I'm happy to help. For whatever it's worth, if you watch "the movie", the Marin guys seemed to consider a
Bomber as a singlespeed coaster bike with no other brakes, a
Klunker was a singlespeed coaster bike with some kind of auxiliary front hand brake, and a
Hybrid was a multispeed conversion with derailer(s) and front/rear hand brakes. Alan Bonds's site,
www.clunkers.net, seems to suggest a similar system of nomenclature, although he doesn't offer any cut-n-dry definitions on Klunker taxonomy. As I see it, any time you're riding trails with a frame designed for cruising, but in
any way modified for off-road use, you're klunking, on a klunker. The inevitable discussion about the equipment you're running will fill in any blanks about brakes, drivetrain, etc...
I think Sturmey-Archer
is worried about liability, and also good ol' fashioned common sense, when they say the x-fd is intended for road use only. A drum certainly isn't a disc; it ain't even a v-brake. The typical Joe Schmoe might not understand that, and Sturmey-Archer probably doesn't want to get into the risk & complication of trying to explain that many dim-bulbs like you and I run drums offroad, and we have adjusted our expectations accordingly. The fact is, if you're the type of person who takes a heavyweight mild steel cruiser frame, hangs a lot of '50's-tech components on it, puts some knobbies on it, and considers running
coaster-only, you're absolutely as prepared as you'll ever be to deal with heat-induced brake fade and a general lack of impressive braking power that comes from running a drum offroad. You're also not the type of person Sturmey-Archer and other manufacturers need to educate about "intended use", b/c you're piloting either a 70 year-old newsboy bike or a late-model industrial bike on singletrack, so the notion of "intended use" seems like a low priority. Schwinn of Chicago and other firms like Worksman never intended their bikes to be ridden hard on the trail, but some of us knuckleheads do it anyway.
Like I said before, the power of the X-FD is kinda underwhelming if you're used to discs, and something I forgot to mention before: the first hundred miles, you'll want to unlace the hub and send it back b/c the "power" is comically weak until the pads wear in. In the best conditions, you can tune the drum to work silently, reliably, and with enough braking authority to handily get the job done... You'll need to get the cable tension just right, and you'll need to be running short-pull levers, and you'll want a fairly clean (no sharp turns, few bends) run of housing. (I'm going to upgrade to compressionless housing soon; I was amazed at what that simple mod did for my road calipers, so I'm
hoping it'll do something similar for my drums.) If you were white-knuckling downhill in a sustained fashion, the drum will get hot, the lever will feel dead, and braking performance will go down the tubes. Best to lean the bike against a tree, take a pee, and sit on a stump & enjoy nature for a few minutes whilst things cool down. (Incidentally, at this point, your coaster might be even more deserving of a break, and will probably need a repack.) If the drums are honking/ squealing/ squawking when engaged, you've either got something in the drum that you'll need to clean out (h2o, chain oil, mud, squirrels?) or you've got cable tension issues--- time to retune. If it's squealing when you're not squeezing the lever, you got the cable too tight and the pads are dragging... turn the barrel in an 1/8th turn or so.
