I have a 2001 E320 with original wheels (Original Equipment Size: 215/55-16 according to Tirerack.com). I am interested in buying these but I'm unsure what tire size to use to avoid changing any gear ratios or messing up the speedometer. I obviously don't know anything about this so all help is greatly appreciated. Thanks!

 

Read up on tires and wheels first at tirerack and
http://www.1010tires.com/TireSizeCal...?action=submit
a 235/45/17 will be dead on with the oem diameter.
tirerack or discount tire have great selections of 17's with the correct offset and they supply the proper lugs
Tirerack has a great new viewer that lets you see how the wheels would look like on your model
Those look like cheap painted wheels.
They claim they are an E55 stagger and E55 stagger is not a 17 in rim.I don't see lugs listed so you would be out spending more money on hardware.
Avoid buying car parts off of ebay.
ohlord
w210 section of benzworld.org diy section has a nice areea about wheels and tires

 

On my 1999 E320 the tire size (factory) is 215-55-16. Lets say you went to a 215-60-16 which is about 1" bigger in diameter, your speedo will be off 3mph +/-. Also, if you don't keep the front size tire the same as the back tire it causes problems with the cruise control as the front and back ratios are different. What ever size you choose, the fronts and back need to be the same size. Stick with the 215-55-16 .
Larry

 

Larry he's plus sizing to a 17 inch rim.
A 235/45/17 is the same diameter as a 215/55/16 just wider and lower profile.
He could go to an 18in if he wanted
E55: 18 x 8” ET31 front, 18 x 9” ET35 rear
Tires 245/40ZR18 front, 275/35ZR18 rear
and still be within the 3% allowable difference of error
he would need to roll the fender lips and get it aligned
if he dropped the suspension.But there is no need to do that with
17's and get a little more rubber on the road
while keeping his esp,abs,cruise control and speedometer
all functioning properly.
There are even members with 19's and 20's that if plus sized
properly have no problems ,other then harsh rise quality and if they spend the money
to get the camber set up they even have good tire life.
17's have none of those concerns.
You may also want to read up on tire sizing and
rim fitments ,before passing out erroneous information.
ohlord
with the proper offset and a little
massaging of the rear wheel wells people have gone
all the way to 295/30/18 on the rears.