M545 is a non-series chainset – it doesn’t belong to any of Shimano’s groupsets. But constructionally, it’s very similar to Deore. The arms look almost identical from the outside, with a swoopy, low-proﬁle design.
Round the back, there are smaller weight-saving hollows. The M545 is built for strength, and Shimano have gone for the simple approach of lots of material. There are steel inserts at the pedal eyes, and you get pedal washers.
Chainrings are a well-chosen 22/36-tooth combination that gives a versatile spread of gears. Both rings are steel, with notably deep teeth on the inner, and protected by a fat polycarbonate bashguard. Weight (1,127g) is reasonable for the price.