What is the difference between right and left gear shifters on a bicycle? What are their functions?

Question

I am a novice bicycler and having a great deal of trouble getting the settings right on my 18 speed mountain bike. There are no setting markers, only two unmarked levers- one on each handle bar. They tend to not want to stay in one place (migrating slightly) from time to time, and I'm always getting a ticking/grinding noise from peddaling. I really injured my knee on a ride this past weekend and have another one coming up in two weeks...so I'd like to figure out a good setting that will alleviate pain and prevent it from happening again. What does the left shifter adjust exactly...and what does the right one control? Which way do I turn them to make peddaling easier or harder? How do they work together for optimal performance? This may seem like a pathetic question, but as I said I am a novice- any advice will be greatly appreciated:)

Answer 1

The left shifter controls the front gears (chainrings). The smallest chainring is the lowest gear and easiest to pedal. The right shifter controls the rear gears. The smallest rear gear is the highest gear and hardest to pedal. So the smallest rear gear and the largest front gear is your biggest gear. The largest rear and smallest front is your lowest gear. Some combination of the front and rear gears will be the right gear for you depending on wind speed and direction, uphill or downhill, your cycling ability, etc. Try to keep your cadence at about 80-90 rpm for the most efficiency. That will also minimize knee strain. Knee pain could also be caused by a poor seat adjustment.  When the pedal is at the down stroke, your knee should be just slightly bent.

It might seem a bit confusing at first, but it will soon become second nature.

Answer 2

if your bike is set up properly, the left shifter controls your front derailleur, the right your rear derailleur. your front derailleur switches between 2-3 chainrings, depending on your setup. you should be using your inner/smallest chainring for climbing, and outer/larger chainring for flats & downhills. your rear derailleur changes the gears on your cassette (anywhere from 5-10 cogs depending on the age and/or quality of your drivetrain). these make for more subtle changes in your gear ratio. when on your rides, ride with folks who can coach you as to your cadence and gearing. most experienced riders are happy to provide some advice to newbies. you'll now have learned something about your own riding style that you can improve on on your own too!

as to the ticking, you may be in gears that don't naturally work (big ring - big cog/ small ring - small cog). either way, you're probably rubbing your chain on a derailleur or teeth on another ring or cog, or on big to big, you are stretching your chain as well. also, you may be between gears. you may have shifted while the bike was stationary, or tried shifting your front and rear simultaneously. try cranking your pedals and shifting through your gears. it may be your derailleurs need adjusting.

as for the pain, yes a lot of it may be from not shifting properly, but it may also be that the bike is a bad fit for you.

1. where did you buy the bike? if yard-sale, ebay, wal-mart, target, etc. understandably, it wasn't fitted, or any of the components explained to you. so take it to a bike shop, where a professional can help you. they can help you get the seat positioned properly, and adjust your gears, and explain to you how to shift. expect to pay them for this service, they didn't sell you the bike, and owe you no favors! if you did buy from a bike shop, and they didn't do this for you, they should have, and should make good for no cost, if this was a recent purchase. I would, however, consider doing business with another local dealer going forward, as it doesn't say much for how they view their clientel.

short story-long, get to the bike shop before your next ride!