Ferrari driver Sebastian Vettel completed the first test of the 2017 Pirelli F1 tire at Ferrari’s Fiorano test track Monday, with Haas F1’s Esteban Guttierrez taking over the reigns Tuesday to complete the two-day demo.

The tires, which are 60mm wider in the front (245mm to 305mm) and 80mm wider in the rear (325 to 405mm), were fitted to a slightly modified version of the Ferrari SF15-T 2015 F1 car. On Monday, Vettel first completed laps in slick tires before switching to an intermediate compound as an artificial watering system dampened the Fiorano circuit.

Guttierrez’s tire test was much the same, with the Mexican driver first completing some laps in dry weather tires before switching to a wet weather compound. Red Bull will be the first team to complete a major test of the dry weather compound when they demo the rubber at Mugello Wednesday and Thursday.

In addition to the wider tires, the SF15-H was also fitted with a lower, wider rear wing and other modifications designed to simulate the aerodynamics changes for 2017.