my 20" rims have 275/30/20 rear and 245/35/20 Front.
I noticed that many ppls use 275/30/20 for rear instead of 275/35/20.
Does it really matter if it's 30 or 35 profile?

 

if you use 35 , you should use 35 profile front and back , same with 30. Either will work.

 

hmm.. i don't know why the previous owner used 35 front and 30 back.

Edit: i have a question about treadwear on the sidewall. WIll tires with higher treadwear number last longer than tires with lower treadwear?

 

I've had my 100 treadwear rating tires for 50k now, still tons of life left... -.-

http://en.wikipedia.org/wiki/Treadwear_rating

^^Took 10 seconds

 

most 20inch rim an tire package come like that for 350z

 

Maybe they were trying to get an equal sidewall height. Since the sidewall height of a 275/35 > 245/35

So maybe the 275/30-245/35 looks more equal

 

i like the 30 series out back muuuch better.

I had the 35 series for a long time, its a bit taller, and you can definately tell just by looking. Yeah, i wouldnt mix m match... i think 275 30 20 and 245 30 20 are a great combo for the car.

the tires are actually cheaper in the 30 series than the 35 series.. strange.

 

I already installed a new set of 245/35/20 in the front not too long ago, and now it's time for the rear. I"m looking at 275/35/20 KUMHO Ecsta SPT for $137. I read many good reviews on this tire. But it sucks that it's for summer.

 

Ding ding ding we have a winner. Most placed don't do the math or know that our cars need a stagger in tire height from front to rear.