an't go bigger in rear i will rub..

 

stock 225/45/18 is 25.97" diameter, 255/30/20 is 26.02" diameter.

stock 245/45/18 is 26.68" diameter, 285/30/20 is 26.73" diameter.

you can't get any closer then that.

 

Rule of thumb is to stay within 3% of the Original diameter. Within that 3% there are a couple different sizes that meet that criteria including the tires you had before.

 

lots of people run 255/30/20 and 285/30/20. its what i would get if i go 20s.

 

245 35 20 seems popular and is whats on the wheels right now but if i drive for 50 miles or so a little check light comes on then if i turn the car off and back on it goes away.... im thinking its something with the vdc... The more ive researched 245 35 is a little to tall... just 255 30 is a rare size thanks guys

 

so when you change the number in the middle from 255/35/20 to a 255/30/20 you will make the tire skinnier height wise? i am confuse now.. because the set up for front is 245/35 or 255/35

 

http://www.miata.net/garage/tirecalc.html
Plug in the stock size and then compare it to the 20" tire sizes, and find one that is within 3% of the stock diameter

 

ive got 255/30/20 up front and 275/30/20 pirelli's. im switching to th ps2's and going with either 245/30 or 255/30 up front and 285/30 in the rear

 

I'm planning on running 245/35/20 and 285/30/20 and someone told me that this isn't a good combo. They said something about having noticable understeer. Can anyone comment?

 

http://www.bigcustomwheels.com/info_specs.jsp

that site is awesome... a lot like what redlude posted up