Downsizing 20" wheels to 19" wheels
 

Hey all,

I'm looking to get more opinions. I currently ride on 2014 E350 sport sedan and upsized to 20" wheels with 235/35 up front at 32 ET and 275/30 in rear with 35 ET (rubbing on bumps). Driving in this for a year a half led to me needing to fix my wheels more times than I can count, not to mention tires getting worn out fairly quick, despite the great looks.

Anyways, I'm thinking downsizing to 19" wheels will add more protection. However I am not confident in my setup. I went with Discount Tire advice and these are the current specs for new setup: Mandrus Estrella wheels at 32 ET & 8.5" wheel all around with 245/40 Falken Pro G5 Sport A/S tires.

I'm switching to a square setup to get more mileage out of my tires and downsizing diameter to add ability to protect the wheels more. I also want to get it right and make sure I don't have any rubbing this time around.

Anyone care to share their thoughts? I have only put down a deposit so far, so I can change these specs need be. Thanks.

19 inch wheels can still scrape on most curbs. What tires do you use? Using a tire with a better more protective Sidewall setup helps greatly. I use Pirelli PZeros Neros on my car (whcih is only 17 inch) but also on my Camaro with 20 inch wheels, and the sidewall setup is designed to stick out a little further than the wheel to protect it. You can still damage it if you hit hard enough of course, But you are safer from gentle rubs. Just a thought.

It is not the wheels that will scrape, but the tires, so getting right combination of diameter and width is crucial.
Doesn't look like you are concern about rpm as usually that is the first parameter I would check as I like the speedo and odometer to be accurate.
That said, I read that even 18" rims on those cars do get lot of repairs. My W212 come on 17" and I am actually concerning switching to 16 for better comfort as that is what I have on W211.
Obviously taller sidewalls add to fishtailing, so it is compromise.

True RPM is not at the top of my list for concerns. Obviously I wouldn't want it to be off too much but I will look into it as well.

I have a 2016 e350 4Matic with the 18" AMG Wheels on it and the original Conti tires on it as I just bought it recently as a CPO with about 9300 miles on it. I am used to driving cars with very low profile tires and big wheels on the terrible, pot hole ridden roads of Long Island and NYC and I can absolutely vouch that with the sport suspension equipped these wheels are very easy to damage. I hit one pot hole that on my last car which had 20" wheels and 235/35 tires on it wouldn't have done anything and I got a bubble in the sidewall of the tire and a slight bend at the contact point. I'm regretting not taking the wheel/tire repair package MB offered at time of sale lol.

I do think some of the issue in my case has to do with the Conti tires not being all that great to start with but that shouldn't happen after 1 pot hole hit at less than 25mph.

ET32 on a 8.5 seems wrong. Mine has a stock square setup with 8.5 @ ET48.

Try this calculator to see whether things will fit or have issues:
http://www.rimsntires.com/specspro.jsp

these modern cars all have very high offsets requirements. If you put a wheel on them that is meant for older mercedes (w210/w211) with sub-35 ET then you are going to have rubbing on fender with correctly sized tires.

I started out with 20x9.5 ET45 front & rear on 245/30/20 tires, with the airmatic lowered 2" from stock. It looked great, but when you lower airmatic the ride becomes much stiffer, so I raised it back up about 1.25" and used larger tires. Second set I tried was 265/30/20 Michelin Super Sports all around. That fit great, no rubbing but still not as tall as I wanted them. So I the round of tires after that I tried 255/35/20 front and 285/30/20 in the rear. The rear fit no problem, ironically the the 285/30 even fit just fine in the front, but the 255/35 did not clear the airmatic strut perch, too tall. I didn't want it rubbing on the airmatic boot, so I stuck another set of 265/30's on the front.

Here is how much clearance the 265/30 has with the front airmatic strut. If you have steel springs, a 255/35 will fit just fine, I know other forum members have that size.
https://cimg0.ibsrv.net/gimg/www.mbw...ed209fc938.jpg

Absolutely not. 255/35-20 won't fit any W212, especially steel (non-airmatic). 245/35-20 clears only airmatic, it won't clear steel without some "work" on that perch. The tallest tire clearing steel springs on w212 is 235/35-20, and even that requires 30s offset.

Any thoughts on 245/40-19's?

Most of 245/40-19 tires are 26.7" and is just under 26.8" of 245/35-20. There are some (one or two) 26.6" (there's a slight variation by manufacturers) 245/40-19 tires which may just "make" it. Any 235/40-19 will fit for sure.

So for 19x8.5 wheel best tire size is 235/40 or 255/35. This is great except I cannot find a tire which has these specs and meets 97 load rating. Discount Tire of course will not install unless meeting load rating. It is pretty ridiculous how hard difficult this is.

According to the calculator link I posted above, If I wanted to go from stock 18x8.5 to 19x8.5, then the new tires closest in dimensions would be 245/35/19. Searching Discount Tire site, I see those all have a load index of 93, and according to their own chart, that is a weight capacity of 1433 lbs PER TIRE! More than enough to support an E Class. I don't know what kind of monkeys you're dealing with at your store. Tell them to put the darn car on a set of scales, I am confident that not one corner will even come close to 1433lbs. Where did they come up with the 97 load index? I see that my current 245/40/18 are a load index of 97, but that's only 176 lbs more per tire, hardly much of a difference. If they won't do it for you, just buy the tires somewhere else.

If you're switching to 19 to avoid flats and fixing wheels, keep going. I have 17 inch stock wheels, 245/45/17 and I still get flats and bent wheels. Not as often as the 18 on my W211 though.
You'd have to go to 50 series or higher to avoid bent/cracked rims and flat tires, but the best you could probably do is the 45 on the 17's. Low profile tires are just asking for it.

Where do you live, somewhere off-road? I haven't had a problem with my stock 18s, other than getting too close to a couple of hard curbs.

In the city. Lots of potholes now from freeze/thaws and snow.

Choosing tires is always compromise.
I have W211 on 16 and W212 on 17.
When changing the car, the "boating" effect on 16" wheels is pretty noticeable, but then the car takes road imperfections with only acoustic sound
We do have good roads, but on 17" wheels - each street cover feels like somebody hit bumper with sledge hammer.
Than latest purchase on 18" wheels has 2 AMG rims crack.

I am just striking the balance between looks and ride functionality. To me 19" is going to be that perfect balance. I may still need to fix wheels every so often but I do not object to it. 20 inch wheels however, was just far too frequent to do. In my 2 years with them I had to fix my wheels about 8 times.

So you hope that with 19" you will have to fix them only 6 times every 2 years?

Of course not but 6 is an arbitrary value you are throwing out there. 1 time a year is probably my comfort level.

On another note I read my door placard and it doesn't specify a specific load rating each tire needs to meet. It gives me the gross weight I have to meet for each axle. I spoke with Tirerack and although my original models came at 97 XL, if the tires I choose can meet the GAWR then they should be able to be installed. I go back to DIscount this weekend and we'll see what they have to say about it. They initially installed 245/40 and right now the fronts rub badly.

Well that may be 17 inch tires. Two bent rims in 2 years, one flat. In 4 years on the 18 inch set of wheels, 3 bent rims, one crack rim and at least 4+ flat tires, but one of those was fixed with a plug. The 18 just got another tire slowly leaking air, going to fun to see if it's a flat or another cracked rim. Seems like anything 45 and under is basically asking for flats, bent/cracked rims.

Where are you rubbing with 19x8.5 and 245/40? I've been eyeing a set of 19s for sale taken off a new E400. They are 19x8, with 245/40. Ideally I would want 245/35 tires, but the tires are included and brand new. Just wondering if your current issue is an offset issue?

I am rubbing badly on the front. I have a square setup and 245/40 is just too tall of a tire for 19" diameter. It is not an offset issue because my wheels are not poking out the fender.

OP, I told you 245/40-19 will most likely rub upfront. When I suggested 235/40-19, you were concerned regarding load (even though you were on 235/35-20 with 92 load before). 235/40-19 XL tires have more than enough load of 96 for W212. Tallest 19" sidewall that fits front of W212 is 235/40, the most proper tire though is 255/35-19, OEM size on E63, also with load of 96. If idiots at Discounttire won't install them, there are many other places who will, including your MB dealer.