What size is the arbor on the grinder? Some companies use the same model number for variants of the same tool. The arbor dimensions might vary depending on what market the tool is being sold in. When I looked up the specs, the Metabo website gave the grinding wheel specs as,
Grinding wheels (Ø x thickness x bore) 7 x 1 x 1 mm
I tend to doubt the grinding wheel is 7mm in diameter. If the grinder uses wheels that are 1 inch wide, 7 inches in diameter, with a 1 inch arbor, which would make more sense, then the wire wheel you use should probably be 1 inch or less wide, 7 inches in diameter, with a bore that's at least 1 inch. Some wire wheels will have a larger bore diameter, in which case you'll need to use arbor adapters. Companies such as Pferd and Norton that manufacture wire wheels also offer arbor adapters. Any good industrial supply that sells the wheels should also have the adapters, this includes companies like McMaster-Carr and Grainger, and MSC. You can probably get away with using a smaller diameter wheel but it won't be as safe to use.
