Ok, I bought a bike from a swap meet here in San Diego, a Specialized Hardrock Sport that needed some work, got it cheap. I found when I was trying to adjust the front derailleur that front derailleur was bent to hell. So I get a replacement at a LBS, Deore LX model. I can't seem to get the derailleur to jump to the biggest gear on the crank, can anyone give me some insight on what I may be doing wrong? I can get it to the middle gear as well. Is there a very specific height it needs to be at?

If you installed it yourself there is a chance that you don't have it adjusted properly. There are screws that control how far in or out it can travel. The other thing that comes to mind is are you sure it is a derailleur for a triple chainwheel?

Google front derailleur adjustment, add parktool or sheldon for two of the best sites. It's important to have a freely running cable as well as the proper height and rotation of the derailleur, not just limit screw adjustment.

I installed the front derailleur with screws all the way out. It seems when I stall to high it does want to shift to bigger gears. However when I lower the derailleur it works better, which makes it seem like there is a small sweet spot. And yes this is a 3 ring design, an M570 I think.

No, there is a proper adjustment, and it's not all the way out. You adjust the limits once the derailleur is correctly mounted. I think you need some editing here "stall to high"?? It does or does not want to shift??

Yes there is a sweet spot for height and it is quite close to the large chainwheel. Please confirm that you have followed the height and rotation guidelines at https://www.parktool.com/blog/repair-...ur-adjustments and then adjusted the limit screws, and then readjusted the cable tension if necessary.

Sorry bout the grammatical errors. Posting from m y galaxy s3. I will verify when I get home.