johnc510

I'm in the market for 20" wheels and called a local wheel shop. He suggested I go with 235/35/20 tires for the fronts (I'm considering the Vossen CV5 wheels). I told him my stocks are 245 wide, why would I want to go 10mm narrower? Anyhow, he says since my stock wheels are 18", 245 width is fine and that with the 20" wheels, the 245 tires would rub on the strut mount since my car has the spring-based suspension (as opposed to air ride).

I don't get it. Doesn't 245mm tire width = 245mm tire width, regardless of the size of the rim? Given that, why would 245mm 20" rub when 245mm 18" does not rub?

I need a second opinion here. Better yet, I'm sure many of you are running 245mm 20" in the front. Thoughts?

Tjdehya

Pm this guy he will answer your questions.
diego@vossen
https://mbworld.org/forums/members/2...go-vossen.html

brauhaus313

A 245/30/20 is taller than a 245/40/18, but you still shouldn't have a problem if you run the appropriate offset. I run 20x8.5" et35mm up front and don't rub on anything.

While your tire guy isn't right, I wouldn't blame him for being overly cautious. For my next set of tires, I might go with 235/35/20 just for some extra ride comfort.

bigigg

^ Exactly.. 245 on a 20" is 1" closer to the spring pad than a 245 on a 18".. with correct offset you should be fine..

threeMBs

Its a typo above. Its .1" (1/10") closer not 1" closer.

Also, "tire guy" is wrong and right at the same time. 245/30-20 has zero chance of rubbing (with correct offset range for W212 - for 8.5" wide wheel it is from et35 to stock et48). However, he's correct to suggest 235/35-20, even if for wrong reasons. However, with 235/35-20 offset is critical, otherwise they will rub.

bigigg

What I meant was the radius of the tire.. 2" overall.. soo that brings it 1" closer to spring pad.

Three, I need your expertise on this one.. 245/30/20 9" 35et, and 285/25/20 10" 42et. what ya think

threeMBs

You lost me there.

Front - no issues for stock, but since you're lowered - then I'm not sure.

Next week I'll try 20x10 et42 with 275/30-20 rear. If it will stick out (hope not since it'll be very close), then 285/25 will even more and may rub since you're lowered. Also, many tires in that size require 10.5" wide wheel. Will let you know then.

Why are you downsizing tires' profile from 235/35 & 275/30? I thought you had no issues even lowered (of course I'm not).

bigigg

I was on 275/30/20 40et rear.. you will have no issues at all with 42et..the rim is flush with fender and tire has slight stretch.(thats y i think a 285 will be fine) I sold my set of wheels looking to go to a 9" front not 8.5.. I had some room to spare with a 235/35 35et front (i think a 285 will be fine)

threeMBs

Well, you would be loosing almost 1/2" of sidewall "buffer" at rear and over 1/3" at front. Not insignificant considering your general area's roads. Of course will not make that much difference since 20s is 20s, but every little bit helps.

bigigg

I agree, i'll most likely stick with 235/275

RobbieRob

I went with the 235x35x20 and 275x30x20 on 20x8.5 and 20x9.5 with both having -35 offset. I chose those tire sizes for 2 reasons: 1-extra sidewall(which isn't much) 2-I planned on lowering and didn't want to rub when lowered down. I am pretty slammed, 1.68" front and 1.79" rear(according to my renntech v3) and only get a slight rub on off camber driveway entrances. Since I have a 550 with the air ride, I have some room to raise the car if needed, so I can run lower then usual when wanted or just hit 2 buttons to raise the car about 3/4"(comfort) or about 2"(raise mode). When I was about to purchase these tires(especially the fronts),I was worried about that 235 size being to small, but I have to say the car handles just as good and the difference in width is minimal. Good Luck