E-max 90 S Operator's Manual page 26

3.2 Tyres
The air pressure can be checked and adjusted if necessary at any service station.
Normal air pressure: 2.8 bar
If the tyres are worn or faulty, they may only be changed by the dealer.
Note:
3.3 Brakes
Squealing noises while braking indicate worn brake pads
or that there is a foreign object (e.g. a stone) in the brakes.
In this instance contact your dealer.
Too low air pressure or worn tyres may affect handling and range!
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