Whats wrong with my bike?
I know, these questions are annoying and trying to diagnose a problem through the internet is not the best way to go. But I have 2ish weeks of riding before this bike goes into long term storage and stops being my primary ride and I don't want to spend any more money on it. Recently the chain has been jumping gears all over my rear cassette during almost every pedal stroke and I am constantly having to shift get back to the gear I need to be in. The only thing I can think of that might be the cause is that I laid the bike down on the drive side on the ride before it started happening, but it was at a slow speed in soft soil and so far I cannot see any damage that would be a smoking gun. Whats going on here?
Additionally I have an unrelated question that I don't want to start a new thread about, but how do you guys keep the chain from coming off when riding? It seems like half the time I go over a rock garden, log crossing, or section of roots my chain is dangling off the bike afterwards.
It sounds like you need to lube /replace the cables. That or the chain/ cassette need replacing.When was the last time you lubed the cables? How old are the chain/cassette?What gear are you in when the chain comes off,where does it fall out ,off the small chain ring in the front or off the big cog in the back. You may need to ride those things in a different gear.
Took the bike in to be serviced at the end of May, not sure if he lubed the cables or not, Ill do that now. The chain and cassette are the originals that came on the bike, which was bought in 2004 or 2005. When my chain falls off Im almost always in the smallest chain ring up front, but it has happened on the medium chain ring as well. Not sure what gear Im in on the cassette, I believe it happens on multiple gears. I try to stay on the smallest chain ring up front because it is such a chore to get my bike to shift up to the bigger chain rings, I can't even tell you the last time I rode on the largest chain ring.
If you ride very much it is close to time to replace the chain and cassette and the chain rings. Take a look at the teeth on the chain rings compare the shape of the little to the big ,if the little profile is more rounded it is worn . You can measure the chain to see if it worn look on the Park tools web site for more info. It shouldn't be that hard to shift ,that leeds to think that the cables need lubing/replacing. Again if you ride much those cables and houing need to be replaced.
Even a subtle hit can slightly bend your rear derailleur or the derailleur hanger. that can screw up the whole drivetrain. on my last ride, it happened to me. the cage on my rear derailleur (the plates that hold the pulleys) got bent (how, I dunno) which threw off my shifting and my chain got thrown off the top cog and was jammed in the machined-out space between the wheel and cassette that took me half an hour to extract after I managed to access my power link and get the chain off. I bent the derailleur back and my shifting was fine.
Originally Posted by SDKmann
as for chain drop problems, there are several factors involved.
the first is to ensure that everything is properly adjusted. poor adjustment will result in a lot of problems that can drop chains so start here.
another factor is technique. If you're hitting rock gardens and such in a gear ratio that has the rear derailleur taking up a lot of slack in the chain, then you run the risk of dropping the chain more because it can just bounce off. Use your middle ring is possible. This can be exacerbated by a low end drivetrain where the springs are wimpy. Using a rear derailleur with a stiff spring can help keep things in place.
if you've still got problems, there are products that can help. there are plenty of chain guides on the market for aggressive riders. I don't know of any that work with a triple chainring drivetrain, though. There are models that will work with a double IIRC. there are also little cheap anti-drop doodads that you can attach to your seat tube that can help...but IMO those things are a crutch for people who don't properly maintain their drivetrain.
I just keep my drivetrain properly adjusted and maintained and I have very few occasions where I drop the chain. when I do, it's usually because I've crashed.
Ill have to read up on some maintenance guides and start there as it sounds like that is the cause of some if not all my problems, as is wear and tear. The bike has not received the proper love and attention its whole life, partially out of my own ignorance since this was my first bike that I bought in high school and I just didn't know any better. Ill try some of the maintenance tips since even if Im at the point where I need to start replacing things this bike is about to become a backup anyways. Im moving to China in a few weeks and will be buying a new trail rig there, hence why I am not putting any more money into this bike. Thanks for all the tips guys, this site is always extremely helpful.
As for the proper gearing for different obsticles, such as rock gardens, is there any resource you know of that could teach me some things? I just ride and have never had any instruction on how to tackle trails and Im almost always out there on my own. Sounds like my ignorance of a lot of things is really holding me back.
Could be something simple like the cable stretched? YouTube has some decent tutorials on adjusting the derailer. I used Intown Bicycle.
Well, mystery partially solved. Just got back from a short ride and while on a paved trail watched the drivetrain as I pedaled. A lot of the jumpiness looked like it was coming from the chainrings so I pulled the chain back and looked at the teeth. On the smallest ring (the one Im usually on) there are at least 2 teeth that are about half the size of the ones next to them, middle ring has some obvious wear as well. Surprisingly there are two teeth next to each other on the largest ring that are also half the size of the rest. I think these may have been sheared off, possibly during a wreck. Guess Ill have some work to do on this bike when I pull it out of storage. On the plus side though I don't feel nearly as bad now about cannibalizing it for parts.
the teeth on your middle ring should all be the same, but not on the other two. the middle and big chainrings are involved with shifting to larger gears, so those rings are ramped and/or pinned to help the chain move up. there's really not much of a reason to use the small ring all the time. that's what the middle ring is for. the small ring is for climbing. I only ever use my big ring when riding pavement to the trails. when on the trails, I don't ever touch the big ring.
if you are in the small ring when you hit technical sections, that explains why you're dumping the chain. there's a lot of slack in the chain that your rear derailleur has to take up, and when your bike bounces in the tech, the spring in the derailleur bounces and your chain pops off.
use the middle ring more, and there's more tension (and less slack) on the system, so the derailleur will bounce less and you'll drop the chain less. that won't cost you a dime.
but with your shifting problems and history behind the bike, I suspect that in addition to worn components, you could possibly still have a bent hanger or derailleur and poor adjustment.