Quick E63

I ordered my 20" Iforged wheels today and was told to run 245-30's up front and 285-25's on the rear... I told him I thought I was suppose to run 245-35 and 275-30's he said no.

What do you guys run on your 20" wheels?

Vetluver

I don't have 20's but most people on this forum have gone to 19s because of ride quality disturbance, also as I recall you can't put as wide a tire on 20s as you can on 19s without rubbing. If you are going to go with Michelin PS2 here is the link to the tables to find equivalent tire circumferences for different rims.
http://www.michelinman.com/specs/pil..._ps2/2958.html

Ideally you want the same diameter wheel/tires diameter as stock. You will change your effective gearing, suspension geometry, speedometer and odometer setting by getting out these parameters. Your revs per mile need to be the same (or very close) to the stock set up.

Front: 245/40ZR18 809 rev per mile
Rear: 265/35ZR18 814 rev per mile

BTW There are a lot of threads regarding this subject in the archives of this forum.

rbc55

with the propper fitment the 285/25/20 won't rub even when dropped as low as allowed.

rflow306

100% correct. 285/25/20 is the way to go.

Quick E63

Thanks... I used this site to figure it out.

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

V12Godspeed

I have 20's and all I can say is drive very careful, they make the car look so beautiful, I just can't explain it, lol!

Quick E63

Looks good I see Your still sporting that Euro motors plate.

What rear spoiler is that?

BenzoBoi

If you are runnin a 20 inch wheel and get a 35 series, the tire will hit the control arm bolt and will not work. That is the problem I had when I had my hre's back bout 3 years ago...I changed the tire size and it was fine down to a 30 series and it was all good...

TFKompressor

Front 245/30-20 and Rear 285/25-20 is the proper size because it maintains the oem rolling diameter. That is what i run on my Modulare 20x85 20x10s.

Jrocket

What brands carry 245/30-20 and Rear 285/25-20? Tire rack only has Yokohamas and Pirelli's? I thought there would be more companys offering tires in this size.

ROCKETW19

if you put a 25 series tire in the back you will bend a rim. 245/35 and 275/30 are both the same height. and what i recomend. you will have to trim a bolt in the front but no big deal. i honestly belive most run 285/25 because that is the only size certain tire companys make. so if you want PS2 witch most use, you have to run that size. i asked my tire guy what size works best then found a tire company that made that size.

jangy

I wouldn't even bother worying about tire brand or model if you are after a specific size like that. So what if it is a PS2 or a Conti? Performance isn't a factor, so go for full out looks.

Quick E63

I run Toyo Proxy's If you run 275-30's the diameter differance is over 3% which mean when your car is going 60 MPH your speedo will show 57.3.

285-25's are the right size to go with.

Jrocket

True,at those sizes performance isnt really a concern to me as much as cosmetics are.But there is only 2 models of tires at those sizes,neither really catch my eye on looks.

BMWEATR

P-ZEROS OR CONTIS MAKE YOUR CHOICE! my p-zeros suck! my cousin has the contis on his cls55 he likes them? I'm going to try out the conties next time around.(they are not the qaulity of conties that come stock on the car they are the better ones)

jangy

Got it.

Wesss

How about the front? I have 245/35/20's and I have shaved the bolt on the upper arm so there is no problems there. But after I lowered the car, I do get rubbing on the outside fender whenever I try to go up a driveway with the wheels turned at an angle. If the wheels are staight, there is no problem. So for now evertime I come to a driveway, I need to raise the suspension up via the airmatic. This works but I just don't want to have to keep raising and lowering the car everytime. I wanted to go with 255/30/20. The difference in diameter is like .7 smaller. Do you think I will have any rubbing issues? The wheels I have in front are 20x9 with 35 offset.

Jrocket

I dont think conti makes a 285-25/20.Im not a big fan of Contis anyway.,they seem to have alot of problems.

Jrocket

If a 245 rubs then Im bet the 255's will also.Either the car is really low or your offset is wrong.

Blue_Monster

I work at a custom wheel shop. Many people run 245/35 275/30 mostly because of the price difference. If money is no issue, go with 245,30 and 285/25, that is the suggested tire size for that car.

sang55

I dont have 20'' but I ran 19'' iforged daytona 19x8.5 & 19x10 ( 245/35) &(285/30) and they had NO problem at all . If you run 275 at the rear I think a little bit narrow .

Jrocket

Are you in sales?

Wesss

But do you think that going from a 35 to a 30 would be able to make a difference in rubbing? With the thinner sidewall my thought is that the 255 tire would work.

245/35 = 26.7 diam.
255/30 = 26 diam.

ROCKETW19

i have 245/35 and i think a 255 would fit. our fenders are already rolled givin you extra room. but my tire guy said it would rub so i went with the 245.