Bicycle Mechanics - Gear problems

I recently have had problems switching to the 11th and 12th gears of my 18 speed mountain bike. A week ago it was fine, but now it won't switch over. Does anyone know what is going on here?

Another problem I have is switching from the the 7-12 speeds to either 1-6 or 13-18. Why is this?

It sounds like there some intelligent people in here when it comes to bikes, unfortunately I am not. :beer:

The cables that run form your shifters to the gears have stretched with age. Its time to go the you local bike shop (LBS) and get them the adjust your shifters. If they are a good shop they will charge you $10 for their beer kitty, If they arn't they may hit you up for a $80 "tuneup". You might want to call a couple of LBS and ask the price.

The bike is less than a year old and has only been used 10-15 times. I don't see how the could have aged when it has no age.

The cables will stretch while the bike is sitting in the garage. They are under tension in almost every gear.
Most cyclists either take their bikes back to the LBS to have the cables adjusted after 3 to 6 months or if they are knowledgeable about bike repairs will do their own adjustments.

Is it complicated to adjust it myself? What does it involve?

Buy the book 'zinn and the art of mtb maintenance' for $20 or go to www.parktool.com and check on their maintenance stuff.In no time you will be smarter than many here.Good luck.

Originally posted by pokey
Buy the book 'zinn and the art of mtb maintenance' for $20 or go to www.parktool.com and check on their maintenance stuff.In no time you will be smarter than many here.Good luck.

Hey, I would take that personal, if it wasn't true.

Youall realize that we're creating another biking addict!

Also, don't forget you should avoid using the extremes in your gearing. Don't use the combination of the big chainring (front) and the largest rear cog (i.e. the one closest to the wheel--i.e. gear 13), and don't use the small ring and the smallest cog (i.e. gear 6). The idea is that you don't want to have the chain running at too much of an angle--it'll wear out the parts faster. Moreover, there is always some overlap in the gear ratios (so, gear 11 is likely close to the same as gear 13).

Some would say you should also avoid gears 7, 12 (mid front with smallest and largest in back).

I would guess the cables are stretched. You might check on-line at www.sheldonbrown.com/articles.html. He may have something on how to adjust cables.

Once you get them tightened, and you get out on the road, what I said above will be more relevant.

Cheers,
Jamie

Shift down to 6th gear....(small small) Loosen the bolt on the dreailleur that holds the cable, and pull the cable tight if its loose. If its pretty tight already ude the barrell adjustor on the back of the derailleur to make it shift right, turn counterclockwise for more tension. If the chain shifts over the top gear, tighten the bottom screw on the derailleur until the chain dosent go over the top and your set to go.