Front Derailleur issue

[chengher87]

My dad's bike has a shifting issue on the front derailleur. When shifting on the workstand, the shifting works perfectly, moving from the 42T to 52T quietly. However, when he's on the road and shifting from the 42T to 52T, it doesn't quite shift all the way and the chain is caught in a position where it starts to grind on the two chainrings. He shifts back down and then shifts up again, where it shifts, but not without some noise and difficulty. Why is this? It shifts fine on the workstand, but not on the road. I'd take it to an LBS, but as my dad says "That's a waste of money! We can do that ourselves". Although he did say that with fixing the stove....and we ended up having to buy a new stove.

[jtakeda]

Worn chainrings is my first guess

[chengher87]

Took apart chain-ring and switched sides for the 42T and now it works both on the stand AND on the road. Didn't know there was specificity there. Now I feel like Homer Simpson when he tried to put together a grill. LE GRILL!?? What the hell does that MEAN!?

Lesson learned and I'll never forget now.

[oldpotatoe]

My dad's bike has a shifting issue on the front derailleur. When shifting on the workstand, the shifting works perfectly, moving from the 42T to 52T quietly. However, when he's on the road and shifting from the 42T to 52T, it doesn't quite shift all the way and the chain is caught in a position where it starts to grind on the two chainrings. He shifts back down and then shifts up again, where it shifts, but not without some noise and difficulty. Why is this? It shifts fine on the workstand, but not on the road. I'd take it to an LBS, but as my dad says "That's a waste of money! We can do that ourselves". Although he did say that with fixing the stove....and we ended up having to buy a new stove.

Trying to shift to the big ring, 'under load'(riding), can be noisy and not quite as smooth as in the stand, where the pedal pressure is so low. Make sure the clearances are correct..and the outer limit screw is out far enough..are the chainrings a 'modern' type with pickup pins and such? Or an older w/o such things. If w/o, get a modern one.