Just in case anyone else is looking for the widest tread for the 9" AMG rim, I just installed a set of 275/45/20 Conti Extreme Contact DWS tires on my 2013 ML550. The original Conti Cross Contact tires actually impressed me with the ride, handling, and wear, but at 27,000 miles a flat in the middle of the Ford Shale forced me to take a hard look at the tread left. Since it was getting close to the "hydroplaning" threshold, and I tend to drive very fast in the monsoon season here in Houston, I decided to forego the few thousand miles remaining and replace them.

My research in preparation for the replacement focused on finding the widest tread possible. For anything that was recommended for the 9" rim, the tread width was about 9". Going to a 295/45 would give me just over 10", but a 9 1/2 rim was the minimum recommended. The 305/50 would also give me a solid 10", but would raise the truck almost 1 1/2" but with a 9" rim. I've put taller tires on my MLs before, but did notice the handling was slightly degraded. So, when I found the DWS in 275/45 had a 10" tread on 9" rims, and was reviewed as an excellent rain tire, my search was over.

After only a few days and no heavy downpours, I can only say the tires look very good. The wheelwell is definitely fuller than before. The ride and handling is better than before (although after 27,000 miles, the original tires would have been degraded to some extent). The height increase is about 1/4" or less, so it is not noticeable. Discount Tire had to ship in a set (virtually no one carries the 20" tires in stock, I found), but it only took two days. The price of about $250 was about the same as Tire Rack and other stores, so I was $1300+ out the door with a replacement against future sidewall rips should I venture out onto the Ford Shale again. So far, so good.

 

Oh, and I installed the full-time illuminated Star for added safety. There are some mighty big deer on the Ford Shale.

 

Thread width is meaningless when looking at the widest tire/wheel combination possible. The correct parameter is the section width, which is 10.7" on 9" wheel for DWS. It is also identical to Kumho STX (which costs almost full 50% less or almost $500) and almost identical to Yokohama Parada (an excellent SUV tire with 10.6" on 9" with savings of $400 as well). But I do agree overall that 275/45-20 is the tire to get for ML550 (instead of stock's 265 Contis or Pirellis).

 

Does the illuminated Star repel deer?

 

Naw, but they do stop dead in their tracks, and stare in awe.

 

I did look at a variety of tires including the Parada, but it was the unrelenting praise of the DWS rain handling capabilities that made the difference. Still, I would have stuck 295/45s on the 9" rims if I had the least bit of encouragement. Size does matter! Especially, if you're sporting a brightly lit Star on your grill. Keeps the laughing to a minimum.

 

Agree again. 295 (45-20" or 40-21") would be an ideal tire for ML550. Of course not on a stock 9" wide wheel. GL550 wheels/tires would be ideal with a bit higher offsets.