Just to start out, for the search and FAQ ****'s, I did do a search and read the pertaining FAQ's and all applied to the SE and I am looking for info on a GLE. I would like to upgrade the tires and still keep the stock GLE rims. I know very little about tires so please bear with me. Am I correct in saying the first # in the tire size is the width, the second # is the sidewall height? I would like to get either the Continental Conti Extreme Contact or the Pirelli Pzero Nero M&S. What is the largest tire I can safely upgrade to? With the stock tire being 215/55-17, could I use a 215/50-17, or a 215/45WR-17? What is the WR? How about using the same size tire that is on the SE, 225/50-17? Are the SE and GLE rims the same size? Sorry for the ignorance, just need some help. I have seen many threads on the Continental tires and it seems people are pleased with them. I have not seen anything on the Pirelli's. Does anyone have any information on the Pirellis? How do they compair to the Contis? Thanks.

 

That's funny

Now, to answer some questions.

Am I correct in saying the first # in the tire size is the width? Yes

the second # is the sidewall height? Yes

What is the largest tire I can safely upgrade to? According to Tirerack.com, largest and safest upgrade size would be 235/50-17

could I use a 215/50-17, or a 215/45WR-17? Probably. Use this tire size calculator to compare your stock size to alternate sizes. As long as you're within 3% difference of stock, it's all good.

What is the WR? the W indicates the tire’s 168 mph maximum speed.

Go Here for some general info on tire sizing

 

I'm not going to respond to the "safely" question because there are too many variables and opinions on "what could, should and will fit" versus what is practical, legal (in spec) and most importantly, meets your driving needs. One thing I will say, honestly assess your expectations for the tire (performance, tread wear, aesthetics, etc.) and buy what you need as opposed to what you are told "will fit." That said, I dug pretty deep researching this topic and made my final a purchase a few days ago for my GLE.

For my objectives, I settled on a 225/50-17 high-performance tire on my 02' GLE giving up a little ride-quality for better handling and performance. I also stayed very close to the OEM overall diameter spec when comparing the tire sizes. Here are the differences to give you an idea:

EL42: 300 A A, 1433lbs max, meas. rim 7", section width 8.9" overall 26.3"
New: 400 AA A, 1477lbs max, meas. rim 7", section width 9.0" overall 26.1"

Also, GLE Rims are not the exact same size as SE models (at least for 02's). They are both 17x7 JJs but the offset is different (check your OM for the specifics). While a minor difference it is a "difference" nonetheless and therefore a has an impact. Noticeable? I don't know. My opinion is really of no value because I am biased towards the decision/purchase I made but I can say I have 125+ miles on my new treads in wet and dry conditions and they are exceeding my expectations (after "break-in" I will drive them hard to test). Although this tire is not one of the mfgrs. you are considering here are a couple of pics of what a 225/50 looks like on stock 02' GLE rims @ 32psi after being mounted: