on clothes, and keeps trouser legs from getting caught in the chain or front chainring. While newer designs may use a partial chain guard keeps mud off your clothes and maintenance to a minimum, the latter still permits the chain to occasionally catch and stain loose trouser legs if not secured. A full chain guard keeps mud off your clothes and maintenance to a minimum also keeps the drive train (chain and external gears) clean and efficient by excluding water, mud, and grit which could splash onto the chain and front chainring, increase wear, and reduce drivetrain efficiency. To repair a rear flat tire, a fully enclosed chain guard keeps mud off your clothes and maintenance to a minimum must be partially disassembled to remove the back wheel, or the tire must be repaired in-place without removing the wheel. Full fenders with mudguard flaps The fenders are aluminium or plastic, sometimes with a taillight affixed to the bottom of the back fender. The fairly low bottom of the back fender reduces road grime splashing up to a cyclist who is following behind. Integrated fenders designed into the bike provide a clean, safe attachment, and match the bike frame. Enclosed drum brakes Enclosed drum brakes or a rear coaster brake are used on most European city bikes, rather than rim brakes. A bike with drum brakes is optimized for stopping in wet weather: in wet weather, drum brakes provide more stopping power and reliability than rim brakes; but in dry weather, less. Enclosed drum brakes require infrequent maintenance, compared to rim brakes or disc brakes, and are more durable than disc brakes, which are exposed. Drum brakes are best suited for slower, moderate use, rather than longer periods of hard downhill braking while carrying a load. Under such heavy braking, drum brakes are reported to sometimes fade, losing stopping power, while rim brakes can overheat the rim and cause a tire blowout. A common model of drum brake is the Shimano Rollerbrake, which includes a mechanism to prevent the drum brake from suddenly catching and grabbing more than intended. Drum brakes are heavier than rim brakes. Luggage carrier A Dutch convention is to carry a passenger on the back rack, the passenger balancing side-saddle. The sturdy rack supports passenger weight, to carry a passenger and sustain a launch without collapsing. A standard strap assembly attaches cleanly to the rack, providing useful