Formula 1 will make the switch to 18-inch wheels from the 2021 season, as well as placing a ban on tyre blankets.

On Thursday, the FIA issued an invitation to tender for the sole tyre supply contract from 2020 until 2023 seasons, with submissions from interested parties required by the end of August.

Pirelli has been F1’s sole tyre supplier since 2011 after taking over from Bridgestone, but is out of contract at the end of next season.

German GP Records

In the technical information included in the invitation to tender, the FIA confirmed that F1 will switch to 18-inch wheel rims from 2021. The change has been considered for some time, with Pirelli conducting tests using 18-inch wheels in 2014, but the sport has since retained the existing 13-inch design. The front tyres from 2021 will also reduce from 305 mm to 270 mm in diameter from 2021. The rear tyres will remain 405 mm.

Moving to 18-inch wheels from 2021 and banning tyre blankets are moves “in keeping with the overall objectives for the evolution of the Formula 1 Technical Regulations in 2021, which aim (amongst other things) to improve the racing spectacle,” as per the FIA.

However, with the tender starting from 2020 and the technical changes only set to come into force from 2021, any new supplier would therefore have to produce two sizes of tyre were it to take over from Pirelli.

Under the new tender, the supplier will still be required to offer teams three compounds for each race weekend - a hard, medium, and soft - with the FIA offering guidelines for the pace differential and level of degradation involved.

The FIA is aiming for the medium-compound tyre to be 1.2 seconds per lap quicker than the hard compound, with the soft tyre being a further second per lap quicker

Via the degradation guidelines, the FIA stressed that any strategy using the soft tyre should result in a two-stop strategy, with a one-stop only possible by using the medium and hard compounds only.

Despite the ban on tyre blankets, the compounds should still offer “safe performance when leaving the pits cold,” while a special low temperature compound will be provided for winter testing.