How in the world did Mercedes-specific tires end up on a high-performance Ford SUV, then? There is an explanation, and it comes from Ford Performance chief engineer Ed Krenz. He said that Ford made the decision to add a grippy summer tire to the order sheet late in the vehicle's development. Up until that point, the Explorer ST only had Pirelli all season tires. Without time to develop a specific tire with Michelin or any other tire manufacturer, Ford went shopping for a summer tire with the same specs that fit the 21-inch wheel they were already using. Turns out, the only option was this Mercedes tire, which is a perfect fit to the Explorer's 275/45R-21 size.
Ford is using a square tire setup — 275-section-width tires at all four corners — while Mercedes has a staggered setup. These tires on the Ford are equivalent to the front tires on the GLE43 Coupe. The Mercedes has wider tires in the rear, and can also be specced with 22-inch wheels.
There's nothing especially bad about using Mercedes tires on a similarly-sized Ford, but manufacturers work closely with tire companies to develop vehicle-specific tires for a reason. Everything about the tire can be optimized and dialed in to suit that vehicle, and that hasn't been done for the 2020 Explorer ST. Still, we're happy to have a summer tire option to give the big performance SUV more grip and better steering. Check back soon to see our driving impressions of the new Explorer, summer tires and all.