I stumbled upon a nifty little thing today. Everyone loves a good singlespeed conversion, but when you’re converting a frame with vertical dropouts, you run into the age old problem or chain tension. There are several options available to you, the main contenders being the use of a chain tensioner, an eccentric hub, or an eccentric bottom bracket. All three have their downsides. A tensioner works a treat but takes away that clean, derailleur free aesthetic. Eccentric hubs are nice, but force your hand a little when it comes to wheel choice and don’t allow for a quick and easy conversion. Eccentric bottom brackets are even trickier, as you need a frame that is set up to accept an oversized BB, and they don’t work so well (read: at all) with new crank designs. Or at least, they never used to.
We were doing a little research in the shop today and found this nifty unit from Forward Components. It’s an eccentric bottom bracket designed for use with the new style external bottom bracket cups, and it fits into any standard 68mm bottom bracket shell. It’ll work a treat for singlespeed, internal gear hubs, and fixed gears. You get all the advantages of an eccentric bottom bracket, without having to buy a special frame. I’m not really in the market for anything like this, but there’s something about the simplicity and straight-forward look of these little thing that’s really struck a chord with me. It fits into the classic singlespeed ethos of keeping it simple and elegant.
They’re not super cheap (US$150), but in the grand scheme of things it’s not a huge outlay and it’ll solve a lot of problems in a very elegant manner. Hopefully someone will find it useful.
If anyone ends up buying on I’d love to hear how they go. Do they cut the mustard? Are they as good as they look? How the hell do you tighten it into the frame?