Kimi Antonelli sidelined as George Russell drives W15 mule

During the gap between Miami and Imola, Mercedes slipped into Silverstone for a two-day tyre session that broke from tradition in two ways: it was closed to the public, and it unfolded on the 2.63-kilometre National layout rather than the expansive Grand Prix loop.



The shortened course links Copse to the Wellington Straight via a right-hand flick at Maggots, excising Abbey, the Arena complex and the high-speed run through Stowe, Club and Vale. That tweak allowed Pirelli engineers to log rapid-fire laps while focusing on traction zones and moderate-speed load changes critical to wet-weather compounds.



Russell Piles Up Laps in the W15 Mule



George Russell took sole driving duties in a mule car derived from last year’s W15, amassing 80 tours—or 481 kilometres—across the test. Day 1 targeted baseline running on slicks as reference, while Day 2 saw Silverstone’s sprinkler system douse the surface to simulate standing water.



Mercedes mechanics cycled through multiple iterations of prototype extreme-wet and intermediate tyres, recording real-time carcass temperatures, aquaplaning thresholds and driver feedback.







The session’s intensity mirrored a grand-prix Friday: fast out-laps, constant in-garage checks, then successive short stints to isolate each construction’s strengths.



Pirelli Zeroes In on 2026 Wet Compounds



Pirelli’s motorsport director Mario Isola hailed the exercise as pivotal in validating a rain-tyre roadmap that began with controlled trials at Paul Ricard in January. “It was a very useful test, because it allowed us to gather valuable insights on our rain tyres, to add to those acquired in Paul Ricard back in January,” he said.



“With the intermediates we were able to confirm that the on-track development matches our expectations, while the results with the full wets were inconclusive and will need to now be thoroughly analysed in the coming days to continue refining the product for next season.”



Why the National Layout?



Although shorter, Silverstone National compresses three braking events and two long acceleration zones into a 65-second lap, enabling tyre suppliers to clock data points at almost double the frequency of the full 5.9-kilometre circuit.



The high-energy Copse entry stresses the outer shoulder, while the cut-through toward Wellington mimics intermediate-speed corners found on many 2026 calendar venues. For Mercedes, the configuration also limited mileage on a mule chassis not designed to carry this season’s complex aero kit, reducing wear on non-critical parts while delivering the surface loads Pirelli needed.



Barcelona Awaits the Next Milestone



The wet-tyre programme continues on 3–4 June at the Circuit de Barcelona-Catalunya—immediately after the Spanish Grand Prix—where Mercedes will reunite with Racing Bulls for another controlled spray test. Engineers plan to refine groove depths, belt angles and tread stiffness using the Silverstone data as a baseline.



By mid-summer, Pirelli hopes to lock in specifications for FIA approval so that teams can begin 2026 chassis simulations with realistic grip models.



Bigger Picture for Mercedes



For the Brackley squad, the outing served double duty: aiding Pirelli while giving Russell valuable seat time with experimental suspension settings aimed at improving slow-speed traction—an Achilles heel of the current W16.



It also offered a low-pressure environment for pit-wall staff to rehearse new data-analysis protocols introduced by technical director James Allison. Though lap times were irrelevant, insiders reported Russell felt balance gains in longitudinal grip that should translate to Imola’s heavy-braking chicanes.




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Takeaway



A seemingly modest switch to Silverstone’s National circuit produced a trove of information for Pirelli’s 2026 wet-tyre push and allowed Mercedes to experiment away from prying eyes.



With additional tests looming in Barcelona and Monza later in the year, the tyre supplier now has the comparative data it needs to fine-tune compounds that must perform in ever-stricter sustainability and safety windows.



For Mercedes, every kilometre of hybrid mule running could pay dividends as it chases runaway leader McLaren—and as Russell, sitting fourth in the standings, looks to springboard into the European summer with renewed confidence.
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