how do you adjust the gears on a mountain bike?

Question

I cannot access the largest chainwheel (Front) on my bike, can anyone give me a straight, easy answer?

Answer 1

The front derailleur has a coupel adjustments you can work with. If you haven't had the bike adjusted recently, and you haven't crashed and hit the front derailleur, then all you SHOULD need to do is adjust your cable tension. I wish I knew your specific bike or shifter brand and model as it would make this a little easier, but these instructions will be correct regardless.
Your left shifter controls the front derailleur and there is something called a "barrel adjuster" which is where the black cable housing goes into the shifter. You will notice that part has ridges or knobs on it which make it easy to grip with your fingers. What you are trying to do is INCREASE cable tension in order to help the chain rise up to the next chainring. The way to do that is to UNSCREW the barrel adjuster 1 click at a time. As you unscrew it (if it is a Shimano shifter) you should feel it click about every 1/4 turn. To start with, unscrew it about 3 clicks, and go ride it and try shifting. If it still doesn't shift up, you can adjust it while you ride... Just unscrew it another couple clicks while you ride, and it should want to jump up to the high gear in no time. Once you have done that, back the barrel adjuster off about 1 click. Once you have done all this, the next thing to do is see if it wants to "overshift" or throw the chain over the top of the large chainring. While riding after you have gotten the chain to shift properly, shift into the large chainring, and while pedaling, try shifting as if there was an even larger chainring. If it starts clicking or it actually throws the chain over the top, just stop, put the chain back on the big chainring, and take a close look at the front derailleur. You will see 2 small screws marked "L" for Low (small gear) and "H" for High (large gear). You will want to screw the H screw in (tighten) about 1/4 of a turn and go ride and attempt the same thing again, and repeat that process until you are successful. If you tighten the H screw too much, you might prevent the chain from coming up to the large ring, if that is the case, just back the H screw off 1/4 turn at a time until it does shift back up to the big chainring.

Hope this helps, and if you have any other questions, feel free to message me!

Answer 2

The cable tension dial/plastic twiddly thing (theres one on the shifter and on the derailleur [rear only] - where the cable leaves the unit) adjusts the derailleurs movement between shifts. Then there are H (high) and L (low) screws on the derailleur that limit the derailleurs movement from its extremities - to stop it pulling the chain completely off of the rings.

Gear cables stretch over time so need tightening, rotate the cable tensioner anti-clockwise to add more tension to the cable, if your gears worked fine originally, then tweaking the tension will solve the problem. If the gears shift fine after altering the tension but you still cannot use the biggest/smallest ring , then screw either the high/low screws out a bit (you'll have to look to see which one needs adjusting).

This is a piece of cake to do, it only takes 5 mins, so many people can't do it simply because the try to adjust the High/low screws in order to tune the gears.

Don't bother taking it to the bike shop - this task is worth learning, as you will need to do it every 4 months or so. After a year or two, or if the cable is coming a part, the cable will need replacing. If the gears skip alot then the chain and front and back chain rings will need replacing - which costs a bit!

Answer 3

Its the rear chain wheel that has different ratios, it is much easier to pay someone at the bike shop to do it, believe me.

Answer 4

I never figured it out, even with a manual.
For about £8.00 I think that you can get it done at any local bike shop though.

Answer 5

where theres a will theres a way