Alright guys..here we go.
I have 245/30/20 on 8.5 " wheels in the front and 275/30/20 on 10" wide wheels in the rear. 03 non brembo coupe...I dont like the way the 275/30/20's dont fill out the rims so im changing to 285's. However I also dont like the profile of the 30 series in the front(too low). First question. Would it look ok to have a 35 series in the front with a 30 series in the rear? I would go with 35 series all around but im told they wont fit?? the offset on the rear wheels are 25mm. Any help would be great..

 

yeah...it would look ok...you can and should do 245/35/20 in the front no prob...but i would stick to 275/30/20 in the rear to have more of the same diameter all around...

 

The only problem that i have is that the tire does not fill out the rim. It is back set and looks incorrect. It creates a weird gap. Thanks for your input..I think i will stay with the 30 series and go to the 285 in the rear

 

a 255/30/20 (26.03") in the front will be as close to stock (25.98") diameter as you can get. The 245/30/20 (26.76") will be too big.

stick with the 285/30/20 in the rear it's also closer to stock then the 275/30/20.

 

Ok im a little confused your speaking of diameter right? what is the difference between the two ..245-or 255 the diameter isnt changing the width is. Am I wrong here? Did you mean the 245/35/20 will be too big? Thanks for the input on the rears.

 

SERIES is a percentage of the width.It is not actual size.If you go wider in size ,the diameter will also increase.That is why there are different series.A 245/35/ will be the same overall diameter as a 285/30 will be.If you are still confused ,go to a tire mfg.website and it will explain the details to you.

 

what he said....the series of a tire is the aspect ratio. it's a measurement of the sidewall height of a tire. the overall diameter of the tire is = the rim size + 2 (sidewall height).
The sidewall height is the aspect ratio x tire width (this is in mm and needs to be converted to inches).

here's a few sizes for you to compare.
for the front:
225/45/18 = 25.98"

245/30/20 = 25.79"
245/35/20 = 26.76"
255/30/20 = 26.03"<-----best choice
255/35/20 = 27.03"

for the rear:
245/45/18 = 26.69"

275/30/20 = 26.50"
275/35/20 = 27.58"
285/30/20 = 26.74"<-----best choice
285/35/20 = 27.86"
305/30/20 = 27.21"

 

You guys rock! Thanks for the help. My problems have been solved. I will now leave you alone!