newbie question about tightening gears?

[goblinmarket]

i ride my bike a lot, to commute, exercise, etc. but i consider myself a newbie when it comes to maintenance. i usually roll it over to my local bike shop and pay their fees, but at the moment i'm close to flat broke (college). here goes...

sometimes when i go up a moderate hill (mostly street bridges here in chicago) or accelerate after a stoplight/sign, my gears shift on their own. i suspect they're loose. i was wondering if someone could point me towards a website that could help me -- or if someone could tell me how to remedy this. is this a really complicated thing to fix or can i fix it myself (in the interest of saving $). or if buying tools, etc., would be just as expensive as taking it in. i'd have to buy a new service contract for like $30+labor, etc. (it's kind of pathetic, but i could make this $30 go a long way otherwise). anybody?

 

[Dietmar]

What kind of a gear shifter/derailleur are we talking about? Typically, the main reason for gears "shifting by themselves" is a simple misadjustment, which is trivial to fix. Next most popular reason for this behavior is worn cogs and/or chain. How many miles do you have on this, and how well maintained (lubricated/cleaned) did you keep your drivetrain? If that is the issue, then you should probbaly replace both the chain and your cassette (the set of cogs on your rear hub). Both of these should be fairly easy to do as well, even for a newbie, although you may need to buy a (fairly inexpensive) tool to change the cassette and chain.

 

[garage sale GT]

sheldonbrown.com.

Distinctly remember something on there about autoshifting.

Also, why not try the library? My bikes would not work at all if not for Harold Washington.

 

[goblinmarket]

the bike is maybe a 2001...which i ride frequently -- if it's 45+ degrees out.

mileage? wow, very many. usually about 1 hr+/4 or more days a week (on the lakefront bike path, streets, or trainer) --sometimes 3hrs. on weekends. quite a bit of mileage (on and off-road), though i can't give you an exact number. i just know that i ride a lot, and am pretty reckless with it (jump curbs, carry groceries bungy corded to my rack, etc.). it's never really had too many problems, but it's a cheap schwinn MTB with shimano gears. everything is the same since i purchased the bike (but i'm not sure, since i've taken it in a bunch for maintenance). again, i ride a lot, but as far as maintenance -- clueless -- the LBS is a 20 min. roll away. i keep it well lubricated since the guy at the shop once told me all i needed was some WD 40 when i took it in for a tune-up a few months ago.

What kind of a gear shifter/derailleur are we talking about? Typically, the main reason for gears "shifting by themselves" is a simple misadjustment, which is trivial to fix. Next most popular reason for this behavior is worn cogs and/or chain. How many miles do you have on this, and how well maintained (lubricated/cleaned) did you keep your drivetrain? If that is the issue, then you should probbaly replace both the chain and your cassette (the set of cogs on your rear hub). Both of these should be fairly easy to do as well, even for a newbie, although you may need to buy a (fairly inexpensive) tool to change the cassette and chain.