The overhaul in rules for 2026 will affect both powertrain and chassis design, with a near-50/50 split in power delivery from the internal combustion engine and the hybrid unit - which no longer includes the turbo-mounted MGU-H.
With the increased reliance on hybridisation, the powertrains will be heavier in 2026, although the chassis is expected to lose weight through being shorter and 10cm narrower than the current specification of cars. Aerodynamicists will also get to experiment with active aero to improve the on-track racing product.
This is expected to contribute to a weight saving of between 40-50kg, and Vowles believes that teams are going to struggle to hit the ultimate minimum weight limit - much like many of the teams had done at the start of the 2022 rules cycle.
"I think by 2026 [Williams will] be in a sensible place [with car weight]," Vowles explained in an exclusive interview with Motorsport.com, following an admission that Williams was losing over 0.4 seconds a lap with added weight.
"But even then, '26 has very interesting regulations at the moment that reward weight in a way that no other championship has, because it's such a low number. I don't believe anyone can hit that."
"That's on the side. But even beyond there, we need to make sure that we have a car that you can continually add downforce to in the wind tunnel at the right rate, so it's a competitive level. That's got to be what you want."
Explaining Williams' growth under his stewardship and his continuing desire to turn the team's fortunes around, Vowles reckons that the entire team remains ripe for improvement before it can even consider becoming a championship contender.
In addition to weight, Vowles has spoken of the need to modernise internal processes and investing in the materials aspect of the team, which will streamline the build of future cars produced at the Grove factory.
"There is not one area of this company that I am happy we are at the level required so we can fight for a championship. Not one," he added.
"That's a bold statement, but a truthful statement of it as well. Weight is the one that everyone out here will understand now why we're saying we're on the right path, but we've got a lot of things we need to address and fix.
"I've said from the beginning, we're open about it. We're going to be here and take you on the journey of what we're doing and why it's so difficult, and why Formula 1 is exceptional.
"But we will get there. Weight is just the one that's slapping us on the face today, but that's not the main issue."
