Joined: Dec 2004
Posts: 12,560
Likes: 799
From: Middle of da Mitten
Bikes: Trek 7500, RANS V-Rex, Optima Baron, Velokraft NoCom, M-5 Carbon Highracer, Bacchetta Quattro, Catrike Speed
Using a chain tube might reduce the amount of dirt a chain picks up, expecially if it's used where a chain might otherwise be running in wheel spray. But mostly chain tubes are used to protect the frame or the rider's clothes, and occasionally to aid with routing. Unless you completely enclose the chain, it'll still pick up road dirt.