wunderkind

Hi,
Lately I am having trouble shifting to the largest ring (triple) when I am riding. However when I am off my bike and re-tighten the cable, it shifts fine. Then hop back on... nope! It's so annoying. I actually rode to work on my 38t the whole time through last week! Going downhill and flats were a sad affair.

Infidel79

Shifting under load is often more difficult than on the repair stand. Does the cable require frequent re-tightening? Is the cable slipping in the pinch bolt at the derailleur? If it's a clamp-on derailleur, has it moved on the seat tube? Is the cage bent?

Kimmo

You might try backing off the high limit screw a hair - but not too much or you could throw the chain.

fietsbob

So it wont upshift, going downhill, when there is, also,no tension on the chain,? spinning lightly
so the chain can climb upto the big diameter. still wont go?

Al1943

If you work the smaller shift lever several times, with all of the cable out of the shifter there should be no slack in the cable. If there is slack that could be the problem.