Bicycle Mechanics - Chain falling off middle ring

hi I replaced my sram chain about a month ago(took a maintenance course and the mechanic helped me size the chain properly) and I have broken it once and used a master link to get back up and running

over the weekend I noticed getting from my granny to the middle was pretty sluggish and last night when I was hitting large bumps or a series of small ones my chain was dropping to the small ring but was like putting a car in neutral because I had zero power... just spun and nothing.

is this a derailleur adjustment generally?

or could I have stretched my chain enough to have this happen?

If everything was okay before you replaced the chain, then that almost certainly caused the new problem. A badly worn chainring MIGHT be the culprit (they do some odd things when mated to a fresh chain), but my guess is you may have purchased the wrong chain for the bike. Sounds to me like the chain is too narrow.

BL

If everything was okay before you replaced the chain, then that almost certainly caused the new problem. A badly worn chainring MIGHT be the culprit (they do some odd things when mated to a fresh chain), but my guess is you may have purchased the wrong chain for the bike. Sounds to me like the chain is too narrow.

BL

it worked fine after I replaced the chain for 3 or 4 weeks just recently started

I've always been told (in the road racing community) that if you wore out a chain, you probably wore out the cassette too. How you can tell is if you put a new chain on it will skip or slip on the gears you use most often, which are the most worn. That's what it sounds like, but checking for bound up links is easy enough too - sit the bike upside-down on the bars and seat and spin the cranks backwards. If a link is sticking it will hold an angle as it comes off the dérailleur wheel toward the chainring.

General rule of thumb is to replace both chain and cassette.

Was the neutral feeling very quick?

This is either

a) Fluke accident
b) Improper Front derailleur adjustment

Inspect the front chainrings for significant wear, this should be excruciatingly obvious.

General rule of thumb is to replace both chain and cassette.

Was the neutral feeling very quick?

yes it is very quick but it is the front middle ring not my rear cassette.

feels like a dropped chain because the chain ends up between the middle and granny rings so it doesn't engage

I'm gonna mess with my front derailleur see if I can get anywhere with the issue

I'll start with the barrel adjusters then adjust the cable tension(at the derailleur) if I find there is considerable changes needed with the barrel adjusters

I'm gonna mess with my front derailleur see if I can get anywhere with the issue

I'll start with the barrel adjusters then adjust the cable tension(at the derailleur) if I find there is considerable changes needed with the barrel adjusters

This gets you nowhere. Do the procedure from top to bottom.

http://www.parktool.com/repair/readhowto.asp?id=75

What operator said. Barrel adjusters are just a stop-gap measure.

What operator said. Barrel adjusters are just a stop-gap measure.

Huh? If his shifting was fine before, what else besides cable tension could have changed? Sounds to me like he needs to add some cable tension to bring the front derailler closer to the chain. He didn't say but I'm guessing the chain is falling off the middle ring when he is using the large cogs on the cassette. I've fixed this problem on a few bikes simply by getting the front derailler as close as possible to the chain when in the middle/big combo.

Huh? If his shifting was fine before, what else besides cable tension could have changed? Sounds to me like he needs to add some cable tension to bring the front derailler closer to the chain. He didn't say but I'm guessing the chain is falling off the middle ring when he is using the large cogs on the cassette. I've fixed this problem on a few bikes simply by getting the front derailler as close as possible to the chain when in the middle/big combo.

Thus demonstrating complete ignorance.

I've fixed this problem on a few bikes simply by getting the front derailler as close as possible to the chain when in the middle/big combo.

Even so, you'd be better off doing that by redoing the whole cable system and the limits as opposed to just using the barrel adjusters. IME, using the adjusters requires readjustments quite a bit, perhaps every 100 miles. I'd rather take it all apart and not have to deal with it every so often.

On top of that, the FD is one of the more finicky components and it would be worth everyone's while to take the time to go over the whole system. Or just do away with it altogether.

Even so, you'd be better off doing that by redoing the whole cable system and the limits as opposed to just using the barrel adjusters. IME, using the adjusters requires readjustments quite a bit, perhaps every 100 miles. I'd rather take it all apart and not have to deal with it every so often.

He said it worked fine before so I'm assuming that the limits screws are ok. The limit screws do not position the front derailler over the middle chainring; cable tension does. Once everything has broken in and been readjusted (by adding tension through the barrel adjusters), you shouldn't need to touch anything for a long time.

Thus demonstrating complete ignorance.

Explain.

in the article i'm assuming inner most means largest rear cogs and outer most means smalllest

opposite for the front

Inner means closest to the center of the bike so yes.

yes it is very quick but it is the front middle ring not my rear cassette.

feels like a dropped chain because the chain ends up between the middle and granny rings so it doesn't engage

Tell us exactly what drivetrain you have and what the replacement chain is.

This problem seems unusual. If the derailleur is knocking the chain off or the middle chainring it may be caused by too much tension in the front shift cable or not enough. But it's hard to understand why the chain is skating on the inner ring unless there is a compatibility problem. I have seen this happen with a narrow 10-speed chain on a 9-speed triple.

Al

Come to think of it, I have seen this happen when I installed a ring on backwards.