chain dropping

[OakLeaf]

Is your derailleur clean and lubed? If it's cruddy or dry after the winter, it could be slow to take up the slack when you upshift.

I suppose RD springs wear out over time, too ... I've never known that to happen, but springs generally lose their springiness, so if yours has a lot of miles on it, I'd think that would be a possibility, too.

[redrhodie]

I haven't cleaned the drive train well (okay, fessing up, I've hardly touched it ). It's cruddy. I'll also have my lbs measure the chain.

[Bike Writer]

The same thing was happening to me a lot last year in the later part of the year. Each time I dropped the chair it was on a downhill while shifting, I had it checked out at my LBS and they could not find anything wrong with it, not the derauiler, the chain itself or anything. Most of the time I was able to get it back on but once it got so fouled up that I had to walk the bike back to my car when I was out about 2 miles into the trail. I was not a happy camper.

At the end of the season last year I had a complete tune up and had one of the wheels trued up. So far I've dropped my chain once this year. I don't know what to say. I think it might be me. I've been more consience of shifting on downhills and have not dropped it again yet. Knock on wood, now I'll probably drop it tomorrow because I'm planning a longish ride

[westtexas]

I had a similar problem with my bike. The LBS didn't measure my chain but they replaced it and the problem was solved. Seems like a pretty simple (and cheap) thing to do to start eliminating possibilities for the root of the problem. I didn't even know you were supposed to be cleaning the chain. Now I use a degreaser every other week or so (it doesn't rain much now since the drought but there's plenty of dust kicked up!) and I've had a lot more luck getting the chain to last longer and I don't have the dropping problem anymore when I apply more power.

[laura*]

Each time I dropped the chair it was on a downhill while shifting, I had it checked out at my LBS and they could not find anything wrong with it, not the derauiler, the chain itself or anything.

There might not be anything "wrong" with the parts. This can be a characteristic of 1xN drivetrains. When shifting to a smaller cassette cog, the shift can happen suddenly and fast. This may cause a sideways wave in the chain. The front part of chain was still angled for the old cog while the back was bending over to the new cog. I think there's also an up and down wave from shifting into the smaller gear. These waves can be enough to throw the chain off the chainring when there's no derailleur to block them.

My commute bike has a single chainring up front. It came with a plastic guard on the outside of the chainring. When I changed to a smaller chainring, I installed metal guards on both sides. The guards are essentially toothless chainrings.

[redrhodie]

There might not be anything "wrong" with the parts. This can be a characteristic of 1xN drivetrains.

Yes, this is true. I know it's part of the problem, for sure. I am thinking about the guards, but I'm still looking for an alternative before I go that route. It may be the best thing, though.

[Bike Writer]

There might not be anything "wrong" with the parts. This can be a characteristic of 1xN drivetrains. When shifting to a smaller cassette cog, the shift can happen suddenly and fast. This may cause a sideways wave in the chain. The front part of chain was still angled for the old cog while the back was bending over to the new cog. I think there's also an up and down wave from shifting into the smaller gear. These waves can be enough to throw the chain off the chainring when there's no derailleur to block them.

My commute bike has a single chainring up front. It came with a plastic guard on the outside of the chainring. When I changed to a smaller chainring, I installed metal guards on both sides. The guards are essentially toothless chainrings.

1xN drivetrains? Does that mean only one chainring up front? I think that's what you mean, I have a chain guard and that does not prevent the chain from hopping off and also gets in the way when you are trying to fix a dropped chain. sigh.

[lph]

There might not be anything "wrong" with the parts. This can be a characteristic of 1xN drivetrains. When shifting to a smaller cassette cog, the shift can happen suddenly and fast. This may cause a sideways wave in the chain.

That's interesting, I'd think that with one chainring in front you'd be spared a chain ever falling off again. I never thought that the front derailleur would work as a chain guard. But 10 speed in back is a pretty wide spread for the chain to handle too. Park Tool (I think?) has a very neat and cheap little gadget called a chain checker btw, which tells you in a second whether your chain is worn. I love mine, and have recommended it as basic maintenance gear to many people.
Also the rear derailleur could be a little slow in taking up the slack if you've ridden in winter and it's a bit draggy, so that you have an instant where the chain has a shorter circle to travel but hasn't been pulled tight yet. Just an idea.

[laura*]

That's interesting, I'd think that with one chainring in front you'd be spared a chain ever falling off again.

That's what I thought too! Then I started researching what I needed to change the chainring on my commuter bike. The OEM guard of course wasn't suitable.

1x9 (and other cassette sizes) gearing is apparently popular on cyclocross bikes. Those riders "talk" a lot about needing guards.

[redrhodie]

That's what I thought too! Then I started researching what I needed to change the chainring on my commuter bike. The OEM guard of course wasn't suitable.

1x9 (and other cassette sizes) gearing is apparently popular on cyclocross bikes. Those riders "talk" a lot about needing guards.

Ah, I wish I had asked this before I decided on 10 speed. I also thought I'd never drop a chain on this bike, due to the single ring. Who knew?!

Thanks for all the input.