Tyres.co.uk has Michelin Pilot Sport 5 energy and Bridgestone Turanza 6 tyres for various models of the Mercedes GLS-Class. These include the sizes 275/50 R20 113Y XL and 275/50 R20 113W XL respectively for X167 GLS 450 d variant that has 20-inch wheels. Please confirm the registration, load index, speed rating and XL specification before purchase.
Mercedes GLS-Class tyre sizes can be found on the tyre pressure info placard located behind the fuel filler flap. This states the manufacturer approved wheel and tyre combination. The size of the tyre is also printed on the sidewall of the tyre but to be specify the front and rear, load index and speed rating it is advisable to check the fuel flap info placard and the info booklet.
GLS-Class vehicles do not always require 4 new tyres. However, all 4MATIC and 4MATIC+ variants must have corresponding same make and type and correct size on both axels. Replace tyres in pairs per axle; for square fitments, put a new pair on the rear axle. Staggered fitments must retain their designated front and rear sizes.