Abstract
The requirement for excellent field reliability in harsh environments and globally available service experience are the main drivers which are forcing customers to specify a drum brake versus a disc brake in many regions.
On the other hand faster service times, superior performance, better response behaviour, more stable performance characteristics (less fade) and mass volume cost effects have been the drivers for the market penetration of the air disc brake in the 1990s.
The demand for a truly zero drag brake with imbedded adjusters, the growing penetration of secondary and tertiary retardation systems with increase performance capabilities which lead to significant changes in load duty cycles. The availability of very sophisticated brake control systems able to eliminate historical drawbacks of the drum brakes raises the question of the potential for a reincarnation of a drum brake in Europe. A drum brake has an imbedded zero drag design which requires a significant effort to get and maintain a disc brake in a real zero drag condition. Integrated adjusters are proven to be well protected and surely life time capable.
The risk for the historical known fade disadvantage is shrinking by the introduction of multiple retardation systems on board of modern trucks and the advent of smart blended braking ECUs and algorithms.
This must be taken into account for the US if and when it switches to an Air disc brake or a Smart Drum brake and in Europe allows to ask the question about the substitution of an air disc brake or a remaining low volume drum brake production with a modern drum brake product coming from a supplier with economy of scale.
KEYWORDS Commercial vehicle, Drum brake, Forecast, Disc brake, Future trends