How to pick a front derailleur
 

Bought a GT outpost on CL and am having a problem with the front derailleur in that it will not drive all the way to the small sprocket. There was no brand on it and it was in bad condition. I bought a similar replacement (Shimano NEXAVE) at the co-op but having the same problem. Not attaching the gear cable, just trying to adjust by using the limit screw. The derailleur is bottom pull and 31.8 diameter.

The bike has an Acera rear derailleur, can I just buy an Acera front derailleur and expect it to fit?
Thank you.

The L limit screw is all the way out and it still won't shift to the smallest chainring? There's a chain on the bicycle, you're turning the cranks, and it won't go from the middle to the smallest chainring?
First thing to check is the position of the derailleur - is it on straight (parallel with chain), is it on low enough (as close to chainrings as possible).

Yes that is correct, limit screw all the way out, will not jump to the small chain ring when pedaling, derailleur aligned straight, and height is about right. I've adjusted front derailleurs before but have never run across this problem, usually with no cable attached I can use the limit screw to adjust them properly. I'm assuming I have the wrong type of derailleur.

Sounds like the BB spindle is too long.
Have you changed the cranks or BB?

Nope, it’s the *small* chainring that the derailleur can’t reach.

Here’s my thought. Is the “tail” of the front derailleur hitting the chain stay? Some derailleurs are rather long and if they are mounted to low on the seat tube, they will hit the stay.

Not enough coffee yet-
Change that to TOO SHORT!

I frequently make similar errors before coffee!

Not Shimano specific..

triples add a deeper pusher plate to deal with greater differences in chainring diameters, the mid to larger difference has to be 10t..

I have the same FD on 2 bikes , older over the BB shift cable routing requires a 52-42.. 26 , or the cable interferes with the bottom of the FD,

Under the BB riute I have a 50-40 ..24...






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