I have a recently purchased (slightly used) BF Metro. Me and this bike don't get along. The more obvious problem is that the chain keeps falling off the chainring every time I get up any speed. I've encountered this problem with a commuter I had set up with just a single chain ring up front. In that case I cured it by putting a chain ring guard so the chain couldn't pop off. I have never seen a guard for a chainring that big as is on the BF. Nor is there anywhere to attach it on this chainring. I'm beginning to regret not having bought a Dahon Vitesse. Any suggestions other than converting the rear hub to an internal 7 spd. Nexus or making my kid drop out of college so I can afford to buy a Rohloff?