The "auto parts" makers who supply parts for new vehicles, or do partial or even full assembly on contract, are subject to the cyclical market for new vehicles, BUT, every new vehicle become an aging vehicle which is likely to need replacement parts, increasingly over time. So, the idea goes that there is a lagged response for the demand for replacement parts, or accessories, and associated services. Hence, a longer term investor may be  interested in firms that respond to those sorts of ongoing demands.  Of course the complexity of the demand for parts and any given firm's prospects for selling replacement part or accessories will depend on many factors. One concept working for the down-the-road replacement parts maker is the Marginal Value Product (or Utility) "trap"; an aging vehicle is often repaired rather than replaced or junked, even at considerable expense because a new vehicle is a much larger outlay. Priced a cam shaft kit lately? Or a replacement side mirror?