the ally eccentrics are FULLY adjustable (ie you can fit them in any position thoughout the 360 degree's) whereas the plastic only have a limited amount of movement.
I found I couldn't get the rear belt tensioned correctly with the plastic eccentrics, but was spot on with the ally ones.
Also I've broken a couple of rear plastic pivot blocks recently.
So my advice would be to fit all the ally bits :-)
|