Originally Posted by
79pmooney
Two points here. 1) the chain goes tightest climbing onto the cog, then settles down in between the teeth. So it can run fine in the large-large and still be problematic while shifting. When I've had things go wrong, it's always been during the shift, not JRA.
Being able to climb up to the largest cog can easily be tested in the stand while running through the gears. If it doesn't bind, it's fine.
Originally Posted by
79pmooney
2) A too loose small-small is rarely an issue beyond bad sounds (of the chain rubbing itself at the folded back lower idler pulley or dragging on the chainstay) and paint wear on the chainstay. I've set up triples many times with small-small chain rub and felt completely free to use that combo on long climbs that leveled out for a while and simply did not want to do a pair of double shifts. By contrast, big-big issues have me reaching into my pockets - for the cell phone now and wallet later.
Small-small should never go slack. There sound always be a little tension.