PH wrote:Nearly all the custom builders are using sliding rear dropouts to tension the chain, probably because these are easily available from Rohloff in small quantities. IMO an eccentric bottom bracket is a better option, you'll notice most of the manufacturers producing Rohloff bikes in numbers use this method, usually with their own design of dropout.
The 100 day trial period with a Thorn would put it high on my list of bikes to consider, I don't know of anyone else who offers this.
Yes, up to a point. The sliding rear dropouts are pretty good design (two M8 bolts to lock each side - i.e. twice the locking force per bike than most eccentric BBs, so hopefully less temptation to over tighten) and greatly preferable to running a chain tensioner (this negates a great deal of the advantage of hub gears over derailleur).
An eccentric BB would often be a more aesthetically pleasing solution, but its function depends to a great deal upon its design. Some eccentrics can prove very problematic, depending upon where and how they clamp up.
Thorn, I believe, always use eccentric BBs with Rohloff. This is OK, except on a tandem. Tandems depend upon an eccentric BB (usually at the front) to tension the timing (crossover) chain. Thorn use two eccentrics (front and back) on their Rohloff equipped tandems. I worry that this can encourage a circle of despair whereby you can only ever get one chain correctly tensioned until you weald the chain breaker. In a tandem application, one eccentric BB and sliding dropouts ( so that each chain is tensioned away from a fixed point – the rear BB) makes far more sense to me.
