Originally Posted by
non-fixie
Caption Contest Time!
"Now where did that uber-rare French reverse-thread 7.25mm nut disappear to?"
Originally Posted by
Roger M
Hey Jim, something I haven't put much thought into, and you've peaked my interest. How tight is the timing chain supposed to be? I haven't adjusted the tension on mine since I've had it (probably due to not having any problems with it).
AFAIK it needn't be real tight but at least tight enough that it can't jump a tooth. That would have to be loose indeed and probably doesn't happen too often. But I think they look sloppy if they sag too much so I've checked it every few thousand miles or so. That helps keep the eccentric free too. And a tighter chain gives better tactile feel for what the other rider is doing.
When you tighten it spin the pedals backwards and see how it does through the pedal cycle. Depending on the chainrings' and spiders' roundness the tightness may not be constant.
One clever way to take up timing chain slack if your eccentric is stuck or has no more take-up capacity is to insert a ghost ring between the upper and lower segments somewhere between the two cranks. If it is slightly larger than the chainrings it pulls the slack out of the chain by making it take a non-direct path between them. Nothing holds it in place except the chain itself and the fact that the upper and lower segments are moving in opposite directions at exactly the same speed.