Like many (probably most) G owners, I swapped out the OE Pirelli Scorpion Zero A/S 275/50-R20's for an alternative tire. I mounted a set of Yokohama Geolandar A/T G015's, and after a year of everything Colorado could throw at them, I am very pleased with their performance. Inasmuch as flat tires always seem to occur at the worst possible time, I decided in anticipation of this coming winter to mount a fifth Geolandar on the spare. After removing the tire cover so that the tire dealer wouldn't have to mess with it, I was stunned to find that the OE spare tire is a Continental Cross Contact UHP 265/50-R20 111V, and not a matching OE Pirelli. WTF???? MB makes $150,000 vehicles with an odd-ball spare tire? Even my wife's Rubicon costing 1/3 as much came with five matching tires. I thought at first this must have been an assembly line screw-up, but there's a yellow sticker on the alloy wheel (guess I should consider myself lucky the wheel isn't a piece of stamped steel from JCWhitney) indicating "MAX 50 MPH". I can only guess what could happen cruising down the highway at 50 MPH with mismatched diameter/brand/construction rear tires when the Lane Keeping Assist kicks in, or what might be left of the drive train after off-roading with locked differentials. This Continental tire retails for about the same as the Pirelli, and is listed as OE for Chrysler/Dodge/Jeep. So is MB surreptitiously disposing of inventory leftovers on unsuspecting G buyers? For the cost of another Geolandar, it's not worth my time to complain to the dealer or to MB. I can now build my granddaughter another swing, this time with a brand new tire. I'm interested in what other G owners have found hidden beneath their spare tire covers. Also, has anyone run the OE Pirellli's in mud or snow (they are marked "M+S" on the sidewall, but the tread looks as if it would struggle in 1/2" of standing water)? BTW, the spare tire cover ring is nearly at its maximum span with the Continental spare, and the Yokohama being 4.4" greater in diameter will require a modification of the clasp lock. Has anyone else dealt with this?

 

All five of my tires/wheels match on my '20 G550. Do't understand that they would hav a speed limit on a full size spare albeit it is a different brand tire.

 

The reason for the Continental is due to the cover not being able to go over larger tires. It also seems that tire is used on the GLS (and likely GLE)

Also, I assume MB would have tested the spare with the safety systems which is likely why there is a top speed limit (due to the difference in rolling diameter between the tires.)

Now why isn't the cover just larger? Maybe it has something to do with the fact that the spare covers the rear window and if it got larger it would block too much of the window since it would need to likely shift up to prevent it from blocking the rear camera.

 

The circumference difference between the Pirelli and Continental is only 1.2", which the cover ring will accommodate. The diameter difference is only 0.4" - hardly enough to interfere with either the camera or rear window. The spare tire mount is where I'd place the flat Pirelli after take-off. The speed limit sticker, however, is definitely because of tire size/brand/construction mismatch with the Pirelli

 

The spare that came with my 2020 G550 was the same as the other 4 wheels/tires, which were the Black AMG 20" wheels albeit I sold those so the spare remains. All spares are 20" as far as I know on G63s.