Purcell Tire & Service in Billings, MT

All-season tires are a compromise that works in mild winters and struggles in severe ones, because the rubber compound hardens as the temperature drops. Montana winters are the case the compromise was not designed for.

A winter set is a different class of tire rather than a marginal upgrade, and whether you need one depends on how much you drive in it and where. Ask the store what people in this area actually run; it is a more useful answer than a general rule.

For a fleet, the winter questions are pressure and alignment rather than tread pattern. Cold air lowers pressure, an under-inflated tire runs hot and wears badly, and a unit out of alignment on an icy road is working against itself.

The other seasonal item worth naming. Cooling system service matters in winter as much as in summer: coolant that has lost its protection is coolant that can freeze, and the heater that keeps a cab habitable runs off the same system.

If the cabin heat has dropped off, that is usually a cooling system symptom rather than a heater fault, and it is worth dealing with before the weather does it for you.

• Belgrade, MT, 246 Briar Pl #2, (406) 388-2710. Six services for trucks, fleets and off-highway equipment, with no vehicle repair.
• Outside Montana, the nearest Purcell locations are in Idaho and Utah, which is also where casings go for retreading.

See the Montana locations page.